Imported Upstream version 60upstream/60

42 files changed, 6774 insertions, 0 deletions

diff --git a/src/pkg/crypto/openpgp/Makefile b/src/pkg/crypto/openpgp/Makefile
new file mode 100644
index 000000000..b46ac2bba
--- /dev/null
+++ b/src/pkg/crypto/openpgp/Makefile
@@ -0,0 +1,14 @@
+# Copyright 2011 The Go Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style
+# license that can be found in the LICENSE file.
+
+include ../../../Make.inc
+
+TARG=crypto/openpgp
+GOFILES=\
+	canonical_text.go\
+	keys.go\
+	read.go\
+	write.go\
+
+include ../../../Make.pkg
diff --git a/src/pkg/crypto/openpgp/armor/Makefile b/src/pkg/crypto/openpgp/armor/Makefile
new file mode 100644
index 000000000..138e314e9
--- /dev/null
+++ b/src/pkg/crypto/openpgp/armor/Makefile
@@ -0,0 +1,12 @@
+# Copyright 2010 The Go Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style
+# license that can be found in the LICENSE file.
+
+include ../../../../Make.inc
+
+TARG=crypto/openpgp/armor
+GOFILES=\
+	armor.go\
+	encode.go\
+
+include ../../../../Make.pkg
diff --git a/src/pkg/crypto/openpgp/armor/armor.go b/src/pkg/crypto/openpgp/armor/armor.go
new file mode 100644
index 000000000..9c4180d6d
--- /dev/null
+++ b/src/pkg/crypto/openpgp/armor/armor.go
@@ -0,0 +1,220 @@
+// Copyright 2010 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package armor implements OpenPGP ASCII Armor, see RFC 4880. OpenPGP Armor is
+// very similar to PEM except that it has an additional CRC checksum.
+package armor
+
+import (
+	"bufio"
+	"bytes"
+	"crypto/openpgp/error"
+	"encoding/base64"
+	"io"
+	"os"
+)
+
+// A Block represents an OpenPGP armored structure.
+//
+// The encoded form is:
+//    -----BEGIN Type-----
+//    Headers
+//
+//    base64-encoded Bytes
+//    '=' base64 encoded checksum
+//    -----END Type-----
+// where Headers is a possibly empty sequence of Key: Value lines.
+//
+// Since the armored data can be very large, this package presents a streaming
+// interface.
+type Block struct {
+	Type    string            // The type, taken from the preamble (i.e. "PGP SIGNATURE").
+	Header  map[string]string // Optional headers.
+	Body    io.Reader         // A Reader from which the contents can be read
+	lReader lineReader
+	oReader openpgpReader
+}
+
+var ArmorCorrupt os.Error = error.StructuralError("armor invalid")
+
+const crc24Init = 0xb704ce
+const crc24Poly = 0x1864cfb
+const crc24Mask = 0xffffff
+
+// crc24 calculates the OpenPGP checksum as specified in RFC 4880, section 6.1
+func crc24(crc uint32, d []byte) uint32 {
+	for _, b := range d {
+		crc ^= uint32(b) << 16
+		for i := 0; i < 8; i++ {
+			crc <<= 1
+			if crc&0x1000000 != 0 {
+				crc ^= crc24Poly
+			}
+		}
+	}
+	return crc
+}
+
+var armorStart = []byte("-----BEGIN ")
+var armorEnd = []byte("-----END ")
+var armorEndOfLine = []byte("-----")
+
+// lineReader wraps a line based reader. It watches for the end of an armor
+// block and records the expected CRC value.
+type lineReader struct {
+	in  *bufio.Reader
+	buf []byte
+	eof bool
+	crc uint32
+}
+
+func (l *lineReader) Read(p []byte) (n int, err os.Error) {
+	if l.eof {
+		return 0, os.EOF
+	}
+
+	if len(l.buf) > 0 {
+		n = copy(p, l.buf)
+		l.buf = l.buf[n:]
+		return
+	}
+
+	line, isPrefix, err := l.in.ReadLine()
+	if err != nil {
+		return
+	}
+	if isPrefix {
+		return 0, ArmorCorrupt
+	}
+
+	if len(line) == 5 && line[0] == '=' {
+		// This is the checksum line
+		var expectedBytes [3]byte
+		var m int
+		m, err = base64.StdEncoding.Decode(expectedBytes[0:], line[1:])
+		if m != 3 || err != nil {
+			return
+		}
+		l.crc = uint32(expectedBytes[0])<<16 |
+			uint32(expectedBytes[1])<<8 |
+			uint32(expectedBytes[2])
+
+		line, _, err = l.in.ReadLine()
+		if err != nil && err != os.EOF {
+			return
+		}
+		if !bytes.HasPrefix(line, armorEnd) {
+			return 0, ArmorCorrupt
+		}
+
+		l.eof = true
+		return 0, os.EOF
+	}
+
+	if len(line) > 64 {
+		return 0, ArmorCorrupt
+	}
+
+	n = copy(p, line)
+	bytesToSave := len(line) - n
+	if bytesToSave > 0 {
+		if cap(l.buf) < bytesToSave {
+			l.buf = make([]byte, 0, bytesToSave)
+		}
+		l.buf = l.buf[0:bytesToSave]
+		copy(l.buf, line[n:])
+	}
+
+	return
+}
+
+// openpgpReader passes Read calls to the underlying base64 decoder, but keeps
+// a running CRC of the resulting data and checks the CRC against the value
+// found by the lineReader at EOF.
+type openpgpReader struct {
+	lReader    *lineReader
+	b64Reader  io.Reader
+	currentCRC uint32
+}
+
+func (r *openpgpReader) Read(p []byte) (n int, err os.Error) {
+	n, err = r.b64Reader.Read(p)
+	r.currentCRC = crc24(r.currentCRC, p[:n])
+
+	if err == os.EOF {
+		if r.lReader.crc != uint32(r.currentCRC&crc24Mask) {
+			return 0, ArmorCorrupt
+		}
+	}
+
+	return
+}
+
+// Decode reads a PGP armored block from the given Reader. It will ignore
+// leading garbage. If it doesn't find a block, it will return nil, os.EOF. The
+// given Reader is not usable after calling this function: an arbitrary amount
+// of data may have been read past the end of the block.
+func Decode(in io.Reader) (p *Block, err os.Error) {
+	r, _ := bufio.NewReaderSize(in, 100)
+	var line []byte
+	ignoreNext := false
+
+TryNextBlock:
+	p = nil
+
+	// Skip leading garbage
+	for {
+		ignoreThis := ignoreNext
+		line, ignoreNext, err = r.ReadLine()
+		if err != nil {
+			return
+		}
+		if ignoreNext || ignoreThis {
+			continue
+		}
+		line = bytes.TrimSpace(line)
+		if len(line) > len(armorStart)+len(armorEndOfLine) && bytes.HasPrefix(line, armorStart) {
+			break
+		}
+	}
+
+	p = new(Block)
+	p.Type = string(line[len(armorStart) : len(line)-len(armorEndOfLine)])
+	p.Header = make(map[string]string)
+	nextIsContinuation := false
+	var lastKey string
+
+	// Read headers
+	for {
+		isContinuation := nextIsContinuation
+		line, nextIsContinuation, err = r.ReadLine()
+		if err != nil {
+			p = nil
+			return
+		}
+		if isContinuation {
+			p.Header[lastKey] += string(line)
+			continue
+		}
+		line = bytes.TrimSpace(line)
+		if len(line) == 0 {
+			break
+		}
+
+		i := bytes.Index(line, []byte(": "))
+		if i == -1 {
+			goto TryNextBlock
+		}
+		lastKey = string(line[:i])
+		p.Header[lastKey] = string(line[i+2:])
+	}
+
+	p.lReader.in = r
+	p.oReader.currentCRC = crc24Init
+	p.oReader.lReader = &p.lReader
+	p.oReader.b64Reader = base64.NewDecoder(base64.StdEncoding, &p.lReader)
+	p.Body = &p.oReader
+
+	return
+}
diff --git a/src/pkg/crypto/openpgp/armor/armor_test.go b/src/pkg/crypto/openpgp/armor/armor_test.go
new file mode 100644
index 000000000..9334e94e9
--- /dev/null
+++ b/src/pkg/crypto/openpgp/armor/armor_test.go
@@ -0,0 +1,95 @@
+// Copyright 2010 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package armor
+
+import (
+	"bytes"
+	"hash/adler32"
+	"io/ioutil"
+	"testing"
+)
+
+func TestDecodeEncode(t *testing.T) {
+	buf := bytes.NewBuffer([]byte(armorExample1))
+	result, err := Decode(buf)
+	if err != nil {
+		t.Error(err)
+	}
+	expectedType := "PGP SIGNATURE"
+	if result.Type != expectedType {
+		t.Errorf("result.Type: got:%s want:%s", result.Type, expectedType)
+	}
+	if len(result.Header) != 1 {
+		t.Errorf("len(result.Header): got:%d want:1", len(result.Header))
+	}
+	v, ok := result.Header["Version"]
+	if !ok || v != "GnuPG v1.4.10 (GNU/Linux)" {
+		t.Errorf("result.Header: got:%#v", result.Header)
+	}
+
+	contents, err := ioutil.ReadAll(result.Body)
+	if err != nil {
+		t.Error(err)
+	}
+
+	if adler32.Checksum(contents) != 0x27b144be {
+		t.Errorf("contents: got: %x", contents)
+	}
+
+	buf = bytes.NewBuffer(nil)
+	w, err := Encode(buf, result.Type, result.Header)
+	if err != nil {
+		t.Error(err)
+	}
+	_, err = w.Write(contents)
+	if err != nil {
+		t.Error(err)
+	}
+	w.Close()
+
+	if !bytes.Equal(buf.Bytes(), []byte(armorExample1)) {
+		t.Errorf("got: %s\nwant: %s", string(buf.Bytes()), armorExample1)
+	}
+}
+
+func TestLongHeader(t *testing.T) {
+	buf := bytes.NewBuffer([]byte(armorLongLine))
+	result, err := Decode(buf)
+	if err != nil {
+		t.Error(err)
+		return
+	}
+	value, ok := result.Header["Version"]
+	if !ok {
+		t.Errorf("missing Version header")
+	}
+	if value != longValueExpected {
+		t.Errorf("got: %s want: %s", value, longValueExpected)
+	}
+}
+
+const armorExample1 = `-----BEGIN PGP SIGNATURE-----
+Version: GnuPG v1.4.10 (GNU/Linux)
+
+iJwEAAECAAYFAk1Fv/0ACgkQo01+GMIMMbsYTwQAiAw+QAaNfY6WBdplZ/uMAccm
+4g+81QPmTSGHnetSb6WBiY13kVzK4HQiZH8JSkmmroMLuGeJwsRTEL4wbjRyUKEt
+p1xwUZDECs234F1xiG5enc5SGlRtP7foLBz9lOsjx+LEcA4sTl5/2eZR9zyFZqWW
+TxRjs+fJCIFuo71xb1g=
+=/teI
+-----END PGP SIGNATURE-----`
+
+const armorLongLine = `-----BEGIN PGP SIGNATURE-----
+Version: 0123456789abcdefghijklmnopqrstuvwxyz0123456789abcdefghijklmnopqrstuvwxyz0123456789abcdefghijklmnopqrstuvwxyz0123456789abcdefghijklmnopqrstuvwxyz0123456789abcdefghijklmnopqrstuvwxyz0123456789abcdefghijklmnopqrstuvwxyz0123456789abcdefghijklmnopqrstuvwxyz0123456789abcdefghijklmnopqrstuvwxyz0123456789abcdefghijklmnopqrstuvwxyz
+
+iQEcBAABAgAGBQJMtFESAAoJEKsQXJGvOPsVj40H/1WW6jaMXv4BW+1ueDSMDwM8
+kx1fLOXbVM5/Kn5LStZNt1jWWnpxdz7eq3uiqeCQjmqUoRde3YbB2EMnnwRbAhpp
+cacnAvy9ZQ78OTxUdNW1mhX5bS6q1MTEJnl+DcyigD70HG/yNNQD7sOPMdYQw0TA
+byQBwmLwmTsuZsrYqB68QyLHI+DUugn+kX6Hd2WDB62DKa2suoIUIHQQCd/ofwB3
+WfCYInXQKKOSxu2YOg2Eb4kLNhSMc1i9uKUWAH+sdgJh7NBgdoE4MaNtBFkHXRvv
+okWuf3+xA9ksp1npSY/mDvgHijmjvtpRDe6iUeqfCn8N9u9CBg8geANgaG8+QA4=
+=wfQG
+-----END PGP SIGNATURE-----`
+
+const longValueExpected = "0123456789abcdefghijklmnopqrstuvwxyz0123456789abcdefghijklmnopqrstuvwxyz0123456789abcdefghijklmnopqrstuvwxyz0123456789abcdefghijklmnopqrstuvwxyz0123456789abcdefghijklmnopqrstuvwxyz0123456789abcdefghijklmnopqrstuvwxyz0123456789abcdefghijklmnopqrstuvwxyz0123456789abcdefghijklmnopqrstuvwxyz0123456789abcdefghijklmnopqrstuvwxyz"
diff --git a/src/pkg/crypto/openpgp/armor/encode.go b/src/pkg/crypto/openpgp/armor/encode.go
new file mode 100644
index 000000000..99dee375e
--- /dev/null
+++ b/src/pkg/crypto/openpgp/armor/encode.go
@@ -0,0 +1,161 @@
+// Copyright 2010 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package armor
+
+import (
+	"encoding/base64"
+	"io"
+	"os"
+)
+
+var armorHeaderSep = []byte(": ")
+var blockEnd = []byte("\n=")
+var newline = []byte("\n")
+var armorEndOfLineOut = []byte("-----\n")
+
+// writeSlices writes its arguments to the given Writer.
+func writeSlices(out io.Writer, slices ...[]byte) (err os.Error) {
+	for _, s := range slices {
+		_, err = out.Write(s)
+		if err != nil {
+			return err
+		}
+	}
+	return
+}
+
+// lineBreaker breaks data across several lines, all of the same byte length
+// (except possibly the last). Lines are broken with a single '\n'.
+type lineBreaker struct {
+	lineLength  int
+	line        []byte
+	used        int
+	out         io.Writer
+	haveWritten bool
+}
+
+func newLineBreaker(out io.Writer, lineLength int) *lineBreaker {
+	return &lineBreaker{
+		lineLength: lineLength,
+		line:       make([]byte, lineLength),
+		used:       0,
+		out:        out,
+	}
+}
+
+func (l *lineBreaker) Write(b []byte) (n int, err os.Error) {
+	n = len(b)
+
+	if n == 0 {
+		return
+	}
+
+	if l.used == 0 && l.haveWritten {
+		_, err = l.out.Write([]byte{'\n'})
+		if err != nil {
+			return
+		}
+	}
+
+	if l.used+len(b) < l.lineLength {
+		l.used += copy(l.line[l.used:], b)
+		return
+	}
+
+	l.haveWritten = true
+	_, err = l.out.Write(l.line[0:l.used])
+	if err != nil {
+		return
+	}
+	excess := l.lineLength - l.used
+	l.used = 0
+
+	_, err = l.out.Write(b[0:excess])
+	if err != nil {
+		return
+	}
+
+	_, err = l.Write(b[excess:])
+	return
+}
+
+func (l *lineBreaker) Close() (err os.Error) {
+	if l.used > 0 {
+		_, err = l.out.Write(l.line[0:l.used])
+		if err != nil {
+			return
+		}
+	}
+
+	return
+}
+
+// encoding keeps track of a running CRC24 over the data which has been written
+// to it and outputs a OpenPGP checksum when closed, followed by an armor
+// trailer.
+//
+// It's built into a stack of io.Writers:
+//    encoding -> base64 encoder -> lineBreaker -> out
+type encoding struct {
+	out       io.Writer
+	breaker   *lineBreaker
+	b64       io.WriteCloser
+	crc       uint32
+	blockType []byte
+}
+
+func (e *encoding) Write(data []byte) (n int, err os.Error) {
+	e.crc = crc24(e.crc, data)
+	return e.b64.Write(data)
+}
+
+func (e *encoding) Close() (err os.Error) {
+	err = e.b64.Close()
+	if err != nil {
+		return
+	}
+	e.breaker.Close()
+
+	var checksumBytes [3]byte
+	checksumBytes[0] = byte(e.crc >> 16)
+	checksumBytes[1] = byte(e.crc >> 8)
+	checksumBytes[2] = byte(e.crc)
+
+	var b64ChecksumBytes [4]byte
+	base64.StdEncoding.Encode(b64ChecksumBytes[:], checksumBytes[:])
+
+	return writeSlices(e.out, blockEnd, b64ChecksumBytes[:], newline, armorEnd, e.blockType, armorEndOfLine)
+}
+
+// Encode returns a WriteCloser which will encode the data written to it in
+// OpenPGP armor.
+func Encode(out io.Writer, blockType string, headers map[string]string) (w io.WriteCloser, err os.Error) {
+	bType := []byte(blockType)
+	err = writeSlices(out, armorStart, bType, armorEndOfLineOut)
+	if err != nil {
+		return
+	}
+
+	for k, v := range headers {
+		err = writeSlices(out, []byte(k), armorHeaderSep, []byte(v), newline)
+		if err != nil {
+			return
+		}
+	}
+
+	_, err = out.Write(newline)
+	if err != nil {
+		return
+	}
+
+	e := &encoding{
+		out:       out,
+		breaker:   newLineBreaker(out, 64),
+		crc:       crc24Init,
+		blockType: bType,
+	}
+	e.b64 = base64.NewEncoder(base64.StdEncoding, e.breaker)
+	return e, nil
+}
diff --git a/src/pkg/crypto/openpgp/canonical_text.go b/src/pkg/crypto/openpgp/canonical_text.go
new file mode 100644
index 000000000..293eff354
--- /dev/null
+++ b/src/pkg/crypto/openpgp/canonical_text.go
@@ -0,0 +1,58 @@
+// Copyright 2011 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package openpgp
+
+import (
+	"hash"
+	"os"
+)
+
+// NewCanonicalTextHash reformats text written to it into the canonical
+// form and then applies the hash h.  See RFC 4880, section 5.2.1.
+func NewCanonicalTextHash(h hash.Hash) hash.Hash {
+	return &canonicalTextHash{h, 0}
+}
+
+type canonicalTextHash struct {
+	h hash.Hash
+	s int
+}
+
+var newline = []byte{'\r', '\n'}
+
+func (cth *canonicalTextHash) Write(buf []byte) (int, os.Error) {
+	start := 0
+
+	for i, c := range buf {
+		switch cth.s {
+		case 0:
+			if c == '\r' {
+				cth.s = 1
+			} else if c == '\n' {
+				cth.h.Write(buf[start:i])
+				cth.h.Write(newline)
+				start = i + 1
+			}
+		case 1:
+			cth.s = 0
+		}
+	}
+
+	cth.h.Write(buf[start:])
+	return len(buf), nil
+}
+
+func (cth *canonicalTextHash) Sum() []byte {
+	return cth.h.Sum()
+}
+
+func (cth *canonicalTextHash) Reset() {
+	cth.h.Reset()
+	cth.s = 0
+}
+
+func (cth *canonicalTextHash) Size() int {
+	return cth.h.Size()
+}
diff --git a/src/pkg/crypto/openpgp/canonical_text_test.go b/src/pkg/crypto/openpgp/canonical_text_test.go
new file mode 100644
index 000000000..ccf2910cc
--- /dev/null
+++ b/src/pkg/crypto/openpgp/canonical_text_test.go
@@ -0,0 +1,49 @@
+// Copyright 2011 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package openpgp
+
+import (
+	"bytes"
+	"os"
+	"testing"
+)
+
+type recordingHash struct {
+	buf *bytes.Buffer
+}
+
+func (r recordingHash) Write(b []byte) (n int, err os.Error) {
+	return r.buf.Write(b)
+}
+
+func (r recordingHash) Sum() []byte {
+	return r.buf.Bytes()
+}
+
+func (r recordingHash) Reset() {
+	panic("shouldn't be called")
+}
+
+func (r recordingHash) Size() int {
+	panic("shouldn't be called")
+}
+
+func testCanonicalText(t *testing.T, input, expected string) {
+	r := recordingHash{bytes.NewBuffer(nil)}
+	c := NewCanonicalTextHash(r)
+	c.Write([]byte(input))
+	result := c.Sum()
+	if expected != string(result) {
+		t.Errorf("input: %x got: %x want: %x", input, result, expected)
+	}
+}
+
+func TestCanonicalText(t *testing.T) {
+	testCanonicalText(t, "foo\n", "foo\r\n")
+	testCanonicalText(t, "foo", "foo")
+	testCanonicalText(t, "foo\r\n", "foo\r\n")
+	testCanonicalText(t, "foo\r\nbar", "foo\r\nbar")
+	testCanonicalText(t, "foo\r\nbar\n\n", "foo\r\nbar\r\n\r\n")
+}
diff --git a/src/pkg/crypto/openpgp/elgamal/Makefile b/src/pkg/crypto/openpgp/elgamal/Makefile
new file mode 100644
index 000000000..f730255f8
--- /dev/null
+++ b/src/pkg/crypto/openpgp/elgamal/Makefile
@@ -0,0 +1,11 @@
+# Copyright 2011 The Go Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style
+# license that can be found in the LICENSE file.
+
+include ../../../../Make.inc
+
+TARG=crypto/openpgp/elgamal
+GOFILES=\
+	elgamal.go\
+
+include ../../../../Make.pkg
diff --git a/src/pkg/crypto/openpgp/elgamal/elgamal.go b/src/pkg/crypto/openpgp/elgamal/elgamal.go
new file mode 100644
index 000000000..99a6e3e1f
--- /dev/null
+++ b/src/pkg/crypto/openpgp/elgamal/elgamal.go
@@ -0,0 +1,122 @@
+// Copyright 2011 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package elgamal implements ElGamal encryption, suitable for OpenPGP,
+// as specified in "A Public-Key Cryptosystem and a Signature Scheme Based on
+// Discrete Logarithms," IEEE Transactions on Information Theory, v. IT-31,
+// n. 4, 1985, pp. 469-472.
+//
+// This form of ElGamal embeds PKCS#1 v1.5 padding, which may make it
+// unsuitable for other protocols. RSA should be used in preference in any
+// case.
+package elgamal
+
+import (
+	"big"
+	"crypto/rand"
+	"crypto/subtle"
+	"io"
+	"os"
+)
+
+// PublicKey represents an ElGamal public key.
+type PublicKey struct {
+	G, P, Y *big.Int
+}
+
+// PrivateKey represents an ElGamal private key.
+type PrivateKey struct {
+	PublicKey
+	X *big.Int
+}
+
+// Encrypt encrypts the given message to the given public key. The result is a
+// pair of integers. Errors can result from reading random, or because msg is
+// too large to be encrypted to the public key.
+func Encrypt(random io.Reader, pub *PublicKey, msg []byte) (c1, c2 *big.Int, err os.Error) {
+	pLen := (pub.P.BitLen() + 7) / 8
+	if len(msg) > pLen-11 {
+		err = os.NewError("elgamal: message too long")
+		return
+	}
+
+	// EM = 0x02 || PS || 0x00 || M
+	em := make([]byte, pLen-1)
+	em[0] = 2
+	ps, mm := em[1:len(em)-len(msg)-1], em[len(em)-len(msg):]
+	err = nonZeroRandomBytes(ps, random)
+	if err != nil {
+		return
+	}
+	em[len(em)-len(msg)-1] = 0
+	copy(mm, msg)
+
+	m := new(big.Int).SetBytes(em)
+
+	k, err := rand.Int(random, pub.P)
+	if err != nil {
+		return
+	}
+
+	c1 = new(big.Int).Exp(pub.G, k, pub.P)
+	s := new(big.Int).Exp(pub.Y, k, pub.P)
+	c2 = s.Mul(s, m)
+	c2.Mod(c2, pub.P)
+
+	return
+}
+
+// Decrypt takes two integers, resulting from an ElGamal encryption, and
+// returns the plaintext of the message. An error can result only if the
+// ciphertext is invalid. Users should keep in mind that this is a padding
+// oracle and thus, if exposed to an adaptive chosen ciphertext attack, can
+// be used to break the cryptosystem.  See ``Chosen Ciphertext Attacks
+// Against Protocols Based on the RSA Encryption Standard PKCS #1'', Daniel
+// Bleichenbacher, Advances in Cryptology (Crypto '98),
+func Decrypt(priv *PrivateKey, c1, c2 *big.Int) (msg []byte, err os.Error) {
+	s := new(big.Int).Exp(c1, priv.X, priv.P)
+	s.ModInverse(s, priv.P)
+	s.Mul(s, c2)
+	s.Mod(s, priv.P)
+	em := s.Bytes()
+
+	firstByteIsTwo := subtle.ConstantTimeByteEq(em[0], 2)
+
+	// The remainder of the plaintext must be a string of non-zero random
+	// octets, followed by a 0, followed by the message.
+	//   lookingForIndex: 1 iff we are still looking for the zero.
+	//   index: the offset of the first zero byte.
+	var lookingForIndex, index int
+	lookingForIndex = 1
+
+	for i := 1; i < len(em); i++ {
+		equals0 := subtle.ConstantTimeByteEq(em[i], 0)
+		index = subtle.ConstantTimeSelect(lookingForIndex&equals0, i, index)
+		lookingForIndex = subtle.ConstantTimeSelect(equals0, 0, lookingForIndex)
+	}
+
+	if firstByteIsTwo != 1 || lookingForIndex != 0 || index < 9 {
+		return nil, os.NewError("elgamal: decryption error")
+	}
+	return em[index+1:], nil
+}
+
+// nonZeroRandomBytes fills the given slice with non-zero random octets.
+func nonZeroRandomBytes(s []byte, rand io.Reader) (err os.Error) {
+	_, err = io.ReadFull(rand, s)
+	if err != nil {
+		return
+	}
+
+	for i := 0; i < len(s); i++ {
+		for s[i] == 0 {
+			_, err = io.ReadFull(rand, s[i:i+1])
+			if err != nil {
+				return
+			}
+		}
+	}
+
+	return
+}
diff --git a/src/pkg/crypto/openpgp/elgamal/elgamal_test.go b/src/pkg/crypto/openpgp/elgamal/elgamal_test.go
new file mode 100644
index 000000000..101121aa6
--- /dev/null
+++ b/src/pkg/crypto/openpgp/elgamal/elgamal_test.go
@@ -0,0 +1,49 @@
+// Copyright 2011 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package elgamal
+
+import (
+	"big"
+	"bytes"
+	"crypto/rand"
+	"testing"
+)
+
+// This is the 1024-bit MODP group from RFC 5114, section 2.1:
+const primeHex = "B10B8F96A080E01DDE92DE5EAE5D54EC52C99FBCFB06A3C69A6A9DCA52D23B616073E28675A23D189838EF1E2EE652C013ECB4AEA906112324975C3CD49B83BFACCBDD7D90C4BD7098488E9C219A73724EFFD6FAE5644738FAA31A4FF55BCCC0A151AF5F0DC8B4BD45BF37DF365C1A65E68CFDA76D4DA708DF1FB2BC2E4A4371"
+
+const generatorHex = "A4D1CBD5C3FD34126765A442EFB99905F8104DD258AC507FD6406CFF14266D31266FEA1E5C41564B777E690F5504F213160217B4B01B886A5E91547F9E2749F4D7FBD7D3B9A92EE1909D0D2263F80A76A6A24C087A091F531DBF0A0169B6A28AD662A4D18E73AFA32D779D5918D08BC8858F4DCEF97C2A24855E6EEB22B3B2E5"
+
+func fromHex(hex string) *big.Int {
+	n, ok := new(big.Int).SetString(hex, 16)
+	if !ok {
+		panic("failed to parse hex number")
+	}
+	return n
+}
+
+func TestEncryptDecrypt(t *testing.T) {
+	priv := &PrivateKey{
+		PublicKey: PublicKey{
+			G: fromHex(generatorHex),
+			P: fromHex(primeHex),
+		},
+		X: fromHex("42"),
+	}
+	priv.Y = new(big.Int).Exp(priv.G, priv.X, priv.P)
+
+	message := []byte("hello world")
+	c1, c2, err := Encrypt(rand.Reader, &priv.PublicKey, message)
+	if err != nil {
+		t.Errorf("error encrypting: %s", err)
+	}
+	message2, err := Decrypt(priv, c1, c2)
+	if err != nil {
+		t.Errorf("error decrypting: %s", err)
+	}
+	if !bytes.Equal(message2, message) {
+		t.Errorf("decryption failed, got: %x, want: %x", message2, message)
+	}
+}
diff --git a/src/pkg/crypto/openpgp/error/Makefile b/src/pkg/crypto/openpgp/error/Makefile
new file mode 100644
index 000000000..8c370a089
--- /dev/null
+++ b/src/pkg/crypto/openpgp/error/Makefile
@@ -0,0 +1,11 @@
+# Copyright 2010 The Go Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style
+# license that can be found in the LICENSE file.
+
+include ../../../../Make.inc
+
+TARG=crypto/openpgp/error
+GOFILES=\
+	error.go\
+
+include ../../../../Make.pkg
diff --git a/src/pkg/crypto/openpgp/error/error.go b/src/pkg/crypto/openpgp/error/error.go
new file mode 100644
index 000000000..3759ce161
--- /dev/null
+++ b/src/pkg/crypto/openpgp/error/error.go
@@ -0,0 +1,64 @@
+// Copyright 2010 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package error contains common error types for the OpenPGP packages.
+package error
+
+import (
+	"strconv"
+)
+
+// A StructuralError is returned when OpenPGP data is found to be syntactically
+// invalid.
+type StructuralError string
+
+func (s StructuralError) String() string {
+	return "OpenPGP data invalid: " + string(s)
+}
+
+// UnsupportedError indicates that, although the OpenPGP data is valid, it
+// makes use of currently unimplemented features.
+type UnsupportedError string
+
+func (s UnsupportedError) String() string {
+	return "OpenPGP feature unsupported: " + string(s)
+}
+
+// InvalidArgumentError indicates that the caller is in error and passed an
+// incorrect value.
+type InvalidArgumentError string
+
+func (i InvalidArgumentError) String() string {
+	return "OpenPGP argument invalid: " + string(i)
+}
+
+// SignatureError indicates that a syntactically valid signature failed to
+// validate.
+type SignatureError string
+
+func (b SignatureError) String() string {
+	return "OpenPGP signature invalid: " + string(b)
+}
+
+type keyIncorrect int
+
+func (ki keyIncorrect) String() string {
+	return "the given key was incorrect"
+}
+
+var KeyIncorrectError = keyIncorrect(0)
+
+type unknownIssuer int
+
+func (unknownIssuer) String() string {
+	return "signature make by unknown entity"
+}
+
+var UnknownIssuerError = unknownIssuer(0)
+
+type UnknownPacketTypeError uint8
+
+func (upte UnknownPacketTypeError) String() string {
+	return "unknown OpenPGP packet type: " + strconv.Itoa(int(upte))
+}
diff --git a/src/pkg/crypto/openpgp/keys.go b/src/pkg/crypto/openpgp/keys.go
new file mode 100644
index 000000000..c70fb7927
--- /dev/null
+++ b/src/pkg/crypto/openpgp/keys.go
@@ -0,0 +1,545 @@
+// Copyright 2011 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package openpgp
+
+import (
+	"crypto"
+	"crypto/openpgp/armor"
+	"crypto/openpgp/error"
+	"crypto/openpgp/packet"
+	"crypto/rsa"
+	"io"
+	"os"
+	"time"
+)
+
+// PublicKeyType is the armor type for a PGP public key.
+var PublicKeyType = "PGP PUBLIC KEY BLOCK"
+// PrivateKeyType is the armor type for a PGP private key.
+var PrivateKeyType = "PGP PRIVATE KEY BLOCK"
+
+// An Entity represents the components of an OpenPGP key: a primary public key
+// (which must be a signing key), one or more identities claimed by that key,
+// and zero or more subkeys, which may be encryption keys.
+type Entity struct {
+	PrimaryKey *packet.PublicKey
+	PrivateKey *packet.PrivateKey
+	Identities map[string]*Identity // indexed by Identity.Name
+	Subkeys    []Subkey
+}
+
+// An Identity represents an identity claimed by an Entity and zero or more
+// assertions by other entities about that claim.
+type Identity struct {
+	Name          string // by convention, has the form "Full Name (comment) <email@example.com>"
+	UserId        *packet.UserId
+	SelfSignature *packet.Signature
+	Signatures    []*packet.Signature
+}
+
+// A Subkey is an additional public key in an Entity. Subkeys can be used for
+// encryption.
+type Subkey struct {
+	PublicKey  *packet.PublicKey
+	PrivateKey *packet.PrivateKey
+	Sig        *packet.Signature
+}
+
+// A Key identifies a specific public key in an Entity. This is either the
+// Entity's primary key or a subkey.
+type Key struct {
+	Entity        *Entity
+	PublicKey     *packet.PublicKey
+	PrivateKey    *packet.PrivateKey
+	SelfSignature *packet.Signature
+}
+
+// A KeyRing provides access to public and private keys.
+type KeyRing interface {
+	// KeysById returns the set of keys that have the given key id.
+	KeysById(id uint64) []Key
+	// DecryptionKeys returns all private keys that are valid for
+	// decryption.
+	DecryptionKeys() []Key
+}
+
+// primaryIdentity returns the Identity marked as primary or the first identity
+// if none are so marked.
+func (e *Entity) primaryIdentity() *Identity {
+	var firstIdentity *Identity
+	for _, ident := range e.Identities {
+		if firstIdentity == nil {
+			firstIdentity = ident
+		}
+		if ident.SelfSignature.IsPrimaryId != nil && *ident.SelfSignature.IsPrimaryId {
+			return ident
+		}
+	}
+	return firstIdentity
+}
+
+// encryptionKey returns the best candidate Key for encrypting a message to the
+// given Entity.
+func (e *Entity) encryptionKey() Key {
+	candidateSubkey := -1
+
+	for i, subkey := range e.Subkeys {
+		if subkey.Sig.FlagsValid && subkey.Sig.FlagEncryptCommunications && subkey.PublicKey.PubKeyAlgo.CanEncrypt() {
+			candidateSubkey = i
+			break
+		}
+	}
+
+	i := e.primaryIdentity()
+
+	if e.PrimaryKey.PubKeyAlgo.CanEncrypt() {
+		// If we don't have any candidate subkeys for encryption and
+		// the primary key doesn't have any usage metadata then we
+		// assume that the primary key is ok. Or, if the primary key is
+		// marked as ok to encrypt to, then we can obviously use it.
+		if candidateSubkey == -1 && !i.SelfSignature.FlagsValid || i.SelfSignature.FlagEncryptCommunications && i.SelfSignature.FlagsValid {
+			return Key{e, e.PrimaryKey, e.PrivateKey, i.SelfSignature}
+		}
+	}
+
+	if candidateSubkey != -1 {
+		subkey := e.Subkeys[candidateSubkey]
+		return Key{e, subkey.PublicKey, subkey.PrivateKey, subkey.Sig}
+	}
+
+	// This Entity appears to be signing only.
+	return Key{}
+}
+
+// signingKey return the best candidate Key for signing a message with this
+// Entity.
+func (e *Entity) signingKey() Key {
+	candidateSubkey := -1
+
+	for i, subkey := range e.Subkeys {
+		if subkey.Sig.FlagsValid && subkey.Sig.FlagSign && subkey.PublicKey.PubKeyAlgo.CanSign() {
+			candidateSubkey = i
+			break
+		}
+	}
+
+	i := e.primaryIdentity()
+
+	// If we have no candidate subkey then we assume that it's ok to sign
+	// with the primary key.
+	if candidateSubkey == -1 || i.SelfSignature.FlagsValid && i.SelfSignature.FlagSign {
+		return Key{e, e.PrimaryKey, e.PrivateKey, i.SelfSignature}
+	}
+
+	subkey := e.Subkeys[candidateSubkey]
+	return Key{e, subkey.PublicKey, subkey.PrivateKey, subkey.Sig}
+}
+
+// An EntityList contains one or more Entities.
+type EntityList []*Entity
+
+// KeysById returns the set of keys that have the given key id.
+func (el EntityList) KeysById(id uint64) (keys []Key) {
+	for _, e := range el {
+		if e.PrimaryKey.KeyId == id {
+			var selfSig *packet.Signature
+			for _, ident := range e.Identities {
+				if selfSig == nil {
+					selfSig = ident.SelfSignature
+				} else if ident.SelfSignature.IsPrimaryId != nil && *ident.SelfSignature.IsPrimaryId {
+					selfSig = ident.SelfSignature
+					break
+				}
+			}
+			keys = append(keys, Key{e, e.PrimaryKey, e.PrivateKey, selfSig})
+		}
+
+		for _, subKey := range e.Subkeys {
+			if subKey.PublicKey.KeyId == id {
+				keys = append(keys, Key{e, subKey.PublicKey, subKey.PrivateKey, subKey.Sig})
+			}
+		}
+	}
+	return
+}
+
+// DecryptionKeys returns all private keys that are valid for decryption.
+func (el EntityList) DecryptionKeys() (keys []Key) {
+	for _, e := range el {
+		for _, subKey := range e.Subkeys {
+			if subKey.PrivateKey != nil && (!subKey.Sig.FlagsValid || subKey.Sig.FlagEncryptStorage || subKey.Sig.FlagEncryptCommunications) {
+				keys = append(keys, Key{e, subKey.PublicKey, subKey.PrivateKey, subKey.Sig})
+			}
+		}
+	}
+	return
+}
+
+// ReadArmoredKeyRing reads one or more public/private keys from an armor keyring file.
+func ReadArmoredKeyRing(r io.Reader) (EntityList, os.Error) {
+	block, err := armor.Decode(r)
+	if err == os.EOF {
+		return nil, error.InvalidArgumentError("no armored data found")
+	}
+	if err != nil {
+		return nil, err
+	}
+	if block.Type != PublicKeyType && block.Type != PrivateKeyType {
+		return nil, error.InvalidArgumentError("expected public or private key block, got: " + block.Type)
+	}
+
+	return ReadKeyRing(block.Body)
+}
+
+// ReadKeyRing reads one or more public/private keys. Unsupported keys are
+// ignored as long as at least a single valid key is found.
+func ReadKeyRing(r io.Reader) (el EntityList, err os.Error) {
+	packets := packet.NewReader(r)
+	var lastUnsupportedError os.Error
+
+	for {
+		var e *Entity
+		e, err = readEntity(packets)
+		if err != nil {
+			if _, ok := err.(error.UnsupportedError); ok {
+				lastUnsupportedError = err
+				err = readToNextPublicKey(packets)
+			}
+			if err == os.EOF {
+				err = nil
+				break
+			}
+			if err != nil {
+				el = nil
+				break
+			}
+		} else {
+			el = append(el, e)
+		}
+	}
+
+	if len(el) == 0 && err == nil {
+		err = lastUnsupportedError
+	}
+	return
+}
+
+// readToNextPublicKey reads packets until the start of the entity and leaves
+// the first packet of the new entity in the Reader.
+func readToNextPublicKey(packets *packet.Reader) (err os.Error) {
+	var p packet.Packet
+	for {
+		p, err = packets.Next()
+		if err == os.EOF {
+			return
+		} else if err != nil {
+			if _, ok := err.(error.UnsupportedError); ok {
+				err = nil
+				continue
+			}
+			return
+		}
+
+		if pk, ok := p.(*packet.PublicKey); ok && !pk.IsSubkey {
+			packets.Unread(p)
+			return
+		}
+	}
+
+	panic("unreachable")
+}
+
+// readEntity reads an entity (public key, identities, subkeys etc) from the
+// given Reader.
+func readEntity(packets *packet.Reader) (*Entity, os.Error) {
+	e := new(Entity)
+	e.Identities = make(map[string]*Identity)
+
+	p, err := packets.Next()
+	if err != nil {
+		return nil, err
+	}
+
+	var ok bool
+	if e.PrimaryKey, ok = p.(*packet.PublicKey); !ok {
+		if e.PrivateKey, ok = p.(*packet.PrivateKey); !ok {
+			packets.Unread(p)
+			return nil, error.StructuralError("first packet was not a public/private key")
+		} else {
+			e.PrimaryKey = &e.PrivateKey.PublicKey
+		}
+	}
+
+	if !e.PrimaryKey.PubKeyAlgo.CanSign() {
+		return nil, error.StructuralError("primary key cannot be used for signatures")
+	}
+
+	var current *Identity
+EachPacket:
+	for {
+		p, err := packets.Next()
+		if err == os.EOF {
+			break
+		} else if err != nil {
+			return nil, err
+		}
+
+		switch pkt := p.(type) {
+		case *packet.UserId:
+			current = new(Identity)
+			current.Name = pkt.Id
+			current.UserId = pkt
+			e.Identities[pkt.Id] = current
+
+			for {
+				p, err = packets.Next()
+				if err == os.EOF {
+					return nil, io.ErrUnexpectedEOF
+				} else if err != nil {
+					return nil, err
+				}
+
+				sig, ok := p.(*packet.Signature)
+				if !ok {
+					return nil, error.StructuralError("user ID packet not followed by self-signature")
+				}
+
+				if (sig.SigType == packet.SigTypePositiveCert || sig.SigType == packet.SigTypeGenericCert) && sig.IssuerKeyId != nil && *sig.IssuerKeyId == e.PrimaryKey.KeyId {
+					if err = e.PrimaryKey.VerifyUserIdSignature(pkt.Id, sig); err != nil {
+						return nil, error.StructuralError("user ID self-signature invalid: " + err.String())
+					}
+					current.SelfSignature = sig
+					break
+				}
+				current.Signatures = append(current.Signatures, sig)
+			}
+		case *packet.Signature:
+			if current == nil {
+				return nil, error.StructuralError("signature packet found before user id packet")
+			}
+			current.Signatures = append(current.Signatures, pkt)
+		case *packet.PrivateKey:
+			if pkt.IsSubkey == false {
+				packets.Unread(p)
+				break EachPacket
+			}
+			err = addSubkey(e, packets, &pkt.PublicKey, pkt)
+			if err != nil {
+				return nil, err
+			}
+		case *packet.PublicKey:
+			if pkt.IsSubkey == false {
+				packets.Unread(p)
+				break EachPacket
+			}
+			err = addSubkey(e, packets, pkt, nil)
+			if err != nil {
+				return nil, err
+			}
+		default:
+			// we ignore unknown packets
+		}
+	}
+
+	if len(e.Identities) == 0 {
+		return nil, error.StructuralError("entity without any identities")
+	}
+
+	return e, nil
+}
+
+func addSubkey(e *Entity, packets *packet.Reader, pub *packet.PublicKey, priv *packet.PrivateKey) os.Error {
+	var subKey Subkey
+	subKey.PublicKey = pub
+	subKey.PrivateKey = priv
+	p, err := packets.Next()
+	if err == os.EOF {
+		return io.ErrUnexpectedEOF
+	}
+	if err != nil {
+		return error.StructuralError("subkey signature invalid: " + err.String())
+	}
+	var ok bool
+	subKey.Sig, ok = p.(*packet.Signature)
+	if !ok {
+		return error.StructuralError("subkey packet not followed by signature")
+	}
+	if subKey.Sig.SigType != packet.SigTypeSubkeyBinding {
+		return error.StructuralError("subkey signature with wrong type")
+	}
+	err = e.PrimaryKey.VerifyKeySignature(subKey.PublicKey, subKey.Sig)
+	if err != nil {
+		return error.StructuralError("subkey signature invalid: " + err.String())
+	}
+	e.Subkeys = append(e.Subkeys, subKey)
+	return nil
+}
+
+const defaultRSAKeyBits = 2048
+
+// NewEntity returns an Entity that contains a fresh RSA/RSA keypair with a
+// single identity composed of the given full name, comment and email, any of
+// which may be empty but must not contain any of "()<>\x00".
+func NewEntity(rand io.Reader, currentTimeSecs int64, name, comment, email string) (*Entity, os.Error) {
+	uid := packet.NewUserId(name, comment, email)
+	if uid == nil {
+		return nil, error.InvalidArgumentError("user id field contained invalid characters")
+	}
+	signingPriv, err := rsa.GenerateKey(rand, defaultRSAKeyBits)
+	if err != nil {
+		return nil, err
+	}
+	encryptingPriv, err := rsa.GenerateKey(rand, defaultRSAKeyBits)
+	if err != nil {
+		return nil, err
+	}
+
+	t := uint32(currentTimeSecs)
+
+	e := &Entity{
+		PrimaryKey: packet.NewRSAPublicKey(t, &signingPriv.PublicKey, false /* not a subkey */ ),
+		PrivateKey: packet.NewRSAPrivateKey(t, signingPriv, false /* not a subkey */ ),
+		Identities: make(map[string]*Identity),
+	}
+	isPrimaryId := true
+	e.Identities[uid.Id] = &Identity{
+		Name:   uid.Name,
+		UserId: uid,
+		SelfSignature: &packet.Signature{
+			CreationTime: t,
+			SigType:      packet.SigTypePositiveCert,
+			PubKeyAlgo:   packet.PubKeyAlgoRSA,
+			Hash:         crypto.SHA256,
+			IsPrimaryId:  &isPrimaryId,
+			FlagsValid:   true,
+			FlagSign:     true,
+			FlagCertify:  true,
+			IssuerKeyId:  &e.PrimaryKey.KeyId,
+		},
+	}
+
+	e.Subkeys = make([]Subkey, 1)
+	e.Subkeys[0] = Subkey{
+		PublicKey:  packet.NewRSAPublicKey(t, &encryptingPriv.PublicKey, true /* is a subkey */ ),
+		PrivateKey: packet.NewRSAPrivateKey(t, encryptingPriv, true /* is a subkey */ ),
+		Sig: &packet.Signature{
+			CreationTime:              t,
+			SigType:                   packet.SigTypeSubkeyBinding,
+			PubKeyAlgo:                packet.PubKeyAlgoRSA,
+			Hash:                      crypto.SHA256,
+			FlagsValid:                true,
+			FlagEncryptStorage:        true,
+			FlagEncryptCommunications: true,
+			IssuerKeyId:               &e.PrimaryKey.KeyId,
+		},
+	}
+
+	return e, nil
+}
+
+// SerializePrivate serializes an Entity, including private key material, to
+// the given Writer. For now, it must only be used on an Entity returned from
+// NewEntity.
+func (e *Entity) SerializePrivate(w io.Writer) (err os.Error) {
+	err = e.PrivateKey.Serialize(w)
+	if err != nil {
+		return
+	}
+	for _, ident := range e.Identities {
+		err = ident.UserId.Serialize(w)
+		if err != nil {
+			return
+		}
+		err = ident.SelfSignature.SignUserId(ident.UserId.Id, e.PrimaryKey, e.PrivateKey)
+		if err != nil {
+			return
+		}
+		err = ident.SelfSignature.Serialize(w)
+		if err != nil {
+			return
+		}
+	}
+	for _, subkey := range e.Subkeys {
+		err = subkey.PrivateKey.Serialize(w)
+		if err != nil {
+			return
+		}
+		err = subkey.Sig.SignKey(subkey.PublicKey, e.PrivateKey)
+		if err != nil {
+			return
+		}
+		err = subkey.Sig.Serialize(w)
+		if err != nil {
+			return
+		}
+	}
+	return nil
+}
+
+// Serialize writes the public part of the given Entity to w. (No private
+// key material will be output).
+func (e *Entity) Serialize(w io.Writer) os.Error {
+	err := e.PrimaryKey.Serialize(w)
+	if err != nil {
+		return err
+	}
+	for _, ident := range e.Identities {
+		err = ident.UserId.Serialize(w)
+		if err != nil {
+			return err
+		}
+		err = ident.SelfSignature.Serialize(w)
+		if err != nil {
+			return err
+		}
+		for _, sig := range ident.Signatures {
+			err = sig.Serialize(w)
+			if err != nil {
+				return err
+			}
+		}
+	}
+	for _, subkey := range e.Subkeys {
+		err = subkey.PublicKey.Serialize(w)
+		if err != nil {
+			return err
+		}
+		err = subkey.Sig.Serialize(w)
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+// SignIdentity adds a signature to e, from signer, attesting that identity is
+// associated with e. The provided identity must already be an element of
+// e.Identities and the private key of signer must have been decrypted if
+// necessary.
+func (e *Entity) SignIdentity(identity string, signer *Entity) os.Error {
+	if signer.PrivateKey == nil {
+		return error.InvalidArgumentError("signing Entity must have a private key")
+	}
+	if signer.PrivateKey.Encrypted {
+		return error.InvalidArgumentError("signing Entity's private key must be decrypted")
+	}
+	ident, ok := e.Identities[identity]
+	if !ok {
+		return error.InvalidArgumentError("given identity string not found in Entity")
+	}
+
+	sig := &packet.Signature{
+		SigType:      packet.SigTypeGenericCert,
+		PubKeyAlgo:   signer.PrivateKey.PubKeyAlgo,
+		Hash:         crypto.SHA256,
+		CreationTime: uint32(time.Seconds()),
+		IssuerKeyId:  &signer.PrivateKey.KeyId,
+	}
+	if err := sig.SignKey(e.PrimaryKey, signer.PrivateKey); err != nil {
+		return err
+	}
+	ident.Signatures = append(ident.Signatures, sig)
+	return nil
+}
diff --git a/src/pkg/crypto/openpgp/packet/Makefile b/src/pkg/crypto/openpgp/packet/Makefile
new file mode 100644
index 000000000..0f0d94eb1
--- /dev/null
+++ b/src/pkg/crypto/openpgp/packet/Makefile
@@ -0,0 +1,22 @@
+# Copyright 2011 The Go Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style
+# license that can be found in the LICENSE file.
+
+include ../../../../Make.inc
+
+TARG=crypto/openpgp/packet
+GOFILES=\
+	compressed.go\
+	encrypted_key.go\
+	literal.go\
+	one_pass_signature.go\
+	packet.go\
+	private_key.go\
+	public_key.go\
+	reader.go\
+	signature.go\
+	symmetrically_encrypted.go\
+	symmetric_key_encrypted.go\
+	userid.go\
+
+include ../../../../Make.pkg
diff --git a/src/pkg/crypto/openpgp/packet/compressed.go b/src/pkg/crypto/openpgp/packet/compressed.go
new file mode 100644
index 000000000..1c15c24c4
--- /dev/null
+++ b/src/pkg/crypto/openpgp/packet/compressed.go
@@ -0,0 +1,39 @@
+// Copyright 2011 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package packet
+
+import (
+	"compress/flate"
+	"compress/zlib"
+	"crypto/openpgp/error"
+	"io"
+	"os"
+	"strconv"
+)
+
+// Compressed represents a compressed OpenPGP packet. The decompressed contents
+// will contain more OpenPGP packets. See RFC 4880, section 5.6.
+type Compressed struct {
+	Body io.Reader
+}
+
+func (c *Compressed) parse(r io.Reader) os.Error {
+	var buf [1]byte
+	_, err := readFull(r, buf[:])
+	if err != nil {
+		return err
+	}
+
+	switch buf[0] {
+	case 1:
+		c.Body = flate.NewReader(r)
+	case 2:
+		c.Body, err = zlib.NewReader(r)
+	default:
+		err = error.UnsupportedError("unknown compression algorithm: " + strconv.Itoa(int(buf[0])))
+	}
+
+	return err
+}
diff --git a/src/pkg/crypto/openpgp/packet/compressed_test.go b/src/pkg/crypto/openpgp/packet/compressed_test.go
new file mode 100644
index 000000000..24fe501ed
--- /dev/null
+++ b/src/pkg/crypto/openpgp/packet/compressed_test.go
@@ -0,0 +1,41 @@
+// Copyright 2011 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package packet
+
+import (
+	"bytes"
+	"encoding/hex"
+	"os"
+	"io/ioutil"
+	"testing"
+)
+
+func TestCompressed(t *testing.T) {
+	packet, err := Read(readerFromHex(compressedHex))
+	if err != nil {
+		t.Errorf("failed to read Compressed: %s", err)
+		return
+	}
+
+	c, ok := packet.(*Compressed)
+	if !ok {
+		t.Error("didn't find Compressed packet")
+		return
+	}
+
+	contents, err := ioutil.ReadAll(c.Body)
+	if err != nil && err != os.EOF {
+		t.Error(err)
+		return
+	}
+
+	expected, _ := hex.DecodeString(compressedExpectedHex)
+	if !bytes.Equal(expected, contents) {
+		t.Errorf("got:%x want:%x", contents, expected)
+	}
+}
+
+const compressedHex = "a3013b2d90c4e02b72e25f727e5e496a5e49b11e1700"
+const compressedExpectedHex = "cb1062004d14c8fe636f6e74656e74732e0a"
diff --git a/src/pkg/crypto/openpgp/packet/encrypted_key.go b/src/pkg/crypto/openpgp/packet/encrypted_key.go
new file mode 100644
index 000000000..b4730cbc9
--- /dev/null
+++ b/src/pkg/crypto/openpgp/packet/encrypted_key.go
@@ -0,0 +1,168 @@
+// Copyright 2011 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package packet
+
+import (
+	"big"
+	"crypto/openpgp/elgamal"
+	"crypto/openpgp/error"
+	"crypto/rand"
+	"crypto/rsa"
+	"encoding/binary"
+	"io"
+	"os"
+	"strconv"
+)
+
+const encryptedKeyVersion = 3
+
+// EncryptedKey represents a public-key encrypted session key. See RFC 4880,
+// section 5.1.
+type EncryptedKey struct {
+	KeyId      uint64
+	Algo       PublicKeyAlgorithm
+	CipherFunc CipherFunction // only valid after a successful Decrypt
+	Key        []byte         // only valid after a successful Decrypt
+
+	encryptedMPI1, encryptedMPI2 []byte
+}
+
+func (e *EncryptedKey) parse(r io.Reader) (err os.Error) {
+	var buf [10]byte
+	_, err = readFull(r, buf[:])
+	if err != nil {
+		return
+	}
+	if buf[0] != encryptedKeyVersion {
+		return error.UnsupportedError("unknown EncryptedKey version " + strconv.Itoa(int(buf[0])))
+	}
+	e.KeyId = binary.BigEndian.Uint64(buf[1:9])
+	e.Algo = PublicKeyAlgorithm(buf[9])
+	switch e.Algo {
+	case PubKeyAlgoRSA, PubKeyAlgoRSAEncryptOnly:
+		e.encryptedMPI1, _, err = readMPI(r)
+	case PubKeyAlgoElGamal:
+		e.encryptedMPI1, _, err = readMPI(r)
+		if err != nil {
+			return
+		}
+		e.encryptedMPI2, _, err = readMPI(r)
+	}
+	_, err = consumeAll(r)
+	return
+}
+
+func checksumKeyMaterial(key []byte) uint16 {
+	var checksum uint16
+	for _, v := range key {
+		checksum += uint16(v)
+	}
+	return checksum
+}
+
+// Decrypt decrypts an encrypted session key with the given private key. The
+// private key must have been decrypted first.
+func (e *EncryptedKey) Decrypt(priv *PrivateKey) os.Error {
+	var err os.Error
+	var b []byte
+
+	// TODO(agl): use session key decryption routines here to avoid
+	// padding oracle attacks.
+	switch priv.PubKeyAlgo {
+	case PubKeyAlgoRSA, PubKeyAlgoRSAEncryptOnly:
+		b, err = rsa.DecryptPKCS1v15(rand.Reader, priv.PrivateKey.(*rsa.PrivateKey), e.encryptedMPI1)
+	case PubKeyAlgoElGamal:
+		c1 := new(big.Int).SetBytes(e.encryptedMPI1)
+		c2 := new(big.Int).SetBytes(e.encryptedMPI2)
+		b, err = elgamal.Decrypt(priv.PrivateKey.(*elgamal.PrivateKey), c1, c2)
+	default:
+		err = error.InvalidArgumentError("cannot decrypted encrypted session key with private key of type " + strconv.Itoa(int(priv.PubKeyAlgo)))
+	}
+
+	if err != nil {
+		return err
+	}
+
+	e.CipherFunc = CipherFunction(b[0])
+	e.Key = b[1 : len(b)-2]
+	expectedChecksum := uint16(b[len(b)-2])<<8 | uint16(b[len(b)-1])
+	checksum := checksumKeyMaterial(e.Key)
+	if checksum != expectedChecksum {
+		return error.StructuralError("EncryptedKey checksum incorrect")
+	}
+
+	return nil
+}
+
+// SerializeEncryptedKey serializes an encrypted key packet to w that contains
+// key, encrypted to pub.
+func SerializeEncryptedKey(w io.Writer, rand io.Reader, pub *PublicKey, cipherFunc CipherFunction, key []byte) os.Error {
+	var buf [10]byte
+	buf[0] = encryptedKeyVersion
+	binary.BigEndian.PutUint64(buf[1:9], pub.KeyId)
+	buf[9] = byte(pub.PubKeyAlgo)
+
+	keyBlock := make([]byte, 1 /* cipher type */ +len(key)+2 /* checksum */ )
+	keyBlock[0] = byte(cipherFunc)
+	copy(keyBlock[1:], key)
+	checksum := checksumKeyMaterial(key)
+	keyBlock[1+len(key)] = byte(checksum >> 8)
+	keyBlock[1+len(key)+1] = byte(checksum)
+
+	switch pub.PubKeyAlgo {
+	case PubKeyAlgoRSA, PubKeyAlgoRSAEncryptOnly:
+		return serializeEncryptedKeyRSA(w, rand, buf, pub.PublicKey.(*rsa.PublicKey), keyBlock)
+	case PubKeyAlgoElGamal:
+		return serializeEncryptedKeyElGamal(w, rand, buf, pub.PublicKey.(*elgamal.PublicKey), keyBlock)
+	case PubKeyAlgoDSA, PubKeyAlgoRSASignOnly:
+		return error.InvalidArgumentError("cannot encrypt to public key of type " + strconv.Itoa(int(pub.PubKeyAlgo)))
+	}
+
+	return error.UnsupportedError("encrypting a key to public key of type " + strconv.Itoa(int(pub.PubKeyAlgo)))
+}
+
+func serializeEncryptedKeyRSA(w io.Writer, rand io.Reader, header [10]byte, pub *rsa.PublicKey, keyBlock []byte) os.Error {
+	cipherText, err := rsa.EncryptPKCS1v15(rand, pub, keyBlock)
+	if err != nil {
+		return error.InvalidArgumentError("RSA encryption failed: " + err.String())
+	}
+
+	packetLen := 10 /* header length */ + 2 /* mpi size */ + len(cipherText)
+
+	err = serializeHeader(w, packetTypeEncryptedKey, packetLen)
+	if err != nil {
+		return err
+	}
+	_, err = w.Write(header[:])
+	if err != nil {
+		return err
+	}
+	return writeMPI(w, 8*uint16(len(cipherText)), cipherText)
+}
+
+func serializeEncryptedKeyElGamal(w io.Writer, rand io.Reader, header [10]byte, pub *elgamal.PublicKey, keyBlock []byte) os.Error {
+	c1, c2, err := elgamal.Encrypt(rand, pub, keyBlock)
+	if err != nil {
+		return error.InvalidArgumentError("ElGamal encryption failed: " + err.String())
+	}
+
+	packetLen := 10 /* header length */
+	packetLen += 2 /* mpi size */ + (c1.BitLen()+7)/8
+	packetLen += 2 /* mpi size */ + (c2.BitLen()+7)/8
+
+	err = serializeHeader(w, packetTypeEncryptedKey, packetLen)
+	if err != nil {
+		return err
+	}
+	_, err = w.Write(header[:])
+	if err != nil {
+		return err
+	}
+	err = writeBig(w, c1)
+	if err != nil {
+		return err
+	}
+	return writeBig(w, c2)
+}
diff --git a/src/pkg/crypto/openpgp/packet/encrypted_key_test.go b/src/pkg/crypto/openpgp/packet/encrypted_key_test.go
new file mode 100644
index 000000000..b402245bd
--- /dev/null
+++ b/src/pkg/crypto/openpgp/packet/encrypted_key_test.go
@@ -0,0 +1,126 @@
+// Copyright 2011 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package packet
+
+import (
+	"big"
+	"bytes"
+	"crypto/rand"
+	"crypto/rsa"
+	"fmt"
+	"testing"
+)
+
+func bigFromBase10(s string) *big.Int {
+	b, ok := new(big.Int).SetString(s, 10)
+	if !ok {
+		panic("bigFromBase10 failed")
+	}
+	return b
+}
+
+var encryptedKeyPub = rsa.PublicKey{
+	E: 65537,
+	N: bigFromBase10("115804063926007623305902631768113868327816898845124614648849934718568541074358183759250136204762053879858102352159854352727097033322663029387610959884180306668628526686121021235757016368038585212410610742029286439607686208110250133174279811431933746643015923132833417396844716207301518956640020862630546868823"),
+}
+
+var encryptedKeyRSAPriv = &rsa.PrivateKey{
+	PublicKey: encryptedKeyPub,
+	D:         bigFromBase10("32355588668219869544751561565313228297765464314098552250409557267371233892496951383426602439009993875125222579159850054973310859166139474359774543943714622292329487391199285040721944491839695981199720170366763547754915493640685849961780092241140181198779299712578774460837139360803883139311171713302987058393"),
+}
+
+var encryptedKeyPriv = &PrivateKey{
+	PublicKey: PublicKey{
+		PubKeyAlgo: PubKeyAlgoRSA,
+	},
+	PrivateKey: encryptedKeyRSAPriv,
+}
+
+func TestDecryptingEncryptedKey(t *testing.T) {
+	const encryptedKeyHex = "c18c032a67d68660df41c70104005789d0de26b6a50c985a02a13131ca829c413a35d0e6fa8d6842599252162808ac7439c72151c8c6183e76923fe3299301414d0c25a2f06a2257db3839e7df0ec964773f6e4c4ac7ff3b48c444237166dd46ba8ff443a5410dc670cb486672fdbe7c9dfafb75b4fea83af3a204fe2a7dfa86bd20122b4f3d2646cbeecb8f7be8"
+	const expectedKeyHex = "d930363f7e0308c333b9618617ea728963d8df993665ae7be1092d4926fd864b"
+
+	p, err := Read(readerFromHex(encryptedKeyHex))
+	if err != nil {
+		t.Errorf("error from Read: %s", err)
+		return
+	}
+	ek, ok := p.(*EncryptedKey)
+	if !ok {
+		t.Errorf("didn't parse an EncryptedKey, got %#v", p)
+		return
+	}
+
+	if ek.KeyId != 0x2a67d68660df41c7 || ek.Algo != PubKeyAlgoRSA {
+		t.Errorf("unexpected EncryptedKey contents: %#v", ek)
+		return
+	}
+
+	err = ek.Decrypt(encryptedKeyPriv)
+	if err != nil {
+		t.Errorf("error from Decrypt: %s", err)
+		return
+	}
+
+	if ek.CipherFunc != CipherAES256 {
+		t.Errorf("unexpected EncryptedKey contents: %#v", ek)
+		return
+	}
+
+	keyHex := fmt.Sprintf("%x", ek.Key)
+	if keyHex != expectedKeyHex {
+		t.Errorf("bad key, got %s want %x", keyHex, expectedKeyHex)
+	}
+}
+
+func TestEncryptingEncryptedKey(t *testing.T) {
+	key := []byte{1, 2, 3, 4}
+	const expectedKeyHex = "01020304"
+	const keyId = 42
+
+	pub := &PublicKey{
+		PublicKey:  &encryptedKeyPub,
+		KeyId:      keyId,
+		PubKeyAlgo: PubKeyAlgoRSAEncryptOnly,
+	}
+
+	buf := new(bytes.Buffer)
+	err := SerializeEncryptedKey(buf, rand.Reader, pub, CipherAES128, key)
+	if err != nil {
+		t.Errorf("error writing encrypted key packet: %s", err)
+	}
+
+	p, err := Read(buf)
+	if err != nil {
+		t.Errorf("error from Read: %s", err)
+		return
+	}
+	ek, ok := p.(*EncryptedKey)
+	if !ok {
+		t.Errorf("didn't parse an EncryptedKey, got %#v", p)
+		return
+	}
+
+	if ek.KeyId != keyId || ek.Algo != PubKeyAlgoRSAEncryptOnly {
+		t.Errorf("unexpected EncryptedKey contents: %#v", ek)
+		return
+	}
+
+	err = ek.Decrypt(encryptedKeyPriv)
+	if err != nil {
+		t.Errorf("error from Decrypt: %s", err)
+		return
+	}
+
+	if ek.CipherFunc != CipherAES128 {
+		t.Errorf("unexpected EncryptedKey contents: %#v", ek)
+		return
+	}
+
+	keyHex := fmt.Sprintf("%x", ek.Key)
+	if keyHex != expectedKeyHex {
+		t.Errorf("bad key, got %s want %x", keyHex, expectedKeyHex)
+	}
+}
diff --git a/src/pkg/crypto/openpgp/packet/literal.go b/src/pkg/crypto/openpgp/packet/literal.go
new file mode 100644
index 000000000..9411572d7
--- /dev/null
+++ b/src/pkg/crypto/openpgp/packet/literal.go
@@ -0,0 +1,90 @@
+// Copyright 2011 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package packet
+
+import (
+	"encoding/binary"
+	"io"
+	"os"
+)
+
+// LiteralData represents an encrypted file. See RFC 4880, section 5.9.
+type LiteralData struct {
+	IsBinary bool
+	FileName string
+	Time     uint32 // Unix epoch time. Either creation time or modification time. 0 means undefined.
+	Body     io.Reader
+}
+
+// ForEyesOnly returns whether the contents of the LiteralData have been marked
+// as especially sensitive.
+func (l *LiteralData) ForEyesOnly() bool {
+	return l.FileName == "_CONSOLE"
+}
+
+func (l *LiteralData) parse(r io.Reader) (err os.Error) {
+	var buf [256]byte
+
+	_, err = readFull(r, buf[:2])
+	if err != nil {
+		return
+	}
+
+	l.IsBinary = buf[0] == 'b'
+	fileNameLen := int(buf[1])
+
+	_, err = readFull(r, buf[:fileNameLen])
+	if err != nil {
+		return
+	}
+
+	l.FileName = string(buf[:fileNameLen])
+
+	_, err = readFull(r, buf[:4])
+	if err != nil {
+		return
+	}
+
+	l.Time = binary.BigEndian.Uint32(buf[:4])
+	l.Body = r
+	return
+}
+
+// SerializeLiteral serializes a literal data packet to w and returns a
+// WriteCloser to which the data itself can be written and which MUST be closed
+// on completion. The fileName is truncated to 255 bytes.
+func SerializeLiteral(w io.WriteCloser, isBinary bool, fileName string, time uint32) (plaintext io.WriteCloser, err os.Error) {
+	var buf [4]byte
+	buf[0] = 't'
+	if isBinary {
+		buf[0] = 'b'
+	}
+	if len(fileName) > 255 {
+		fileName = fileName[:255]
+	}
+	buf[1] = byte(len(fileName))
+
+	inner, err := serializeStreamHeader(w, packetTypeLiteralData)
+	if err != nil {
+		return
+	}
+
+	_, err = inner.Write(buf[:2])
+	if err != nil {
+		return
+	}
+	_, err = inner.Write([]byte(fileName))
+	if err != nil {
+		return
+	}
+	binary.BigEndian.PutUint32(buf[:], time)
+	_, err = inner.Write(buf[:])
+	if err != nil {
+		return
+	}
+
+	plaintext = inner
+	return
+}
diff --git a/src/pkg/crypto/openpgp/packet/one_pass_signature.go b/src/pkg/crypto/openpgp/packet/one_pass_signature.go
new file mode 100644
index 000000000..ca826e4f4
--- /dev/null
+++ b/src/pkg/crypto/openpgp/packet/one_pass_signature.go
@@ -0,0 +1,74 @@
+// Copyright 2011 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package packet
+
+import (
+	"crypto"
+	"crypto/openpgp/error"
+	"crypto/openpgp/s2k"
+	"encoding/binary"
+	"io"
+	"os"
+	"strconv"
+)
+
+// OnePassSignature represents a one-pass signature packet. See RFC 4880,
+// section 5.4.
+type OnePassSignature struct {
+	SigType    SignatureType
+	Hash       crypto.Hash
+	PubKeyAlgo PublicKeyAlgorithm
+	KeyId      uint64
+	IsLast     bool
+}
+
+const onePassSignatureVersion = 3
+
+func (ops *OnePassSignature) parse(r io.Reader) (err os.Error) {
+	var buf [13]byte
+
+	_, err = readFull(r, buf[:])
+	if err != nil {
+		return
+	}
+	if buf[0] != onePassSignatureVersion {
+		err = error.UnsupportedError("one-pass-signature packet version " + strconv.Itoa(int(buf[0])))
+	}
+
+	var ok bool
+	ops.Hash, ok = s2k.HashIdToHash(buf[2])
+	if !ok {
+		return error.UnsupportedError("hash function: " + strconv.Itoa(int(buf[2])))
+	}
+
+	ops.SigType = SignatureType(buf[1])
+	ops.PubKeyAlgo = PublicKeyAlgorithm(buf[3])
+	ops.KeyId = binary.BigEndian.Uint64(buf[4:12])
+	ops.IsLast = buf[12] != 0
+	return
+}
+
+// Serialize marshals the given OnePassSignature to w.
+func (ops *OnePassSignature) Serialize(w io.Writer) os.Error {
+	var buf [13]byte
+	buf[0] = onePassSignatureVersion
+	buf[1] = uint8(ops.SigType)
+	var ok bool
+	buf[2], ok = s2k.HashToHashId(ops.Hash)
+	if !ok {
+		return error.UnsupportedError("hash type: " + strconv.Itoa(int(ops.Hash)))
+	}
+	buf[3] = uint8(ops.PubKeyAlgo)
+	binary.BigEndian.PutUint64(buf[4:12], ops.KeyId)
+	if ops.IsLast {
+		buf[12] = 1
+	}
+
+	if err := serializeHeader(w, packetTypeOnePassSignature, len(buf)); err != nil {
+		return err
+	}
+	_, err := w.Write(buf[:])
+	return err
+}
diff --git a/src/pkg/crypto/openpgp/packet/packet.go b/src/pkg/crypto/openpgp/packet/packet.go
new file mode 100644
index 000000000..1d7297e38
--- /dev/null
+++ b/src/pkg/crypto/openpgp/packet/packet.go
@@ -0,0 +1,483 @@
+// Copyright 2011 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package packet implements parsing and serialization of OpenPGP packets, as
+// specified in RFC 4880.
+package packet
+
+import (
+	"big"
+	"crypto/aes"
+	"crypto/cast5"
+	"crypto/cipher"
+	"crypto/openpgp/error"
+	"io"
+	"os"
+)
+
+// readFull is the same as io.ReadFull except that reading zero bytes returns
+// ErrUnexpectedEOF rather than EOF.
+func readFull(r io.Reader, buf []byte) (n int, err os.Error) {
+	n, err = io.ReadFull(r, buf)
+	if err == os.EOF {
+		err = io.ErrUnexpectedEOF
+	}
+	return
+}
+
+// readLength reads an OpenPGP length from r. See RFC 4880, section 4.2.2.
+func readLength(r io.Reader) (length int64, isPartial bool, err os.Error) {
+	var buf [4]byte
+	_, err = readFull(r, buf[:1])
+	if err != nil {
+		return
+	}
+	switch {
+	case buf[0] < 192:
+		length = int64(buf[0])
+	case buf[0] < 224:
+		length = int64(buf[0]-192) << 8
+		_, err = readFull(r, buf[0:1])
+		if err != nil {
+			return
+		}
+		length += int64(buf[0]) + 192
+	case buf[0] < 255:
+		length = int64(1) << (buf[0] & 0x1f)
+		isPartial = true
+	default:
+		_, err = readFull(r, buf[0:4])
+		if err != nil {
+			return
+		}
+		length = int64(buf[0])<<24 |
+			int64(buf[1])<<16 |
+			int64(buf[2])<<8 |
+			int64(buf[3])
+	}
+	return
+}
+
+// partialLengthReader wraps an io.Reader and handles OpenPGP partial lengths.
+// The continuation lengths are parsed and removed from the stream and EOF is
+// returned at the end of the packet. See RFC 4880, section 4.2.2.4.
+type partialLengthReader struct {
+	r         io.Reader
+	remaining int64
+	isPartial bool
+}
+
+func (r *partialLengthReader) Read(p []byte) (n int, err os.Error) {
+	for r.remaining == 0 {
+		if !r.isPartial {
+			return 0, os.EOF
+		}
+		r.remaining, r.isPartial, err = readLength(r.r)
+		if err != nil {
+			return 0, err
+		}
+	}
+
+	toRead := int64(len(p))
+	if toRead > r.remaining {
+		toRead = r.remaining
+	}
+
+	n, err = r.r.Read(p[:int(toRead)])
+	r.remaining -= int64(n)
+	if n < int(toRead) && err == os.EOF {
+		err = io.ErrUnexpectedEOF
+	}
+	return
+}
+
+// partialLengthWriter writes a stream of data using OpenPGP partial lengths.
+// See RFC 4880, section 4.2.2.4.
+type partialLengthWriter struct {
+	w          io.WriteCloser
+	lengthByte [1]byte
+}
+
+func (w *partialLengthWriter) Write(p []byte) (n int, err os.Error) {
+	for len(p) > 0 {
+		for power := uint(14); power < 32; power-- {
+			l := 1 << power
+			if len(p) >= l {
+				w.lengthByte[0] = 224 + uint8(power)
+				_, err = w.w.Write(w.lengthByte[:])
+				if err != nil {
+					return
+				}
+				var m int
+				m, err = w.w.Write(p[:l])
+				n += m
+				if err != nil {
+					return
+				}
+				p = p[l:]
+				break
+			}
+		}
+	}
+	return
+}
+
+func (w *partialLengthWriter) Close() os.Error {
+	w.lengthByte[0] = 0
+	_, err := w.w.Write(w.lengthByte[:])
+	if err != nil {
+		return err
+	}
+	return w.w.Close()
+}
+
+// A spanReader is an io.LimitReader, but it returns ErrUnexpectedEOF if the
+// underlying Reader returns EOF before the limit has been reached.
+type spanReader struct {
+	r io.Reader
+	n int64
+}
+
+func (l *spanReader) Read(p []byte) (n int, err os.Error) {
+	if l.n <= 0 {
+		return 0, os.EOF
+	}
+	if int64(len(p)) > l.n {
+		p = p[0:l.n]
+	}
+	n, err = l.r.Read(p)
+	l.n -= int64(n)
+	if l.n > 0 && err == os.EOF {
+		err = io.ErrUnexpectedEOF
+	}
+	return
+}
+
+// readHeader parses a packet header and returns an io.Reader which will return
+// the contents of the packet. See RFC 4880, section 4.2.
+func readHeader(r io.Reader) (tag packetType, length int64, contents io.Reader, err os.Error) {
+	var buf [4]byte
+	_, err = io.ReadFull(r, buf[:1])
+	if err != nil {
+		return
+	}
+	if buf[0]&0x80 == 0 {
+		err = error.StructuralError("tag byte does not have MSB set")
+		return
+	}
+	if buf[0]&0x40 == 0 {
+		// Old format packet
+		tag = packetType((buf[0] & 0x3f) >> 2)
+		lengthType := buf[0] & 3
+		if lengthType == 3 {
+			length = -1
+			contents = r
+			return
+		}
+		lengthBytes := 1 << lengthType
+		_, err = readFull(r, buf[0:lengthBytes])
+		if err != nil {
+			return
+		}
+		for i := 0; i < lengthBytes; i++ {
+			length <<= 8
+			length |= int64(buf[i])
+		}
+		contents = &spanReader{r, length}
+		return
+	}
+
+	// New format packet
+	tag = packetType(buf[0] & 0x3f)
+	length, isPartial, err := readLength(r)
+	if err != nil {
+		return
+	}
+	if isPartial {
+		contents = &partialLengthReader{
+			remaining: length,
+			isPartial: true,
+			r:         r,
+		}
+		length = -1
+	} else {
+		contents = &spanReader{r, length}
+	}
+	return
+}
+
+// serializeHeader writes an OpenPGP packet header to w. See RFC 4880, section
+// 4.2.
+func serializeHeader(w io.Writer, ptype packetType, length int) (err os.Error) {
+	var buf [6]byte
+	var n int
+
+	buf[0] = 0x80 | 0x40 | byte(ptype)
+	if length < 192 {
+		buf[1] = byte(length)
+		n = 2
+	} else if length < 8384 {
+		length -= 192
+		buf[1] = 192 + byte(length>>8)
+		buf[2] = byte(length)
+		n = 3
+	} else {
+		buf[1] = 255
+		buf[2] = byte(length >> 24)
+		buf[3] = byte(length >> 16)
+		buf[4] = byte(length >> 8)
+		buf[5] = byte(length)
+		n = 6
+	}
+
+	_, err = w.Write(buf[:n])
+	return
+}
+
+// serializeStreamHeader writes an OpenPGP packet header to w where the
+// length of the packet is unknown. It returns a io.WriteCloser which can be
+// used to write the contents of the packet. See RFC 4880, section 4.2.
+func serializeStreamHeader(w io.WriteCloser, ptype packetType) (out io.WriteCloser, err os.Error) {
+	var buf [1]byte
+	buf[0] = 0x80 | 0x40 | byte(ptype)
+	_, err = w.Write(buf[:])
+	if err != nil {
+		return
+	}
+	out = &partialLengthWriter{w: w}
+	return
+}
+
+// Packet represents an OpenPGP packet. Users are expected to try casting
+// instances of this interface to specific packet types.
+type Packet interface {
+	parse(io.Reader) os.Error
+}
+
+// consumeAll reads from the given Reader until error, returning the number of
+// bytes read.
+func consumeAll(r io.Reader) (n int64, err os.Error) {
+	var m int
+	var buf [1024]byte
+
+	for {
+		m, err = r.Read(buf[:])
+		n += int64(m)
+		if err == os.EOF {
+			err = nil
+			return
+		}
+		if err != nil {
+			return
+		}
+	}
+
+	panic("unreachable")
+}
+
+// packetType represents the numeric ids of the different OpenPGP packet types. See
+// http://www.iana.org/assignments/pgp-parameters/pgp-parameters.xhtml#pgp-parameters-2
+type packetType uint8
+
+const (
+	packetTypeEncryptedKey              packetType = 1
+	packetTypeSignature                 packetType = 2
+	packetTypeSymmetricKeyEncrypted     packetType = 3
+	packetTypeOnePassSignature          packetType = 4
+	packetTypePrivateKey                packetType = 5
+	packetTypePublicKey                 packetType = 6
+	packetTypePrivateSubkey             packetType = 7
+	packetTypeCompressed                packetType = 8
+	packetTypeSymmetricallyEncrypted    packetType = 9
+	packetTypeLiteralData               packetType = 11
+	packetTypeUserId                    packetType = 13
+	packetTypePublicSubkey              packetType = 14
+	packetTypeSymmetricallyEncryptedMDC packetType = 18
+)
+
+// Read reads a single OpenPGP packet from the given io.Reader. If there is an
+// error parsing a packet, the whole packet is consumed from the input.
+func Read(r io.Reader) (p Packet, err os.Error) {
+	tag, _, contents, err := readHeader(r)
+	if err != nil {
+		return
+	}
+
+	switch tag {
+	case packetTypeEncryptedKey:
+		p = new(EncryptedKey)
+	case packetTypeSignature:
+		p = new(Signature)
+	case packetTypeSymmetricKeyEncrypted:
+		p = new(SymmetricKeyEncrypted)
+	case packetTypeOnePassSignature:
+		p = new(OnePassSignature)
+	case packetTypePrivateKey, packetTypePrivateSubkey:
+		pk := new(PrivateKey)
+		if tag == packetTypePrivateSubkey {
+			pk.IsSubkey = true
+		}
+		p = pk
+	case packetTypePublicKey, packetTypePublicSubkey:
+		pk := new(PublicKey)
+		if tag == packetTypePublicSubkey {
+			pk.IsSubkey = true
+		}
+		p = pk
+	case packetTypeCompressed:
+		p = new(Compressed)
+	case packetTypeSymmetricallyEncrypted:
+		p = new(SymmetricallyEncrypted)
+	case packetTypeLiteralData:
+		p = new(LiteralData)
+	case packetTypeUserId:
+		p = new(UserId)
+	case packetTypeSymmetricallyEncryptedMDC:
+		se := new(SymmetricallyEncrypted)
+		se.MDC = true
+		p = se
+	default:
+		err = error.UnknownPacketTypeError(tag)
+	}
+	if p != nil {
+		err = p.parse(contents)
+	}
+	if err != nil {
+		consumeAll(contents)
+	}
+	return
+}
+
+// SignatureType represents the different semantic meanings of an OpenPGP
+// signature. See RFC 4880, section 5.2.1.
+type SignatureType uint8
+
+const (
+	SigTypeBinary        SignatureType = 0
+	SigTypeText                        = 1
+	SigTypeGenericCert                 = 0x10
+	SigTypePersonaCert                 = 0x11
+	SigTypeCasualCert                  = 0x12
+	SigTypePositiveCert                = 0x13
+	SigTypeSubkeyBinding               = 0x18
+)
+
+// PublicKeyAlgorithm represents the different public key system specified for
+// OpenPGP. See
+// http://www.iana.org/assignments/pgp-parameters/pgp-parameters.xhtml#pgp-parameters-12
+type PublicKeyAlgorithm uint8
+
+const (
+	PubKeyAlgoRSA            PublicKeyAlgorithm = 1
+	PubKeyAlgoRSAEncryptOnly PublicKeyAlgorithm = 2
+	PubKeyAlgoRSASignOnly    PublicKeyAlgorithm = 3
+	PubKeyAlgoElGamal        PublicKeyAlgorithm = 16
+	PubKeyAlgoDSA            PublicKeyAlgorithm = 17
+)
+
+// CanEncrypt returns true if it's possible to encrypt a message to a public
+// key of the given type.
+func (pka PublicKeyAlgorithm) CanEncrypt() bool {
+	switch pka {
+	case PubKeyAlgoRSA, PubKeyAlgoRSAEncryptOnly, PubKeyAlgoElGamal:
+		return true
+	}
+	return false
+}
+
+// CanSign returns true if it's possible for a public key of the given type to
+// sign a message.
+func (pka PublicKeyAlgorithm) CanSign() bool {
+	switch pka {
+	case PubKeyAlgoRSA, PubKeyAlgoRSASignOnly, PubKeyAlgoDSA:
+		return true
+	}
+	return false
+}
+
+// CipherFunction represents the different block ciphers specified for OpenPGP. See
+// http://www.iana.org/assignments/pgp-parameters/pgp-parameters.xhtml#pgp-parameters-13
+type CipherFunction uint8
+
+const (
+	CipherCAST5  CipherFunction = 3
+	CipherAES128 CipherFunction = 7
+	CipherAES192 CipherFunction = 8
+	CipherAES256 CipherFunction = 9
+)
+
+// KeySize returns the key size, in bytes, of cipher.
+func (cipher CipherFunction) KeySize() int {
+	switch cipher {
+	case CipherCAST5:
+		return cast5.KeySize
+	case CipherAES128:
+		return 16
+	case CipherAES192:
+		return 24
+	case CipherAES256:
+		return 32
+	}
+	return 0
+}
+
+// blockSize returns the block size, in bytes, of cipher.
+func (cipher CipherFunction) blockSize() int {
+	switch cipher {
+	case CipherCAST5:
+		return 8
+	case CipherAES128, CipherAES192, CipherAES256:
+		return 16
+	}
+	return 0
+}
+
+// new returns a fresh instance of the given cipher.
+func (cipher CipherFunction) new(key []byte) (block cipher.Block) {
+	switch cipher {
+	case CipherCAST5:
+		block, _ = cast5.NewCipher(key)
+	case CipherAES128, CipherAES192, CipherAES256:
+		block, _ = aes.NewCipher(key)
+	}
+	return
+}
+
+// readMPI reads a big integer from r. The bit length returned is the bit
+// length that was specified in r. This is preserved so that the integer can be
+// reserialized exactly.
+func readMPI(r io.Reader) (mpi []byte, bitLength uint16, err os.Error) {
+	var buf [2]byte
+	_, err = readFull(r, buf[0:])
+	if err != nil {
+		return
+	}
+	bitLength = uint16(buf[0])<<8 | uint16(buf[1])
+	numBytes := (int(bitLength) + 7) / 8
+	mpi = make([]byte, numBytes)
+	_, err = readFull(r, mpi)
+	return
+}
+
+// mpiLength returns the length of the given *big.Int when serialized as an
+// MPI.
+func mpiLength(n *big.Int) (mpiLengthInBytes int) {
+	mpiLengthInBytes = 2 /* MPI length */
+	mpiLengthInBytes += (n.BitLen() + 7) / 8
+	return
+}
+
+// writeMPI serializes a big integer to w.
+func writeMPI(w io.Writer, bitLength uint16, mpiBytes []byte) (err os.Error) {
+	_, err = w.Write([]byte{byte(bitLength >> 8), byte(bitLength)})
+	if err == nil {
+		_, err = w.Write(mpiBytes)
+	}
+	return
+}
+
+// writeBig serializes a *big.Int to w.
+func writeBig(w io.Writer, i *big.Int) os.Error {
+	return writeMPI(w, uint16(i.BitLen()), i.Bytes())
+}
diff --git a/src/pkg/crypto/openpgp/packet/packet_test.go b/src/pkg/crypto/openpgp/packet/packet_test.go
new file mode 100644
index 000000000..23d9978ae
--- /dev/null
+++ b/src/pkg/crypto/openpgp/packet/packet_test.go
@@ -0,0 +1,256 @@
+// Copyright 2011 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package packet
+
+import (
+	"bytes"
+	"crypto/openpgp/error"
+	"encoding/hex"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"os"
+	"testing"
+)
+
+func TestReadFull(t *testing.T) {
+	var out [4]byte
+
+	b := bytes.NewBufferString("foo")
+	n, err := readFull(b, out[:3])
+	if n != 3 || err != nil {
+		t.Errorf("full read failed n:%d err:%s", n, err)
+	}
+
+	b = bytes.NewBufferString("foo")
+	n, err = readFull(b, out[:4])
+	if n != 3 || err != io.ErrUnexpectedEOF {
+		t.Errorf("partial read failed n:%d err:%s", n, err)
+	}
+
+	b = bytes.NewBuffer(nil)
+	n, err = readFull(b, out[:3])
+	if n != 0 || err != io.ErrUnexpectedEOF {
+		t.Errorf("empty read failed n:%d err:%s", n, err)
+	}
+}
+
+func readerFromHex(s string) io.Reader {
+	data, err := hex.DecodeString(s)
+	if err != nil {
+		panic("readerFromHex: bad input")
+	}
+	return bytes.NewBuffer(data)
+}
+
+var readLengthTests = []struct {
+	hexInput  string
+	length    int64
+	isPartial bool
+	err       os.Error
+}{
+	{"", 0, false, io.ErrUnexpectedEOF},
+	{"1f", 31, false, nil},
+	{"c0", 0, false, io.ErrUnexpectedEOF},
+	{"c101", 256 + 1 + 192, false, nil},
+	{"e0", 1, true, nil},
+	{"e1", 2, true, nil},
+	{"e2", 4, true, nil},
+	{"ff", 0, false, io.ErrUnexpectedEOF},
+	{"ff00", 0, false, io.ErrUnexpectedEOF},
+	{"ff0000", 0, false, io.ErrUnexpectedEOF},
+	{"ff000000", 0, false, io.ErrUnexpectedEOF},
+	{"ff00000000", 0, false, nil},
+	{"ff01020304", 16909060, false, nil},
+}
+
+func TestReadLength(t *testing.T) {
+	for i, test := range readLengthTests {
+		length, isPartial, err := readLength(readerFromHex(test.hexInput))
+		if test.err != nil {
+			if err != test.err {
+				t.Errorf("%d: expected different error got:%s want:%s", i, err, test.err)
+			}
+			continue
+		}
+		if err != nil {
+			t.Errorf("%d: unexpected error: %s", i, err)
+			continue
+		}
+		if length != test.length || isPartial != test.isPartial {
+			t.Errorf("%d: bad result got:(%d,%t) want:(%d,%t)", i, length, isPartial, test.length, test.isPartial)
+		}
+	}
+}
+
+var partialLengthReaderTests = []struct {
+	hexInput  string
+	err       os.Error
+	hexOutput string
+}{
+	{"e0", io.ErrUnexpectedEOF, ""},
+	{"e001", io.ErrUnexpectedEOF, ""},
+	{"e0010102", nil, "0102"},
+	{"ff00000000", nil, ""},
+	{"e10102e1030400", nil, "01020304"},
+	{"e101", io.ErrUnexpectedEOF, ""},
+}
+
+func TestPartialLengthReader(t *testing.T) {
+	for i, test := range partialLengthReaderTests {
+		r := &partialLengthReader{readerFromHex(test.hexInput), 0, true}
+		out, err := ioutil.ReadAll(r)
+		if test.err != nil {
+			if err != test.err {
+				t.Errorf("%d: expected different error got:%s want:%s", i, err, test.err)
+			}
+			continue
+		}
+		if err != nil {
+			t.Errorf("%d: unexpected error: %s", i, err)
+			continue
+		}
+
+		got := fmt.Sprintf("%x", out)
+		if got != test.hexOutput {
+			t.Errorf("%d: got:%s want:%s", i, test.hexOutput, got)
+		}
+	}
+}
+
+var readHeaderTests = []struct {
+	hexInput        string
+	structuralError bool
+	unexpectedEOF   bool
+	tag             int
+	length          int64
+	hexOutput       string
+}{
+	{"", false, false, 0, 0, ""},
+	{"7f", true, false, 0, 0, ""},
+
+	// Old format headers
+	{"80", false, true, 0, 0, ""},
+	{"8001", false, true, 0, 1, ""},
+	{"800102", false, false, 0, 1, "02"},
+	{"81000102", false, false, 0, 1, "02"},
+	{"820000000102", false, false, 0, 1, "02"},
+	{"860000000102", false, false, 1, 1, "02"},
+	{"83010203", false, false, 0, -1, "010203"},
+
+	// New format headers
+	{"c0", false, true, 0, 0, ""},
+	{"c000", false, false, 0, 0, ""},
+	{"c00102", false, false, 0, 1, "02"},
+	{"c0020203", false, false, 0, 2, "0203"},
+	{"c00202", false, true, 0, 2, ""},
+	{"c3020203", false, false, 3, 2, "0203"},
+}
+
+func TestReadHeader(t *testing.T) {
+	for i, test := range readHeaderTests {
+		tag, length, contents, err := readHeader(readerFromHex(test.hexInput))
+		if test.structuralError {
+			if _, ok := err.(error.StructuralError); ok {
+				continue
+			}
+			t.Errorf("%d: expected StructuralError, got:%s", i, err)
+			continue
+		}
+		if err != nil {
+			if len(test.hexInput) == 0 && err == os.EOF {
+				continue
+			}
+			if !test.unexpectedEOF || err != io.ErrUnexpectedEOF {
+				t.Errorf("%d: unexpected error from readHeader: %s", i, err)
+			}
+			continue
+		}
+		if int(tag) != test.tag || length != test.length {
+			t.Errorf("%d: got:(%d,%d) want:(%d,%d)", i, int(tag), length, test.tag, test.length)
+			continue
+		}
+
+		body, err := ioutil.ReadAll(contents)
+		if err != nil {
+			if !test.unexpectedEOF || err != io.ErrUnexpectedEOF {
+				t.Errorf("%d: unexpected error from contents: %s", i, err)
+			}
+			continue
+		}
+		if test.unexpectedEOF {
+			t.Errorf("%d: expected ErrUnexpectedEOF from contents but got no error", i)
+			continue
+		}
+		got := fmt.Sprintf("%x", body)
+		if got != test.hexOutput {
+			t.Errorf("%d: got:%s want:%s", i, got, test.hexOutput)
+		}
+	}
+}
+
+func TestSerializeHeader(t *testing.T) {
+	tag := packetTypePublicKey
+	lengths := []int{0, 1, 2, 64, 192, 193, 8000, 8384, 8385, 10000}
+
+	for _, length := range lengths {
+		buf := bytes.NewBuffer(nil)
+		serializeHeader(buf, tag, length)
+		tag2, length2, _, err := readHeader(buf)
+		if err != nil {
+			t.Errorf("length %d, err: %s", length, err)
+		}
+		if tag2 != tag {
+			t.Errorf("length %d, tag incorrect (got %d, want %d)", length, tag2, tag)
+		}
+		if int(length2) != length {
+			t.Errorf("length %d, length incorrect (got %d)", length, length2)
+		}
+	}
+}
+
+func TestPartialLengths(t *testing.T) {
+	buf := bytes.NewBuffer(nil)
+	w := new(partialLengthWriter)
+	w.w = noOpCloser{buf}
+
+	const maxChunkSize = 64
+
+	var b [maxChunkSize]byte
+	var n uint8
+	for l := 1; l <= maxChunkSize; l++ {
+		for i := 0; i < l; i++ {
+			b[i] = n
+			n++
+		}
+		m, err := w.Write(b[:l])
+		if m != l {
+			t.Errorf("short write got: %d want: %d", m, l)
+		}
+		if err != nil {
+			t.Errorf("error from write: %s", err)
+		}
+	}
+	w.Close()
+
+	want := (maxChunkSize * (maxChunkSize + 1)) / 2
+	copyBuf := bytes.NewBuffer(nil)
+	r := &partialLengthReader{buf, 0, true}
+	m, err := io.Copy(copyBuf, r)
+	if m != int64(want) {
+		t.Errorf("short copy got: %d want: %d", m, want)
+	}
+	if err != nil {
+		t.Errorf("error from copy: %s", err)
+	}
+
+	copyBytes := copyBuf.Bytes()
+	for i := 0; i < want; i++ {
+		if copyBytes[i] != uint8(i) {
+			t.Errorf("bad pattern in copy at %d", i)
+			break
+		}
+	}
+}
diff --git a/src/pkg/crypto/openpgp/packet/private_key.go b/src/pkg/crypto/openpgp/packet/private_key.go
new file mode 100644
index 000000000..6f8133d98
--- /dev/null
+++ b/src/pkg/crypto/openpgp/packet/private_key.go
@@ -0,0 +1,301 @@
+// Copyright 2011 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package packet
+
+import (
+	"big"
+	"bytes"
+	"crypto/cipher"
+	"crypto/dsa"
+	"crypto/openpgp/elgamal"
+	"crypto/openpgp/error"
+	"crypto/openpgp/s2k"
+	"crypto/rsa"
+	"crypto/sha1"
+	"io"
+	"io/ioutil"
+	"os"
+	"strconv"
+)
+
+// PrivateKey represents a possibly encrypted private key. See RFC 4880,
+// section 5.5.3.
+type PrivateKey struct {
+	PublicKey
+	Encrypted     bool // if true then the private key is unavailable until Decrypt has been called.
+	encryptedData []byte
+	cipher        CipherFunction
+	s2k           func(out, in []byte)
+	PrivateKey    interface{} // An *rsa.PrivateKey.
+	sha1Checksum  bool
+	iv            []byte
+}
+
+func NewRSAPrivateKey(currentTimeSecs uint32, priv *rsa.PrivateKey, isSubkey bool) *PrivateKey {
+	pk := new(PrivateKey)
+	pk.PublicKey = *NewRSAPublicKey(currentTimeSecs, &priv.PublicKey, isSubkey)
+	pk.PrivateKey = priv
+	return pk
+}
+
+func (pk *PrivateKey) parse(r io.Reader) (err os.Error) {
+	err = (&pk.PublicKey).parse(r)
+	if err != nil {
+		return
+	}
+	var buf [1]byte
+	_, err = readFull(r, buf[:])
+	if err != nil {
+		return
+	}
+
+	s2kType := buf[0]
+
+	switch s2kType {
+	case 0:
+		pk.s2k = nil
+		pk.Encrypted = false
+	case 254, 255:
+		_, err = readFull(r, buf[:])
+		if err != nil {
+			return
+		}
+		pk.cipher = CipherFunction(buf[0])
+		pk.Encrypted = true
+		pk.s2k, err = s2k.Parse(r)
+		if err != nil {
+			return
+		}
+		if s2kType == 254 {
+			pk.sha1Checksum = true
+		}
+	default:
+		return error.UnsupportedError("deprecated s2k function in private key")
+	}
+
+	if pk.Encrypted {
+		blockSize := pk.cipher.blockSize()
+		if blockSize == 0 {
+			return error.UnsupportedError("unsupported cipher in private key: " + strconv.Itoa(int(pk.cipher)))
+		}
+		pk.iv = make([]byte, blockSize)
+		_, err = readFull(r, pk.iv)
+		if err != nil {
+			return
+		}
+	}
+
+	pk.encryptedData, err = ioutil.ReadAll(r)
+	if err != nil {
+		return
+	}
+
+	if !pk.Encrypted {
+		return pk.parsePrivateKey(pk.encryptedData)
+	}
+
+	return
+}
+
+func mod64kHash(d []byte) uint16 {
+	h := uint16(0)
+	for i := 0; i < len(d); i += 2 {
+		v := uint16(d[i]) << 8
+		if i+1 < len(d) {
+			v += uint16(d[i+1])
+		}
+		h += v
+	}
+	return h
+}
+
+func (pk *PrivateKey) Serialize(w io.Writer) (err os.Error) {
+	// TODO(agl): support encrypted private keys
+	buf := bytes.NewBuffer(nil)
+	err = pk.PublicKey.serializeWithoutHeaders(buf)
+	if err != nil {
+		return
+	}
+	buf.WriteByte(0 /* no encryption */ )
+
+	privateKeyBuf := bytes.NewBuffer(nil)
+
+	switch priv := pk.PrivateKey.(type) {
+	case *rsa.PrivateKey:
+		err = serializeRSAPrivateKey(privateKeyBuf, priv)
+	default:
+		err = error.InvalidArgumentError("non-RSA private key")
+	}
+	if err != nil {
+		return
+	}
+
+	ptype := packetTypePrivateKey
+	contents := buf.Bytes()
+	privateKeyBytes := privateKeyBuf.Bytes()
+	if pk.IsSubkey {
+		ptype = packetTypePrivateSubkey
+	}
+	err = serializeHeader(w, ptype, len(contents)+len(privateKeyBytes)+2)
+	if err != nil {
+		return
+	}
+	_, err = w.Write(contents)
+	if err != nil {
+		return
+	}
+	_, err = w.Write(privateKeyBytes)
+	if err != nil {
+		return
+	}
+
+	checksum := mod64kHash(privateKeyBytes)
+	var checksumBytes [2]byte
+	checksumBytes[0] = byte(checksum >> 8)
+	checksumBytes[1] = byte(checksum)
+	_, err = w.Write(checksumBytes[:])
+
+	return
+}
+
+func serializeRSAPrivateKey(w io.Writer, priv *rsa.PrivateKey) os.Error {
+	err := writeBig(w, priv.D)
+	if err != nil {
+		return err
+	}
+	err = writeBig(w, priv.Primes[1])
+	if err != nil {
+		return err
+	}
+	err = writeBig(w, priv.Primes[0])
+	if err != nil {
+		return err
+	}
+	return writeBig(w, priv.Precomputed.Qinv)
+}
+
+// Decrypt decrypts an encrypted private key using a passphrase.
+func (pk *PrivateKey) Decrypt(passphrase []byte) os.Error {
+	if !pk.Encrypted {
+		return nil
+	}
+
+	key := make([]byte, pk.cipher.KeySize())
+	pk.s2k(key, passphrase)
+	block := pk.cipher.new(key)
+	cfb := cipher.NewCFBDecrypter(block, pk.iv)
+
+	data := pk.encryptedData
+	cfb.XORKeyStream(data, data)
+
+	if pk.sha1Checksum {
+		if len(data) < sha1.Size {
+			return error.StructuralError("truncated private key data")
+		}
+		h := sha1.New()
+		h.Write(data[:len(data)-sha1.Size])
+		sum := h.Sum()
+		if !bytes.Equal(sum, data[len(data)-sha1.Size:]) {
+			return error.StructuralError("private key checksum failure")
+		}
+		data = data[:len(data)-sha1.Size]
+	} else {
+		if len(data) < 2 {
+			return error.StructuralError("truncated private key data")
+		}
+		var sum uint16
+		for i := 0; i < len(data)-2; i++ {
+			sum += uint16(data[i])
+		}
+		if data[len(data)-2] != uint8(sum>>8) ||
+			data[len(data)-1] != uint8(sum) {
+			return error.StructuralError("private key checksum failure")
+		}
+		data = data[:len(data)-2]
+	}
+
+	return pk.parsePrivateKey(data)
+}
+
+func (pk *PrivateKey) parsePrivateKey(data []byte) (err os.Error) {
+	switch pk.PublicKey.PubKeyAlgo {
+	case PubKeyAlgoRSA, PubKeyAlgoRSASignOnly, PubKeyAlgoRSAEncryptOnly:
+		return pk.parseRSAPrivateKey(data)
+	case PubKeyAlgoDSA:
+		return pk.parseDSAPrivateKey(data)
+	case PubKeyAlgoElGamal:
+		return pk.parseElGamalPrivateKey(data)
+	}
+	panic("impossible")
+}
+
+func (pk *PrivateKey) parseRSAPrivateKey(data []byte) (err os.Error) {
+	rsaPub := pk.PublicKey.PublicKey.(*rsa.PublicKey)
+	rsaPriv := new(rsa.PrivateKey)
+	rsaPriv.PublicKey = *rsaPub
+
+	buf := bytes.NewBuffer(data)
+	d, _, err := readMPI(buf)
+	if err != nil {
+		return
+	}
+	p, _, err := readMPI(buf)
+	if err != nil {
+		return
+	}
+	q, _, err := readMPI(buf)
+	if err != nil {
+		return
+	}
+
+	rsaPriv.D = new(big.Int).SetBytes(d)
+	rsaPriv.Primes = make([]*big.Int, 2)
+	rsaPriv.Primes[0] = new(big.Int).SetBytes(p)
+	rsaPriv.Primes[1] = new(big.Int).SetBytes(q)
+	rsaPriv.Precompute()
+	pk.PrivateKey = rsaPriv
+	pk.Encrypted = false
+	pk.encryptedData = nil
+
+	return nil
+}
+
+func (pk *PrivateKey) parseDSAPrivateKey(data []byte) (err os.Error) {
+	dsaPub := pk.PublicKey.PublicKey.(*dsa.PublicKey)
+	dsaPriv := new(dsa.PrivateKey)
+	dsaPriv.PublicKey = *dsaPub
+
+	buf := bytes.NewBuffer(data)
+	x, _, err := readMPI(buf)
+	if err != nil {
+		return
+	}
+
+	dsaPriv.X = new(big.Int).SetBytes(x)
+	pk.PrivateKey = dsaPriv
+	pk.Encrypted = false
+	pk.encryptedData = nil
+
+	return nil
+}
+
+func (pk *PrivateKey) parseElGamalPrivateKey(data []byte) (err os.Error) {
+	pub := pk.PublicKey.PublicKey.(*elgamal.PublicKey)
+	priv := new(elgamal.PrivateKey)
+	priv.PublicKey = *pub
+
+	buf := bytes.NewBuffer(data)
+	x, _, err := readMPI(buf)
+	if err != nil {
+		return
+	}
+
+	priv.X = new(big.Int).SetBytes(x)
+	pk.PrivateKey = priv
+	pk.Encrypted = false
+	pk.encryptedData = nil
+
+	return nil
+}
diff --git a/src/pkg/crypto/openpgp/packet/private_key_test.go b/src/pkg/crypto/openpgp/packet/private_key_test.go
new file mode 100644
index 000000000..60eebaa6b
--- /dev/null
+++ b/src/pkg/crypto/openpgp/packet/private_key_test.go
@@ -0,0 +1,57 @@
+// Copyright 2011 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package packet
+
+import (
+	"testing"
+)
+
+var privateKeyTests = []struct {
+	privateKeyHex string
+	creationTime  uint32
+}{
+	{
+		privKeyRSAHex,
+		0x4cc349a8,
+	},
+	{
+		privKeyElGamalHex,
+		0x4df9ee1a,
+	},
+}
+
+func TestPrivateKeyRead(t *testing.T) {
+	for i, test := range privateKeyTests {
+		packet, err := Read(readerFromHex(test.privateKeyHex))
+		if err != nil {
+			t.Errorf("#%d: failed to parse: %s", i, err)
+			continue
+		}
+
+		privKey := packet.(*PrivateKey)
+
+		if !privKey.Encrypted {
+			t.Errorf("#%d: private key isn't encrypted", i)
+			continue
+		}
+
+		err = privKey.Decrypt([]byte("testing"))
+		if err != nil {
+			t.Errorf("#%d: failed to decrypt: %s", i, err)
+			continue
+		}
+
+		if privKey.CreationTime != test.creationTime || privKey.Encrypted {
+			t.Errorf("#%d: bad result, got: %#v", i, privKey)
+		}
+	}
+}
+
+// Generated with `gpg --export-secret-keys "Test Key 2"`
+const privKeyRSAHex = "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"
+
+// Generated by `gpg --export-secret-keys` followed by a manual extraction of
+// the ElGamal subkey from the packets.
+const privKeyElGamalHex = "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"
diff --git a/src/pkg/crypto/openpgp/packet/public_key.go b/src/pkg/crypto/openpgp/packet/public_key.go
new file mode 100644
index 000000000..e6b0ae5f3
--- /dev/null
+++ b/src/pkg/crypto/openpgp/packet/public_key.go
@@ -0,0 +1,393 @@
+// Copyright 2011 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package packet
+
+import (
+	"big"
+	"crypto/dsa"
+	"crypto/openpgp/elgamal"
+	"crypto/openpgp/error"
+	"crypto/rsa"
+	"crypto/sha1"
+	"encoding/binary"
+	"fmt"
+	"hash"
+	"io"
+	"os"
+	"strconv"
+)
+
+// PublicKey represents an OpenPGP public key. See RFC 4880, section 5.5.2.
+type PublicKey struct {
+	CreationTime uint32 // seconds since the epoch
+	PubKeyAlgo   PublicKeyAlgorithm
+	PublicKey    interface{} // Either a *rsa.PublicKey or *dsa.PublicKey
+	Fingerprint  [20]byte
+	KeyId        uint64
+	IsSubkey     bool
+
+	n, e, p, q, g, y parsedMPI
+}
+
+func fromBig(n *big.Int) parsedMPI {
+	return parsedMPI{
+		bytes:     n.Bytes(),
+		bitLength: uint16(n.BitLen()),
+	}
+}
+
+// NewRSAPublicKey returns a PublicKey that wraps the given rsa.PublicKey.
+func NewRSAPublicKey(creationTimeSecs uint32, pub *rsa.PublicKey, isSubkey bool) *PublicKey {
+	pk := &PublicKey{
+		CreationTime: creationTimeSecs,
+		PubKeyAlgo:   PubKeyAlgoRSA,
+		PublicKey:    pub,
+		IsSubkey:     isSubkey,
+		n:            fromBig(pub.N),
+		e:            fromBig(big.NewInt(int64(pub.E))),
+	}
+
+	pk.setFingerPrintAndKeyId()
+	return pk
+}
+
+func (pk *PublicKey) parse(r io.Reader) (err os.Error) {
+	// RFC 4880, section 5.5.2
+	var buf [6]byte
+	_, err = readFull(r, buf[:])
+	if err != nil {
+		return
+	}
+	if buf[0] != 4 {
+		return error.UnsupportedError("public key version")
+	}
+	pk.CreationTime = uint32(buf[1])<<24 | uint32(buf[2])<<16 | uint32(buf[3])<<8 | uint32(buf[4])
+	pk.PubKeyAlgo = PublicKeyAlgorithm(buf[5])
+	switch pk.PubKeyAlgo {
+	case PubKeyAlgoRSA, PubKeyAlgoRSAEncryptOnly, PubKeyAlgoRSASignOnly:
+		err = pk.parseRSA(r)
+	case PubKeyAlgoDSA:
+		err = pk.parseDSA(r)
+	case PubKeyAlgoElGamal:
+		err = pk.parseElGamal(r)
+	default:
+		err = error.UnsupportedError("public key type: " + strconv.Itoa(int(pk.PubKeyAlgo)))
+	}
+	if err != nil {
+		return
+	}
+
+	pk.setFingerPrintAndKeyId()
+	return
+}
+
+func (pk *PublicKey) setFingerPrintAndKeyId() {
+	// RFC 4880, section 12.2
+	fingerPrint := sha1.New()
+	pk.SerializeSignaturePrefix(fingerPrint)
+	pk.serializeWithoutHeaders(fingerPrint)
+	copy(pk.Fingerprint[:], fingerPrint.Sum())
+	pk.KeyId = binary.BigEndian.Uint64(pk.Fingerprint[12:20])
+}
+
+// parseRSA parses RSA public key material from the given Reader. See RFC 4880,
+// section 5.5.2.
+func (pk *PublicKey) parseRSA(r io.Reader) (err os.Error) {
+	pk.n.bytes, pk.n.bitLength, err = readMPI(r)
+	if err != nil {
+		return
+	}
+	pk.e.bytes, pk.e.bitLength, err = readMPI(r)
+	if err != nil {
+		return
+	}
+
+	if len(pk.e.bytes) > 3 {
+		err = error.UnsupportedError("large public exponent")
+		return
+	}
+	rsa := &rsa.PublicKey{
+		N: new(big.Int).SetBytes(pk.n.bytes),
+		E: 0,
+	}
+	for i := 0; i < len(pk.e.bytes); i++ {
+		rsa.E <<= 8
+		rsa.E |= int(pk.e.bytes[i])
+	}
+	pk.PublicKey = rsa
+	return
+}
+
+// parseDSA parses DSA public key material from the given Reader. See RFC 4880,
+// section 5.5.2.
+func (pk *PublicKey) parseDSA(r io.Reader) (err os.Error) {
+	pk.p.bytes, pk.p.bitLength, err = readMPI(r)
+	if err != nil {
+		return
+	}
+	pk.q.bytes, pk.q.bitLength, err = readMPI(r)
+	if err != nil {
+		return
+	}
+	pk.g.bytes, pk.g.bitLength, err = readMPI(r)
+	if err != nil {
+		return
+	}
+	pk.y.bytes, pk.y.bitLength, err = readMPI(r)
+	if err != nil {
+		return
+	}
+
+	dsa := new(dsa.PublicKey)
+	dsa.P = new(big.Int).SetBytes(pk.p.bytes)
+	dsa.Q = new(big.Int).SetBytes(pk.q.bytes)
+	dsa.G = new(big.Int).SetBytes(pk.g.bytes)
+	dsa.Y = new(big.Int).SetBytes(pk.y.bytes)
+	pk.PublicKey = dsa
+	return
+}
+
+// parseElGamal parses ElGamal public key material from the given Reader. See
+// RFC 4880, section 5.5.2.
+func (pk *PublicKey) parseElGamal(r io.Reader) (err os.Error) {
+	pk.p.bytes, pk.p.bitLength, err = readMPI(r)
+	if err != nil {
+		return
+	}
+	pk.g.bytes, pk.g.bitLength, err = readMPI(r)
+	if err != nil {
+		return
+	}
+	pk.y.bytes, pk.y.bitLength, err = readMPI(r)
+	if err != nil {
+		return
+	}
+
+	elgamal := new(elgamal.PublicKey)
+	elgamal.P = new(big.Int).SetBytes(pk.p.bytes)
+	elgamal.G = new(big.Int).SetBytes(pk.g.bytes)
+	elgamal.Y = new(big.Int).SetBytes(pk.y.bytes)
+	pk.PublicKey = elgamal
+	return
+}
+
+// SerializeSignaturePrefix writes the prefix for this public key to the given Writer.
+// The prefix is used when calculating a signature over this public key. See
+// RFC 4880, section 5.2.4.
+func (pk *PublicKey) SerializeSignaturePrefix(h hash.Hash) {
+	var pLength uint16
+	switch pk.PubKeyAlgo {
+	case PubKeyAlgoRSA, PubKeyAlgoRSAEncryptOnly, PubKeyAlgoRSASignOnly:
+		pLength += 2 + uint16(len(pk.n.bytes))
+		pLength += 2 + uint16(len(pk.e.bytes))
+	case PubKeyAlgoDSA:
+		pLength += 2 + uint16(len(pk.p.bytes))
+		pLength += 2 + uint16(len(pk.q.bytes))
+		pLength += 2 + uint16(len(pk.g.bytes))
+		pLength += 2 + uint16(len(pk.y.bytes))
+	case PubKeyAlgoElGamal:
+		pLength += 2 + uint16(len(pk.p.bytes))
+		pLength += 2 + uint16(len(pk.g.bytes))
+		pLength += 2 + uint16(len(pk.y.bytes))
+	default:
+		panic("unknown public key algorithm")
+	}
+	pLength += 6
+	h.Write([]byte{0x99, byte(pLength >> 8), byte(pLength)})
+	return
+}
+
+func (pk *PublicKey) Serialize(w io.Writer) (err os.Error) {
+	length := 6 // 6 byte header
+
+	switch pk.PubKeyAlgo {
+	case PubKeyAlgoRSA, PubKeyAlgoRSAEncryptOnly, PubKeyAlgoRSASignOnly:
+		length += 2 + len(pk.n.bytes)
+		length += 2 + len(pk.e.bytes)
+	case PubKeyAlgoDSA:
+		length += 2 + len(pk.p.bytes)
+		length += 2 + len(pk.q.bytes)
+		length += 2 + len(pk.g.bytes)
+		length += 2 + len(pk.y.bytes)
+	case PubKeyAlgoElGamal:
+		length += 2 + len(pk.p.bytes)
+		length += 2 + len(pk.g.bytes)
+		length += 2 + len(pk.y.bytes)
+	default:
+		panic("unknown public key algorithm")
+	}
+
+	packetType := packetTypePublicKey
+	if pk.IsSubkey {
+		packetType = packetTypePublicSubkey
+	}
+	err = serializeHeader(w, packetType, length)
+	if err != nil {
+		return
+	}
+	return pk.serializeWithoutHeaders(w)
+}
+
+// serializeWithoutHeaders marshals the PublicKey to w in the form of an
+// OpenPGP public key packet, not including the packet header.
+func (pk *PublicKey) serializeWithoutHeaders(w io.Writer) (err os.Error) {
+	var buf [6]byte
+	buf[0] = 4
+	buf[1] = byte(pk.CreationTime >> 24)
+	buf[2] = byte(pk.CreationTime >> 16)
+	buf[3] = byte(pk.CreationTime >> 8)
+	buf[4] = byte(pk.CreationTime)
+	buf[5] = byte(pk.PubKeyAlgo)
+
+	_, err = w.Write(buf[:])
+	if err != nil {
+		return
+	}
+
+	switch pk.PubKeyAlgo {
+	case PubKeyAlgoRSA, PubKeyAlgoRSAEncryptOnly, PubKeyAlgoRSASignOnly:
+		return writeMPIs(w, pk.n, pk.e)
+	case PubKeyAlgoDSA:
+		return writeMPIs(w, pk.p, pk.q, pk.g, pk.y)
+	case PubKeyAlgoElGamal:
+		return writeMPIs(w, pk.p, pk.g, pk.y)
+	}
+	return error.InvalidArgumentError("bad public-key algorithm")
+}
+
+// CanSign returns true iff this public key can generate signatures
+func (pk *PublicKey) CanSign() bool {
+	return pk.PubKeyAlgo != PubKeyAlgoRSAEncryptOnly && pk.PubKeyAlgo != PubKeyAlgoElGamal
+}
+
+// VerifySignature returns nil iff sig is a valid signature, made by this
+// public key, of the data hashed into signed. signed is mutated by this call.
+func (pk *PublicKey) VerifySignature(signed hash.Hash, sig *Signature) (err os.Error) {
+	if !pk.CanSign() {
+		return error.InvalidArgumentError("public key cannot generate signatures")
+	}
+
+	signed.Write(sig.HashSuffix)
+	hashBytes := signed.Sum()
+
+	if hashBytes[0] != sig.HashTag[0] || hashBytes[1] != sig.HashTag[1] {
+		return error.SignatureError("hash tag doesn't match")
+	}
+
+	if pk.PubKeyAlgo != sig.PubKeyAlgo {
+		return error.InvalidArgumentError("public key and signature use different algorithms")
+	}
+
+	switch pk.PubKeyAlgo {
+	case PubKeyAlgoRSA, PubKeyAlgoRSASignOnly:
+		rsaPublicKey, _ := pk.PublicKey.(*rsa.PublicKey)
+		err = rsa.VerifyPKCS1v15(rsaPublicKey, sig.Hash, hashBytes, sig.RSASignature.bytes)
+		if err != nil {
+			return error.SignatureError("RSA verification failure")
+		}
+		return nil
+	case PubKeyAlgoDSA:
+		dsaPublicKey, _ := pk.PublicKey.(*dsa.PublicKey)
+		if !dsa.Verify(dsaPublicKey, hashBytes, new(big.Int).SetBytes(sig.DSASigR.bytes), new(big.Int).SetBytes(sig.DSASigS.bytes)) {
+			return error.SignatureError("DSA verification failure")
+		}
+		return nil
+	default:
+		panic("shouldn't happen")
+	}
+	panic("unreachable")
+}
+
+// keySignatureHash returns a Hash of the message that needs to be signed for
+// pk to assert a subkey relationship to signed.
+func keySignatureHash(pk, signed *PublicKey, sig *Signature) (h hash.Hash, err os.Error) {
+	h = sig.Hash.New()
+	if h == nil {
+		return nil, error.UnsupportedError("hash function")
+	}
+
+	// RFC 4880, section 5.2.4
+	pk.SerializeSignaturePrefix(h)
+	pk.serializeWithoutHeaders(h)
+	signed.SerializeSignaturePrefix(h)
+	signed.serializeWithoutHeaders(h)
+	return
+}
+
+// VerifyKeySignature returns nil iff sig is a valid signature, made by this
+// public key, of signed.
+func (pk *PublicKey) VerifyKeySignature(signed *PublicKey, sig *Signature) (err os.Error) {
+	h, err := keySignatureHash(pk, signed, sig)
+	if err != nil {
+		return err
+	}
+	return pk.VerifySignature(h, sig)
+}
+
+// userIdSignatureHash returns a Hash of the message that needs to be signed
+// to assert that pk is a valid key for id.
+func userIdSignatureHash(id string, pk *PublicKey, sig *Signature) (h hash.Hash, err os.Error) {
+	h = sig.Hash.New()
+	if h == nil {
+		return nil, error.UnsupportedError("hash function")
+	}
+
+	// RFC 4880, section 5.2.4
+	pk.SerializeSignaturePrefix(h)
+	pk.serializeWithoutHeaders(h)
+
+	var buf [5]byte
+	buf[0] = 0xb4
+	buf[1] = byte(len(id) >> 24)
+	buf[2] = byte(len(id) >> 16)
+	buf[3] = byte(len(id) >> 8)
+	buf[4] = byte(len(id))
+	h.Write(buf[:])
+	h.Write([]byte(id))
+
+	return
+}
+
+// VerifyUserIdSignature returns nil iff sig is a valid signature, made by this
+// public key, of id.
+func (pk *PublicKey) VerifyUserIdSignature(id string, sig *Signature) (err os.Error) {
+	h, err := userIdSignatureHash(id, pk, sig)
+	if err != nil {
+		return err
+	}
+	return pk.VerifySignature(h, sig)
+}
+
+// KeyIdString returns the public key's fingerprint in capital hex
+// (e.g. "6C7EE1B8621CC013").
+func (pk *PublicKey) KeyIdString() string {
+	return fmt.Sprintf("%X", pk.Fingerprint[12:20])
+}
+
+// KeyIdShortString returns the short form of public key's fingerprint
+// in capital hex, as shown by gpg --list-keys (e.g. "621CC013").
+func (pk *PublicKey) KeyIdShortString() string {
+	return fmt.Sprintf("%X", pk.Fingerprint[16:20])
+}
+
+// A parsedMPI is used to store the contents of a big integer, along with the
+// bit length that was specified in the original input. This allows the MPI to
+// be reserialized exactly.
+type parsedMPI struct {
+	bytes     []byte
+	bitLength uint16
+}
+
+// writeMPIs is a utility function for serializing several big integers to the
+// given Writer.
+func writeMPIs(w io.Writer, mpis ...parsedMPI) (err os.Error) {
+	for _, mpi := range mpis {
+		err = writeMPI(w, mpi.bitLength, mpi.bytes)
+		if err != nil {
+			return
+		}
+	}
+	return
+}
diff --git a/src/pkg/crypto/openpgp/packet/public_key_test.go b/src/pkg/crypto/openpgp/packet/public_key_test.go
new file mode 100644
index 000000000..6e8bfbce6
--- /dev/null
+++ b/src/pkg/crypto/openpgp/packet/public_key_test.go
@@ -0,0 +1,98 @@
+// Copyright 2011 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package packet
+
+import (
+	"bytes"
+	"encoding/hex"
+	"testing"
+)
+
+var pubKeyTests = []struct {
+	hexData        string
+	hexFingerprint string
+	creationTime   uint32
+	pubKeyAlgo     PublicKeyAlgorithm
+	keyId          uint64
+	keyIdString    string
+	keyIdShort     string
+}{
+	{rsaPkDataHex, rsaFingerprintHex, 0x4d3c5c10, PubKeyAlgoRSA, 0xa34d7e18c20c31bb, "A34D7E18C20C31BB", "C20C31BB"},
+	{dsaPkDataHex, dsaFingerprintHex, 0x4d432f89, PubKeyAlgoDSA, 0x8e8fbe54062f19ed, "8E8FBE54062F19ED", "062F19ED"},
+}
+
+func TestPublicKeyRead(t *testing.T) {
+	for i, test := range pubKeyTests {
+		packet, err := Read(readerFromHex(test.hexData))
+		if err != nil {
+			t.Errorf("#%d: Read error: %s", i, err)
+			continue
+		}
+		pk, ok := packet.(*PublicKey)
+		if !ok {
+			t.Errorf("#%d: failed to parse, got: %#v", i, packet)
+			continue
+		}
+		if pk.PubKeyAlgo != test.pubKeyAlgo {
+			t.Errorf("#%d: bad public key algorithm got:%x want:%x", i, pk.PubKeyAlgo, test.pubKeyAlgo)
+		}
+		if pk.CreationTime != test.creationTime {
+			t.Errorf("#%d: bad creation time got:%x want:%x", i, pk.CreationTime, test.creationTime)
+		}
+		expectedFingerprint, _ := hex.DecodeString(test.hexFingerprint)
+		if !bytes.Equal(expectedFingerprint, pk.Fingerprint[:]) {
+			t.Errorf("#%d: bad fingerprint got:%x want:%x", i, pk.Fingerprint[:], expectedFingerprint)
+		}
+		if pk.KeyId != test.keyId {
+			t.Errorf("#%d: bad keyid got:%x want:%x", i, pk.KeyId, test.keyId)
+		}
+		if g, e := pk.KeyIdString(), test.keyIdString; g != e {
+			t.Errorf("#%d: bad KeyIdString got:%q want:%q", i, g, e)
+		}
+		if g, e := pk.KeyIdShortString(), test.keyIdShort; g != e {
+			t.Errorf("#%d: bad KeyIdShortString got:%q want:%q", i, g, e)
+		}
+	}
+}
+
+func TestPublicKeySerialize(t *testing.T) {
+	for i, test := range pubKeyTests {
+		packet, err := Read(readerFromHex(test.hexData))
+		if err != nil {
+			t.Errorf("#%d: Read error: %s", i, err)
+			continue
+		}
+		pk, ok := packet.(*PublicKey)
+		if !ok {
+			t.Errorf("#%d: failed to parse, got: %#v", i, packet)
+			continue
+		}
+		serializeBuf := bytes.NewBuffer(nil)
+		err = pk.Serialize(serializeBuf)
+		if err != nil {
+			t.Errorf("#%d: failed to serialize: %s", i, err)
+			continue
+		}
+
+		packet, err = Read(serializeBuf)
+		if err != nil {
+			t.Errorf("#%d: Read error (from serialized data): %s", i, err)
+			continue
+		}
+		pk, ok = packet.(*PublicKey)
+		if !ok {
+			t.Errorf("#%d: failed to parse serialized data, got: %#v", i, packet)
+			continue
+		}
+	}
+}
+
+const rsaFingerprintHex = "5fb74b1d03b1e3cb31bc2f8aa34d7e18c20c31bb"
+
+const rsaPkDataHex = "988d044d3c5c10010400b1d13382944bd5aba23a4312968b5095d14f947f600eb478e14a6fcb16b0e0cac764884909c020bc495cfcc39a935387c661507bdb236a0612fb582cac3af9b29cc2c8c70090616c41b662f4da4c1201e195472eb7f4ae1ccbcbf9940fe21d985e379a5563dde5b9a23d35f1cfaa5790da3b79db26f23695107bfaca8e7b5bcd0011010001"
+
+const dsaFingerprintHex = "eece4c094db002103714c63c8e8fbe54062f19ed"
+
+const dsaPkDataHex = "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"
diff --git a/src/pkg/crypto/openpgp/packet/reader.go b/src/pkg/crypto/openpgp/packet/reader.go
new file mode 100644
index 000000000..5febc3bc8
--- /dev/null
+++ b/src/pkg/crypto/openpgp/packet/reader.go
@@ -0,0 +1,63 @@
+// Copyright 2011 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package packet
+
+import (
+	"crypto/openpgp/error"
+	"io"
+	"os"
+)
+
+// Reader reads packets from an io.Reader and allows packets to be 'unread' so
+// that they result from the next call to Next.
+type Reader struct {
+	q       []Packet
+	readers []io.Reader
+}
+
+// Next returns the most recently unread Packet, or reads another packet from
+// the top-most io.Reader. Unknown packet types are skipped.
+func (r *Reader) Next() (p Packet, err os.Error) {
+	if len(r.q) > 0 {
+		p = r.q[len(r.q)-1]
+		r.q = r.q[:len(r.q)-1]
+		return
+	}
+
+	for len(r.readers) > 0 {
+		p, err = Read(r.readers[len(r.readers)-1])
+		if err == nil {
+			return
+		}
+		if err == os.EOF {
+			r.readers = r.readers[:len(r.readers)-1]
+			continue
+		}
+		if _, ok := err.(error.UnknownPacketTypeError); !ok {
+			return nil, err
+		}
+	}
+
+	return nil, os.EOF
+}
+
+// Push causes the Reader to start reading from a new io.Reader. When an EOF
+// error is seen from the new io.Reader, it is popped and the Reader continues
+// to read from the next most recent io.Reader.
+func (r *Reader) Push(reader io.Reader) {
+	r.readers = append(r.readers, reader)
+}
+
+// Unread causes the given Packet to be returned from the next call to Next.
+func (r *Reader) Unread(p Packet) {
+	r.q = append(r.q, p)
+}
+
+func NewReader(r io.Reader) *Reader {
+	return &Reader{
+		q:       nil,
+		readers: []io.Reader{r},
+	}
+}
diff --git a/src/pkg/crypto/openpgp/packet/signature.go b/src/pkg/crypto/openpgp/packet/signature.go
new file mode 100644
index 000000000..7577e2875
--- /dev/null
+++ b/src/pkg/crypto/openpgp/packet/signature.go
@@ -0,0 +1,558 @@
+// Copyright 2011 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package packet
+
+import (
+	"crypto"
+	"crypto/dsa"
+	"crypto/openpgp/error"
+	"crypto/openpgp/s2k"
+	"crypto/rand"
+	"crypto/rsa"
+	"encoding/binary"
+	"hash"
+	"io"
+	"os"
+	"strconv"
+)
+
+// Signature represents a signature. See RFC 4880, section 5.2.
+type Signature struct {
+	SigType    SignatureType
+	PubKeyAlgo PublicKeyAlgorithm
+	Hash       crypto.Hash
+
+	// HashSuffix is extra data that is hashed in after the signed data.
+	HashSuffix []byte
+	// HashTag contains the first two bytes of the hash for fast rejection
+	// of bad signed data.
+	HashTag      [2]byte
+	CreationTime uint32 // Unix epoch time
+
+	RSASignature     parsedMPI
+	DSASigR, DSASigS parsedMPI
+
+	// rawSubpackets contains the unparsed subpackets, in order.
+	rawSubpackets []outputSubpacket
+
+	// The following are optional so are nil when not included in the
+	// signature.
+
+	SigLifetimeSecs, KeyLifetimeSecs                        *uint32
+	PreferredSymmetric, PreferredHash, PreferredCompression []uint8
+	IssuerKeyId                                             *uint64
+	IsPrimaryId                                             *bool
+
+	// FlagsValid is set if any flags were given. See RFC 4880, section
+	// 5.2.3.21 for details.
+	FlagsValid                                                           bool
+	FlagCertify, FlagSign, FlagEncryptCommunications, FlagEncryptStorage bool
+
+	outSubpackets []outputSubpacket
+}
+
+func (sig *Signature) parse(r io.Reader) (err os.Error) {
+	// RFC 4880, section 5.2.3
+	var buf [5]byte
+	_, err = readFull(r, buf[:1])
+	if err != nil {
+		return
+	}
+	if buf[0] != 4 {
+		err = error.UnsupportedError("signature packet version " + strconv.Itoa(int(buf[0])))
+		return
+	}
+
+	_, err = readFull(r, buf[:5])
+	if err != nil {
+		return
+	}
+	sig.SigType = SignatureType(buf[0])
+	sig.PubKeyAlgo = PublicKeyAlgorithm(buf[1])
+	switch sig.PubKeyAlgo {
+	case PubKeyAlgoRSA, PubKeyAlgoRSASignOnly, PubKeyAlgoDSA:
+	default:
+		err = error.UnsupportedError("public key algorithm " + strconv.Itoa(int(sig.PubKeyAlgo)))
+		return
+	}
+
+	var ok bool
+	sig.Hash, ok = s2k.HashIdToHash(buf[2])
+	if !ok {
+		return error.UnsupportedError("hash function " + strconv.Itoa(int(buf[2])))
+	}
+
+	hashedSubpacketsLength := int(buf[3])<<8 | int(buf[4])
+	l := 6 + hashedSubpacketsLength
+	sig.HashSuffix = make([]byte, l+6)
+	sig.HashSuffix[0] = 4
+	copy(sig.HashSuffix[1:], buf[:5])
+	hashedSubpackets := sig.HashSuffix[6:l]
+	_, err = readFull(r, hashedSubpackets)
+	if err != nil {
+		return
+	}
+	// See RFC 4880, section 5.2.4
+	trailer := sig.HashSuffix[l:]
+	trailer[0] = 4
+	trailer[1] = 0xff
+	trailer[2] = uint8(l >> 24)
+	trailer[3] = uint8(l >> 16)
+	trailer[4] = uint8(l >> 8)
+	trailer[5] = uint8(l)
+
+	err = parseSignatureSubpackets(sig, hashedSubpackets, true)
+	if err != nil {
+		return
+	}
+
+	_, err = readFull(r, buf[:2])
+	if err != nil {
+		return
+	}
+	unhashedSubpacketsLength := int(buf[0])<<8 | int(buf[1])
+	unhashedSubpackets := make([]byte, unhashedSubpacketsLength)
+	_, err = readFull(r, unhashedSubpackets)
+	if err != nil {
+		return
+	}
+	err = parseSignatureSubpackets(sig, unhashedSubpackets, false)
+	if err != nil {
+		return
+	}
+
+	_, err = readFull(r, sig.HashTag[:2])
+	if err != nil {
+		return
+	}
+
+	switch sig.PubKeyAlgo {
+	case PubKeyAlgoRSA, PubKeyAlgoRSASignOnly:
+		sig.RSASignature.bytes, sig.RSASignature.bitLength, err = readMPI(r)
+	case PubKeyAlgoDSA:
+		sig.DSASigR.bytes, sig.DSASigR.bitLength, err = readMPI(r)
+		if err == nil {
+			sig.DSASigS.bytes, sig.DSASigS.bitLength, err = readMPI(r)
+		}
+	default:
+		panic("unreachable")
+	}
+	return
+}
+
+// parseSignatureSubpackets parses subpackets of the main signature packet. See
+// RFC 4880, section 5.2.3.1.
+func parseSignatureSubpackets(sig *Signature, subpackets []byte, isHashed bool) (err os.Error) {
+	for len(subpackets) > 0 {
+		subpackets, err = parseSignatureSubpacket(sig, subpackets, isHashed)
+		if err != nil {
+			return
+		}
+	}
+
+	if sig.CreationTime == 0 {
+		err = error.StructuralError("no creation time in signature")
+	}
+
+	return
+}
+
+type signatureSubpacketType uint8
+
+const (
+	creationTimeSubpacket        signatureSubpacketType = 2
+	signatureExpirationSubpacket signatureSubpacketType = 3
+	keyExpirySubpacket           signatureSubpacketType = 9
+	prefSymmetricAlgosSubpacket  signatureSubpacketType = 11
+	issuerSubpacket              signatureSubpacketType = 16
+	prefHashAlgosSubpacket       signatureSubpacketType = 21
+	prefCompressionSubpacket     signatureSubpacketType = 22
+	primaryUserIdSubpacket       signatureSubpacketType = 25
+	keyFlagsSubpacket            signatureSubpacketType = 27
+)
+
+// parseSignatureSubpacket parses a single subpacket. len(subpacket) is >= 1.
+func parseSignatureSubpacket(sig *Signature, subpacket []byte, isHashed bool) (rest []byte, err os.Error) {
+	// RFC 4880, section 5.2.3.1
+	var (
+		length     uint32
+		packetType signatureSubpacketType
+		isCritical bool
+	)
+	switch {
+	case subpacket[0] < 192:
+		length = uint32(subpacket[0])
+		subpacket = subpacket[1:]
+	case subpacket[0] < 255:
+		if len(subpacket) < 2 {
+			goto Truncated
+		}
+		length = uint32(subpacket[0]-192)<<8 + uint32(subpacket[1]) + 192
+		subpacket = subpacket[2:]
+	default:
+		if len(subpacket) < 5 {
+			goto Truncated
+		}
+		length = uint32(subpacket[1])<<24 |
+			uint32(subpacket[2])<<16 |
+			uint32(subpacket[3])<<8 |
+			uint32(subpacket[4])
+		subpacket = subpacket[5:]
+	}
+	if length > uint32(len(subpacket)) {
+		goto Truncated
+	}
+	rest = subpacket[length:]
+	subpacket = subpacket[:length]
+	if len(subpacket) == 0 {
+		err = error.StructuralError("zero length signature subpacket")
+		return
+	}
+	packetType = signatureSubpacketType(subpacket[0] & 0x7f)
+	isCritical = subpacket[0]&0x80 == 0x80
+	subpacket = subpacket[1:]
+	sig.rawSubpackets = append(sig.rawSubpackets, outputSubpacket{isHashed, packetType, isCritical, subpacket})
+	switch packetType {
+	case creationTimeSubpacket:
+		if !isHashed {
+			err = error.StructuralError("signature creation time in non-hashed area")
+			return
+		}
+		if len(subpacket) != 4 {
+			err = error.StructuralError("signature creation time not four bytes")
+			return
+		}
+		sig.CreationTime = binary.BigEndian.Uint32(subpacket)
+	case signatureExpirationSubpacket:
+		// Signature expiration time, section 5.2.3.10
+		if !isHashed {
+			return
+		}
+		if len(subpacket) != 4 {
+			err = error.StructuralError("expiration subpacket with bad length")
+			return
+		}
+		sig.SigLifetimeSecs = new(uint32)
+		*sig.SigLifetimeSecs = binary.BigEndian.Uint32(subpacket)
+	case keyExpirySubpacket:
+		// Key expiration time, section 5.2.3.6
+		if !isHashed {
+			return
+		}
+		if len(subpacket) != 4 {
+			err = error.StructuralError("key expiration subpacket with bad length")
+			return
+		}
+		sig.KeyLifetimeSecs = new(uint32)
+		*sig.KeyLifetimeSecs = binary.BigEndian.Uint32(subpacket)
+	case prefSymmetricAlgosSubpacket:
+		// Preferred symmetric algorithms, section 5.2.3.7
+		if !isHashed {
+			return
+		}
+		sig.PreferredSymmetric = make([]byte, len(subpacket))
+		copy(sig.PreferredSymmetric, subpacket)
+	case issuerSubpacket:
+		// Issuer, section 5.2.3.5
+		if len(subpacket) != 8 {
+			err = error.StructuralError("issuer subpacket with bad length")
+			return
+		}
+		sig.IssuerKeyId = new(uint64)
+		*sig.IssuerKeyId = binary.BigEndian.Uint64(subpacket)
+	case prefHashAlgosSubpacket:
+		// Preferred hash algorithms, section 5.2.3.8
+		if !isHashed {
+			return
+		}
+		sig.PreferredHash = make([]byte, len(subpacket))
+		copy(sig.PreferredHash, subpacket)
+	case prefCompressionSubpacket:
+		// Preferred compression algorithms, section 5.2.3.9
+		if !isHashed {
+			return
+		}
+		sig.PreferredCompression = make([]byte, len(subpacket))
+		copy(sig.PreferredCompression, subpacket)
+	case primaryUserIdSubpacket:
+		// Primary User ID, section 5.2.3.19
+		if !isHashed {
+			return
+		}
+		if len(subpacket) != 1 {
+			err = error.StructuralError("primary user id subpacket with bad length")
+			return
+		}
+		sig.IsPrimaryId = new(bool)
+		if subpacket[0] > 0 {
+			*sig.IsPrimaryId = true
+		}
+	case keyFlagsSubpacket:
+		// Key flags, section 5.2.3.21
+		if !isHashed {
+			return
+		}
+		if len(subpacket) == 0 {
+			err = error.StructuralError("empty key flags subpacket")
+			return
+		}
+		sig.FlagsValid = true
+		if subpacket[0]&1 != 0 {
+			sig.FlagCertify = true
+		}
+		if subpacket[0]&2 != 0 {
+			sig.FlagSign = true
+		}
+		if subpacket[0]&4 != 0 {
+			sig.FlagEncryptCommunications = true
+		}
+		if subpacket[0]&8 != 0 {
+			sig.FlagEncryptStorage = true
+		}
+
+	default:
+		if isCritical {
+			err = error.UnsupportedError("unknown critical signature subpacket type " + strconv.Itoa(int(packetType)))
+			return
+		}
+	}
+	return
+
+Truncated:
+	err = error.StructuralError("signature subpacket truncated")
+	return
+}
+
+// subpacketLengthLength returns the length, in bytes, of an encoded length value.
+func subpacketLengthLength(length int) int {
+	if length < 192 {
+		return 1
+	}
+	if length < 16320 {
+		return 2
+	}
+	return 5
+}
+
+// serializeSubpacketLength marshals the given length into to.
+func serializeSubpacketLength(to []byte, length int) int {
+	if length < 192 {
+		to[0] = byte(length)
+		return 1
+	}
+	if length < 16320 {
+		length -= 192
+		to[0] = byte(length >> 8)
+		to[1] = byte(length)
+		return 2
+	}
+	to[0] = 255
+	to[1] = byte(length >> 24)
+	to[2] = byte(length >> 16)
+	to[3] = byte(length >> 8)
+	to[4] = byte(length)
+	return 5
+}
+
+// subpacketsLength returns the serialized length, in bytes, of the given
+// subpackets.
+func subpacketsLength(subpackets []outputSubpacket, hashed bool) (length int) {
+	for _, subpacket := range subpackets {
+		if subpacket.hashed == hashed {
+			length += subpacketLengthLength(len(subpacket.contents) + 1)
+			length += 1 // type byte
+			length += len(subpacket.contents)
+		}
+	}
+	return
+}
+
+// serializeSubpackets marshals the given subpackets into to.
+func serializeSubpackets(to []byte, subpackets []outputSubpacket, hashed bool) {
+	for _, subpacket := range subpackets {
+		if subpacket.hashed == hashed {
+			n := serializeSubpacketLength(to, len(subpacket.contents)+1)
+			to[n] = byte(subpacket.subpacketType)
+			to = to[1+n:]
+			n = copy(to, subpacket.contents)
+			to = to[n:]
+		}
+	}
+	return
+}
+
+// buildHashSuffix constructs the HashSuffix member of sig in preparation for signing.
+func (sig *Signature) buildHashSuffix() (err os.Error) {
+	hashedSubpacketsLen := subpacketsLength(sig.outSubpackets, true)
+
+	var ok bool
+	l := 6 + hashedSubpacketsLen
+	sig.HashSuffix = make([]byte, l+6)
+	sig.HashSuffix[0] = 4
+	sig.HashSuffix[1] = uint8(sig.SigType)
+	sig.HashSuffix[2] = uint8(sig.PubKeyAlgo)
+	sig.HashSuffix[3], ok = s2k.HashToHashId(sig.Hash)
+	if !ok {
+		sig.HashSuffix = nil
+		return error.InvalidArgumentError("hash cannot be represented in OpenPGP: " + strconv.Itoa(int(sig.Hash)))
+	}
+	sig.HashSuffix[4] = byte(hashedSubpacketsLen >> 8)
+	sig.HashSuffix[5] = byte(hashedSubpacketsLen)
+	serializeSubpackets(sig.HashSuffix[6:l], sig.outSubpackets, true)
+	trailer := sig.HashSuffix[l:]
+	trailer[0] = 4
+	trailer[1] = 0xff
+	trailer[2] = byte(l >> 24)
+	trailer[3] = byte(l >> 16)
+	trailer[4] = byte(l >> 8)
+	trailer[5] = byte(l)
+	return
+}
+
+func (sig *Signature) signPrepareHash(h hash.Hash) (digest []byte, err os.Error) {
+	err = sig.buildHashSuffix()
+	if err != nil {
+		return
+	}
+
+	h.Write(sig.HashSuffix)
+	digest = h.Sum()
+	copy(sig.HashTag[:], digest)
+	return
+}
+
+// Sign signs a message with a private key. The hash, h, must contain
+// the hash of the message to be signed and will be mutated by this function.
+// On success, the signature is stored in sig. Call Serialize to write it out.
+func (sig *Signature) Sign(h hash.Hash, priv *PrivateKey) (err os.Error) {
+	sig.outSubpackets = sig.buildSubpackets()
+	digest, err := sig.signPrepareHash(h)
+	if err != nil {
+		return
+	}
+
+	switch priv.PubKeyAlgo {
+	case PubKeyAlgoRSA, PubKeyAlgoRSASignOnly:
+		sig.RSASignature.bytes, err = rsa.SignPKCS1v15(rand.Reader, priv.PrivateKey.(*rsa.PrivateKey), sig.Hash, digest)
+		sig.RSASignature.bitLength = uint16(8 * len(sig.RSASignature.bytes))
+	case PubKeyAlgoDSA:
+		r, s, err := dsa.Sign(rand.Reader, priv.PrivateKey.(*dsa.PrivateKey), digest)
+		if err == nil {
+			sig.DSASigR.bytes = r.Bytes()
+			sig.DSASigR.bitLength = uint16(8 * len(sig.DSASigR.bytes))
+			sig.DSASigS.bytes = s.Bytes()
+			sig.DSASigS.bitLength = uint16(8 * len(sig.DSASigS.bytes))
+		}
+	default:
+		err = error.UnsupportedError("public key algorithm: " + strconv.Itoa(int(sig.PubKeyAlgo)))
+	}
+
+	return
+}
+
+// SignUserId computes a signature from priv, asserting that pub is a valid
+// key for the identity id.  On success, the signature is stored in sig. Call
+// Serialize to write it out.
+func (sig *Signature) SignUserId(id string, pub *PublicKey, priv *PrivateKey) os.Error {
+	h, err := userIdSignatureHash(id, pub, sig)
+	if err != nil {
+		return nil
+	}
+	return sig.Sign(h, priv)
+}
+
+// SignKey computes a signature from priv, asserting that pub is a subkey.  On
+// success, the signature is stored in sig. Call Serialize to write it out.
+func (sig *Signature) SignKey(pub *PublicKey, priv *PrivateKey) os.Error {
+	h, err := keySignatureHash(&priv.PublicKey, pub, sig)
+	if err != nil {
+		return err
+	}
+	return sig.Sign(h, priv)
+}
+
+// Serialize marshals sig to w. SignRSA or SignDSA must have been called first.
+func (sig *Signature) Serialize(w io.Writer) (err os.Error) {
+	if len(sig.outSubpackets) == 0 {
+		sig.outSubpackets = sig.rawSubpackets
+	}
+	if sig.RSASignature.bytes == nil && sig.DSASigR.bytes == nil {
+		return error.InvalidArgumentError("Signature: need to call SignRSA or SignDSA before Serialize")
+	}
+
+	sigLength := 0
+	switch sig.PubKeyAlgo {
+	case PubKeyAlgoRSA, PubKeyAlgoRSASignOnly:
+		sigLength = 2 + len(sig.RSASignature.bytes)
+	case PubKeyAlgoDSA:
+		sigLength = 2 + len(sig.DSASigR.bytes)
+		sigLength += 2 + len(sig.DSASigS.bytes)
+	default:
+		panic("impossible")
+	}
+
+	unhashedSubpacketsLen := subpacketsLength(sig.outSubpackets, false)
+	length := len(sig.HashSuffix) - 6 /* trailer not included */ +
+		2 /* length of unhashed subpackets */ + unhashedSubpacketsLen +
+		2 /* hash tag */ + sigLength
+	err = serializeHeader(w, packetTypeSignature, length)
+	if err != nil {
+		return
+	}
+
+	_, err = w.Write(sig.HashSuffix[:len(sig.HashSuffix)-6])
+	if err != nil {
+		return
+	}
+
+	unhashedSubpackets := make([]byte, 2+unhashedSubpacketsLen)
+	unhashedSubpackets[0] = byte(unhashedSubpacketsLen >> 8)
+	unhashedSubpackets[1] = byte(unhashedSubpacketsLen)
+	serializeSubpackets(unhashedSubpackets[2:], sig.outSubpackets, false)
+
+	_, err = w.Write(unhashedSubpackets)
+	if err != nil {
+		return
+	}
+	_, err = w.Write(sig.HashTag[:])
+	if err != nil {
+		return
+	}
+
+	switch sig.PubKeyAlgo {
+	case PubKeyAlgoRSA, PubKeyAlgoRSASignOnly:
+		err = writeMPIs(w, sig.RSASignature)
+	case PubKeyAlgoDSA:
+		err = writeMPIs(w, sig.DSASigR, sig.DSASigS)
+	default:
+		panic("impossible")
+	}
+	return
+}
+
+// outputSubpacket represents a subpacket to be marshaled.
+type outputSubpacket struct {
+	hashed        bool // true if this subpacket is in the hashed area.
+	subpacketType signatureSubpacketType
+	isCritical    bool
+	contents      []byte
+}
+
+func (sig *Signature) buildSubpackets() (subpackets []outputSubpacket) {
+	creationTime := make([]byte, 4)
+	creationTime[0] = byte(sig.CreationTime >> 24)
+	creationTime[1] = byte(sig.CreationTime >> 16)
+	creationTime[2] = byte(sig.CreationTime >> 8)
+	creationTime[3] = byte(sig.CreationTime)
+	subpackets = append(subpackets, outputSubpacket{true, creationTimeSubpacket, false, creationTime})
+
+	if sig.IssuerKeyId != nil {
+		keyId := make([]byte, 8)
+		binary.BigEndian.PutUint64(keyId, *sig.IssuerKeyId)
+		subpackets = append(subpackets, outputSubpacket{true, issuerSubpacket, false, keyId})
+	}
+
+	return
+}
diff --git a/src/pkg/crypto/openpgp/packet/signature_test.go b/src/pkg/crypto/openpgp/packet/signature_test.go
new file mode 100644
index 000000000..c1bbde8b0
--- /dev/null
+++ b/src/pkg/crypto/openpgp/packet/signature_test.go
@@ -0,0 +1,42 @@
+// Copyright 2011 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package packet
+
+import (
+	"bytes"
+	"crypto"
+	"encoding/hex"
+	"testing"
+)
+
+func TestSignatureRead(t *testing.T) {
+	packet, err := Read(readerFromHex(signatureDataHex))
+	if err != nil {
+		t.Error(err)
+		return
+	}
+	sig, ok := packet.(*Signature)
+	if !ok || sig.SigType != SigTypeBinary || sig.PubKeyAlgo != PubKeyAlgoRSA || sig.Hash != crypto.SHA1 {
+		t.Errorf("failed to parse, got: %#v", packet)
+	}
+}
+
+func TestSignatureReserialize(t *testing.T) {
+	packet, _ := Read(readerFromHex(signatureDataHex))
+	sig := packet.(*Signature)
+	out := new(bytes.Buffer)
+	err := sig.Serialize(out)
+	if err != nil {
+		t.Errorf("error reserializing: %s", err)
+		return
+	}
+
+	expected, _ := hex.DecodeString(signatureDataHex)
+	if !bytes.Equal(expected, out.Bytes()) {
+		t.Errorf("output doesn't match input (got vs expected):\n%s\n%s", hex.Dump(out.Bytes()), hex.Dump(expected))
+	}
+}
+
+const signatureDataHex = "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"
diff --git a/src/pkg/crypto/openpgp/packet/symmetric_key_encrypted.go b/src/pkg/crypto/openpgp/packet/symmetric_key_encrypted.go
new file mode 100644
index 000000000..ad4f1d621
--- /dev/null
+++ b/src/pkg/crypto/openpgp/packet/symmetric_key_encrypted.go
@@ -0,0 +1,162 @@
+// Copyright 2011 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package packet
+
+import (
+	"bytes"
+	"crypto/cipher"
+	"crypto/openpgp/error"
+	"crypto/openpgp/s2k"
+	"io"
+	"os"
+	"strconv"
+)
+
+// This is the largest session key that we'll support. Since no 512-bit cipher
+// has even been seriously used, this is comfortably large.
+const maxSessionKeySizeInBytes = 64
+
+// SymmetricKeyEncrypted represents a passphrase protected session key. See RFC
+// 4880, section 5.3.
+type SymmetricKeyEncrypted struct {
+	CipherFunc   CipherFunction
+	Encrypted    bool
+	Key          []byte // Empty unless Encrypted is false.
+	s2k          func(out, in []byte)
+	encryptedKey []byte
+}
+
+const symmetricKeyEncryptedVersion = 4
+
+func (ske *SymmetricKeyEncrypted) parse(r io.Reader) (err os.Error) {
+	// RFC 4880, section 5.3.
+	var buf [2]byte
+	_, err = readFull(r, buf[:])
+	if err != nil {
+		return
+	}
+	if buf[0] != symmetricKeyEncryptedVersion {
+		return error.UnsupportedError("SymmetricKeyEncrypted version")
+	}
+	ske.CipherFunc = CipherFunction(buf[1])
+
+	if ske.CipherFunc.KeySize() == 0 {
+		return error.UnsupportedError("unknown cipher: " + strconv.Itoa(int(buf[1])))
+	}
+
+	ske.s2k, err = s2k.Parse(r)
+	if err != nil {
+		return
+	}
+
+	encryptedKey := make([]byte, maxSessionKeySizeInBytes)
+	// The session key may follow. We just have to try and read to find
+	// out. If it exists then we limit it to maxSessionKeySizeInBytes.
+	n, err := readFull(r, encryptedKey)
+	if err != nil && err != io.ErrUnexpectedEOF {
+		return
+	}
+	err = nil
+	if n != 0 {
+		if n == maxSessionKeySizeInBytes {
+			return error.UnsupportedError("oversized encrypted session key")
+		}
+		ske.encryptedKey = encryptedKey[:n]
+	}
+
+	ske.Encrypted = true
+
+	return
+}
+
+// Decrypt attempts to decrypt an encrypted session key. If it returns nil,
+// ske.Key will contain the session key.
+func (ske *SymmetricKeyEncrypted) Decrypt(passphrase []byte) os.Error {
+	if !ske.Encrypted {
+		return nil
+	}
+
+	key := make([]byte, ske.CipherFunc.KeySize())
+	ske.s2k(key, passphrase)
+
+	if len(ske.encryptedKey) == 0 {
+		ske.Key = key
+	} else {
+		// the IV is all zeros
+		iv := make([]byte, ske.CipherFunc.blockSize())
+		c := cipher.NewCFBDecrypter(ske.CipherFunc.new(key), iv)
+		c.XORKeyStream(ske.encryptedKey, ske.encryptedKey)
+		ske.CipherFunc = CipherFunction(ske.encryptedKey[0])
+		if ske.CipherFunc.blockSize() == 0 {
+			return error.UnsupportedError("unknown cipher: " + strconv.Itoa(int(ske.CipherFunc)))
+		}
+		ske.CipherFunc = CipherFunction(ske.encryptedKey[0])
+		ske.Key = ske.encryptedKey[1:]
+		if len(ske.Key)%ske.CipherFunc.blockSize() != 0 {
+			ske.Key = nil
+			return error.StructuralError("length of decrypted key not a multiple of block size")
+		}
+	}
+
+	ske.Encrypted = false
+	return nil
+}
+
+// SerializeSymmetricKeyEncrypted serializes a symmetric key packet to w. The
+// packet contains a random session key, encrypted by a key derived from the
+// given passphrase. The session key is returned and must be passed to
+// SerializeSymmetricallyEncrypted.
+func SerializeSymmetricKeyEncrypted(w io.Writer, rand io.Reader, passphrase []byte, cipherFunc CipherFunction) (key []byte, err os.Error) {
+	keySize := cipherFunc.KeySize()
+	if keySize == 0 {
+		return nil, error.UnsupportedError("unknown cipher: " + strconv.Itoa(int(cipherFunc)))
+	}
+
+	s2kBuf := new(bytes.Buffer)
+	keyEncryptingKey := make([]byte, keySize)
+	// s2k.Serialize salts and stretches the passphrase, and writes the
+	// resulting key to keyEncryptingKey and the s2k descriptor to s2kBuf.
+	err = s2k.Serialize(s2kBuf, keyEncryptingKey, rand, passphrase)
+	if err != nil {
+		return
+	}
+	s2kBytes := s2kBuf.Bytes()
+
+	packetLength := 2 /* header */ + len(s2kBytes) + 1 /* cipher type */ + keySize
+	err = serializeHeader(w, packetTypeSymmetricKeyEncrypted, packetLength)
+	if err != nil {
+		return
+	}
+
+	var buf [2]byte
+	buf[0] = symmetricKeyEncryptedVersion
+	buf[1] = byte(cipherFunc)
+	_, err = w.Write(buf[:])
+	if err != nil {
+		return
+	}
+	_, err = w.Write(s2kBytes)
+	if err != nil {
+		return
+	}
+
+	sessionKey := make([]byte, keySize)
+	_, err = io.ReadFull(rand, sessionKey)
+	if err != nil {
+		return
+	}
+	iv := make([]byte, cipherFunc.blockSize())
+	c := cipher.NewCFBEncrypter(cipherFunc.new(keyEncryptingKey), iv)
+	encryptedCipherAndKey := make([]byte, keySize+1)
+	c.XORKeyStream(encryptedCipherAndKey, buf[1:])
+	c.XORKeyStream(encryptedCipherAndKey[1:], sessionKey)
+	_, err = w.Write(encryptedCipherAndKey)
+	if err != nil {
+		return
+	}
+
+	key = sessionKey
+	return
+}
diff --git a/src/pkg/crypto/openpgp/packet/symmetric_key_encrypted_test.go b/src/pkg/crypto/openpgp/packet/symmetric_key_encrypted_test.go
new file mode 100644
index 000000000..823ec400d
--- /dev/null
+++ b/src/pkg/crypto/openpgp/packet/symmetric_key_encrypted_test.go
@@ -0,0 +1,101 @@
+// Copyright 2011 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package packet
+
+import (
+	"bytes"
+	"crypto/rand"
+	"encoding/hex"
+	"io/ioutil"
+	"os"
+	"testing"
+)
+
+func TestSymmetricKeyEncrypted(t *testing.T) {
+	buf := readerFromHex(symmetricallyEncryptedHex)
+	packet, err := Read(buf)
+	if err != nil {
+		t.Errorf("failed to read SymmetricKeyEncrypted: %s", err)
+		return
+	}
+	ske, ok := packet.(*SymmetricKeyEncrypted)
+	if !ok {
+		t.Error("didn't find SymmetricKeyEncrypted packet")
+		return
+	}
+	err = ske.Decrypt([]byte("password"))
+	if err != nil {
+		t.Error(err)
+		return
+	}
+
+	packet, err = Read(buf)
+	if err != nil {
+		t.Errorf("failed to read SymmetricallyEncrypted: %s", err)
+		return
+	}
+	se, ok := packet.(*SymmetricallyEncrypted)
+	if !ok {
+		t.Error("didn't find SymmetricallyEncrypted packet")
+		return
+	}
+	r, err := se.Decrypt(ske.CipherFunc, ske.Key)
+	if err != nil {
+		t.Error(err)
+		return
+	}
+
+	contents, err := ioutil.ReadAll(r)
+	if err != nil && err != os.EOF {
+		t.Error(err)
+		return
+	}
+
+	expectedContents, _ := hex.DecodeString(symmetricallyEncryptedContentsHex)
+	if !bytes.Equal(expectedContents, contents) {
+		t.Errorf("bad contents got:%x want:%x", contents, expectedContents)
+	}
+}
+
+const symmetricallyEncryptedHex = "8c0d04030302371a0b38d884f02060c91cf97c9973b8e58e028e9501708ccfe618fb92afef7fa2d80ddadd93cf"
+const symmetricallyEncryptedContentsHex = "cb1062004d14c4df636f6e74656e74732e0a"
+
+func TestSerializeSymmetricKeyEncrypted(t *testing.T) {
+	buf := bytes.NewBuffer(nil)
+	passphrase := []byte("testing")
+	cipherFunc := CipherAES128
+
+	key, err := SerializeSymmetricKeyEncrypted(buf, rand.Reader, passphrase, cipherFunc)
+	if err != nil {
+		t.Errorf("failed to serialize: %s", err)
+		return
+	}
+
+	p, err := Read(buf)
+	if err != nil {
+		t.Errorf("failed to reparse: %s", err)
+		return
+	}
+	ske, ok := p.(*SymmetricKeyEncrypted)
+	if !ok {
+		t.Errorf("parsed a different packet type: %#v", p)
+		return
+	}
+
+	if !ske.Encrypted {
+		t.Errorf("SKE not encrypted but should be")
+	}
+	if ske.CipherFunc != cipherFunc {
+		t.Errorf("SKE cipher function is %d (expected %d)", ske.CipherFunc, cipherFunc)
+	}
+	err = ske.Decrypt(passphrase)
+	if err != nil {
+		t.Errorf("failed to decrypt reparsed SKE: %s", err)
+		return
+	}
+	if !bytes.Equal(key, ske.Key) {
+		t.Errorf("keys don't match after Decrpyt: %x (original) vs %x (parsed)", key, ske.Key)
+	}
+}
diff --git a/src/pkg/crypto/openpgp/packet/symmetrically_encrypted.go b/src/pkg/crypto/openpgp/packet/symmetrically_encrypted.go
new file mode 100644
index 000000000..e33c9f3a0
--- /dev/null
+++ b/src/pkg/crypto/openpgp/packet/symmetrically_encrypted.go
@@ -0,0 +1,291 @@
+// Copyright 2011 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package packet
+
+import (
+	"crypto/cipher"
+	"crypto/openpgp/error"
+	"crypto/rand"
+	"crypto/sha1"
+	"crypto/subtle"
+	"hash"
+	"io"
+	"os"
+	"strconv"
+)
+
+// SymmetricallyEncrypted represents a symmetrically encrypted byte string. The
+// encrypted contents will consist of more OpenPGP packets. See RFC 4880,
+// sections 5.7 and 5.13.
+type SymmetricallyEncrypted struct {
+	MDC      bool // true iff this is a type 18 packet and thus has an embedded MAC.
+	contents io.Reader
+	prefix   []byte
+}
+
+const symmetricallyEncryptedVersion = 1
+
+func (se *SymmetricallyEncrypted) parse(r io.Reader) os.Error {
+	if se.MDC {
+		// See RFC 4880, section 5.13.
+		var buf [1]byte
+		_, err := readFull(r, buf[:])
+		if err != nil {
+			return err
+		}
+		if buf[0] != symmetricallyEncryptedVersion {
+			return error.UnsupportedError("unknown SymmetricallyEncrypted version")
+		}
+	}
+	se.contents = r
+	return nil
+}
+
+// Decrypt returns a ReadCloser, from which the decrypted contents of the
+// packet can be read. An incorrect key can, with high probability, be detected
+// immediately and this will result in a KeyIncorrect error being returned.
+func (se *SymmetricallyEncrypted) Decrypt(c CipherFunction, key []byte) (io.ReadCloser, os.Error) {
+	keySize := c.KeySize()
+	if keySize == 0 {
+		return nil, error.UnsupportedError("unknown cipher: " + strconv.Itoa(int(c)))
+	}
+	if len(key) != keySize {
+		return nil, error.InvalidArgumentError("SymmetricallyEncrypted: incorrect key length")
+	}
+
+	if se.prefix == nil {
+		se.prefix = make([]byte, c.blockSize()+2)
+		_, err := readFull(se.contents, se.prefix)
+		if err != nil {
+			return nil, err
+		}
+	} else if len(se.prefix) != c.blockSize()+2 {
+		return nil, error.InvalidArgumentError("can't try ciphers with different block lengths")
+	}
+
+	ocfbResync := cipher.OCFBResync
+	if se.MDC {
+		// MDC packets use a different form of OCFB mode.
+		ocfbResync = cipher.OCFBNoResync
+	}
+
+	s := cipher.NewOCFBDecrypter(c.new(key), se.prefix, ocfbResync)
+	if s == nil {
+		return nil, error.KeyIncorrectError
+	}
+
+	plaintext := cipher.StreamReader{S: s, R: se.contents}
+
+	if se.MDC {
+		// MDC packets have an embedded hash that we need to check.
+		h := sha1.New()
+		h.Write(se.prefix)
+		return &seMDCReader{in: plaintext, h: h}, nil
+	}
+
+	// Otherwise, we just need to wrap plaintext so that it's a valid ReadCloser.
+	return seReader{plaintext}, nil
+}
+
+// seReader wraps an io.Reader with a no-op Close method.
+type seReader struct {
+	in io.Reader
+}
+
+func (ser seReader) Read(buf []byte) (int, os.Error) {
+	return ser.in.Read(buf)
+}
+
+func (ser seReader) Close() os.Error {
+	return nil
+}
+
+const mdcTrailerSize = 1 /* tag byte */ + 1 /* length byte */ + sha1.Size
+
+// An seMDCReader wraps an io.Reader, maintains a running hash and keeps hold
+// of the most recent 22 bytes (mdcTrailerSize). Upon EOF, those bytes form an
+// MDC packet containing a hash of the previous contents which is checked
+// against the running hash. See RFC 4880, section 5.13.
+type seMDCReader struct {
+	in          io.Reader
+	h           hash.Hash
+	trailer     [mdcTrailerSize]byte
+	scratch     [mdcTrailerSize]byte
+	trailerUsed int
+	error       bool
+	eof         bool
+}
+
+func (ser *seMDCReader) Read(buf []byte) (n int, err os.Error) {
+	if ser.error {
+		err = io.ErrUnexpectedEOF
+		return
+	}
+	if ser.eof {
+		err = os.EOF
+		return
+	}
+
+	// If we haven't yet filled the trailer buffer then we must do that
+	// first.
+	for ser.trailerUsed < mdcTrailerSize {
+		n, err = ser.in.Read(ser.trailer[ser.trailerUsed:])
+		ser.trailerUsed += n
+		if err == os.EOF {
+			if ser.trailerUsed != mdcTrailerSize {
+				n = 0
+				err = io.ErrUnexpectedEOF
+				ser.error = true
+				return
+			}
+			ser.eof = true
+			n = 0
+			return
+		}
+
+		if err != nil {
+			n = 0
+			return
+		}
+	}
+
+	// If it's a short read then we read into a temporary buffer and shift
+	// the data into the caller's buffer.
+	if len(buf) <= mdcTrailerSize {
+		n, err = readFull(ser.in, ser.scratch[:len(buf)])
+		copy(buf, ser.trailer[:n])
+		ser.h.Write(buf[:n])
+		copy(ser.trailer[:], ser.trailer[n:])
+		copy(ser.trailer[mdcTrailerSize-n:], ser.scratch[:])
+		if n < len(buf) {
+			ser.eof = true
+			err = os.EOF
+		}
+		return
+	}
+
+	n, err = ser.in.Read(buf[mdcTrailerSize:])
+	copy(buf, ser.trailer[:])
+	ser.h.Write(buf[:n])
+	copy(ser.trailer[:], buf[n:])
+
+	if err == os.EOF {
+		ser.eof = true
+	}
+	return
+}
+
+// This is a new-format packet tag byte for a type 19 (MDC) packet.
+const mdcPacketTagByte = byte(0x80) | 0x40 | 19
+
+func (ser *seMDCReader) Close() os.Error {
+	if ser.error {
+		return error.SignatureError("error during reading")
+	}
+
+	for !ser.eof {
+		// We haven't seen EOF so we need to read to the end
+		var buf [1024]byte
+		_, err := ser.Read(buf[:])
+		if err == os.EOF {
+			break
+		}
+		if err != nil {
+			return error.SignatureError("error during reading")
+		}
+	}
+
+	if ser.trailer[0] != mdcPacketTagByte || ser.trailer[1] != sha1.Size {
+		return error.SignatureError("MDC packet not found")
+	}
+	ser.h.Write(ser.trailer[:2])
+
+	final := ser.h.Sum()
+	if subtle.ConstantTimeCompare(final, ser.trailer[2:]) != 1 {
+		return error.SignatureError("hash mismatch")
+	}
+	return nil
+}
+
+// An seMDCWriter writes through to an io.WriteCloser while maintains a running
+// hash of the data written. On close, it emits an MDC packet containing the
+// running hash.
+type seMDCWriter struct {
+	w io.WriteCloser
+	h hash.Hash
+}
+
+func (w *seMDCWriter) Write(buf []byte) (n int, err os.Error) {
+	w.h.Write(buf)
+	return w.w.Write(buf)
+}
+
+func (w *seMDCWriter) Close() (err os.Error) {
+	var buf [mdcTrailerSize]byte
+
+	buf[0] = mdcPacketTagByte
+	buf[1] = sha1.Size
+	w.h.Write(buf[:2])
+	digest := w.h.Sum()
+	copy(buf[2:], digest)
+
+	_, err = w.w.Write(buf[:])
+	if err != nil {
+		return
+	}
+	return w.w.Close()
+}
+
+// noOpCloser is like an ioutil.NopCloser, but for an io.Writer.
+type noOpCloser struct {
+	w io.Writer
+}
+
+func (c noOpCloser) Write(data []byte) (n int, err os.Error) {
+	return c.w.Write(data)
+}
+
+func (c noOpCloser) Close() os.Error {
+	return nil
+}
+
+// SerializeSymmetricallyEncrypted serializes a symmetrically encrypted packet
+// to w and returns a WriteCloser to which the to-be-encrypted packets can be
+// written.
+func SerializeSymmetricallyEncrypted(w io.Writer, c CipherFunction, key []byte) (contents io.WriteCloser, err os.Error) {
+	if c.KeySize() != len(key) {
+		return nil, error.InvalidArgumentError("SymmetricallyEncrypted.Serialize: bad key length")
+	}
+	writeCloser := noOpCloser{w}
+	ciphertext, err := serializeStreamHeader(writeCloser, packetTypeSymmetricallyEncryptedMDC)
+	if err != nil {
+		return
+	}
+
+	_, err = ciphertext.Write([]byte{symmetricallyEncryptedVersion})
+	if err != nil {
+		return
+	}
+
+	block := c.new(key)
+	blockSize := block.BlockSize()
+	iv := make([]byte, blockSize)
+	_, err = rand.Reader.Read(iv)
+	if err != nil {
+		return
+	}
+	s, prefix := cipher.NewOCFBEncrypter(block, iv, cipher.OCFBNoResync)
+	_, err = ciphertext.Write(prefix)
+	if err != nil {
+		return
+	}
+	plaintext := cipher.StreamWriter{S: s, W: ciphertext}
+
+	h := sha1.New()
+	h.Write(iv)
+	h.Write(iv[blockSize-2:])
+	contents = &seMDCWriter{w: plaintext, h: h}
+	return
+}
diff --git a/src/pkg/crypto/openpgp/packet/symmetrically_encrypted_test.go b/src/pkg/crypto/openpgp/packet/symmetrically_encrypted_test.go
new file mode 100644
index 000000000..1054fc2f9
--- /dev/null
+++ b/src/pkg/crypto/openpgp/packet/symmetrically_encrypted_test.go
@@ -0,0 +1,124 @@
+// Copyright 2011 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package packet
+
+import (
+	"bytes"
+	"crypto/openpgp/error"
+	"crypto/sha1"
+	"encoding/hex"
+	"io"
+	"io/ioutil"
+	"os"
+	"testing"
+)
+
+// TestReader wraps a []byte and returns reads of a specific length.
+type testReader struct {
+	data   []byte
+	stride int
+}
+
+func (t *testReader) Read(buf []byte) (n int, err os.Error) {
+	n = t.stride
+	if n > len(t.data) {
+		n = len(t.data)
+	}
+	if n > len(buf) {
+		n = len(buf)
+	}
+	copy(buf, t.data)
+	t.data = t.data[n:]
+	if len(t.data) == 0 {
+		err = os.EOF
+	}
+	return
+}
+
+func testMDCReader(t *testing.T) {
+	mdcPlaintext, _ := hex.DecodeString(mdcPlaintextHex)
+
+	for stride := 1; stride < len(mdcPlaintext)/2; stride++ {
+		r := &testReader{data: mdcPlaintext, stride: stride}
+		mdcReader := &seMDCReader{in: r, h: sha1.New()}
+		body, err := ioutil.ReadAll(mdcReader)
+		if err != nil {
+			t.Errorf("stride: %d, error: %s", stride, err)
+			continue
+		}
+		if !bytes.Equal(body, mdcPlaintext[:len(mdcPlaintext)-22]) {
+			t.Errorf("stride: %d: bad contents %x", stride, body)
+			continue
+		}
+
+		err = mdcReader.Close()
+		if err != nil {
+			t.Errorf("stride: %d, error on Close: %s", stride, err)
+		}
+	}
+
+	mdcPlaintext[15] ^= 80
+
+	r := &testReader{data: mdcPlaintext, stride: 2}
+	mdcReader := &seMDCReader{in: r, h: sha1.New()}
+	_, err := ioutil.ReadAll(mdcReader)
+	if err != nil {
+		t.Errorf("corruption test, error: %s", err)
+		return
+	}
+	err = mdcReader.Close()
+	if err == nil {
+		t.Error("corruption: no error")
+	} else if _, ok := err.(*error.SignatureError); !ok {
+		t.Errorf("corruption: expected SignatureError, got: %s", err)
+	}
+}
+
+const mdcPlaintextHex = "a302789c3b2d93c4e0eb9aba22283539b3203335af44a134afb800c849cb4c4de10200aff40b45d31432c80cb384299a0655966d6939dfdeed1dddf980"
+
+func TestSerialize(t *testing.T) {
+	buf := bytes.NewBuffer(nil)
+	c := CipherAES128
+	key := make([]byte, c.KeySize())
+
+	w, err := SerializeSymmetricallyEncrypted(buf, c, key)
+	if err != nil {
+		t.Errorf("error from SerializeSymmetricallyEncrypted: %s", err)
+		return
+	}
+
+	contents := []byte("hello world\n")
+
+	w.Write(contents)
+	w.Close()
+
+	p, err := Read(buf)
+	if err != nil {
+		t.Errorf("error from Read: %s", err)
+		return
+	}
+
+	se, ok := p.(*SymmetricallyEncrypted)
+	if !ok {
+		t.Errorf("didn't read a *SymmetricallyEncrypted")
+		return
+	}
+
+	r, err := se.Decrypt(c, key)
+	if err != nil {
+		t.Errorf("error from Decrypt: %s", err)
+		return
+	}
+
+	contentsCopy := bytes.NewBuffer(nil)
+	_, err = io.Copy(contentsCopy, r)
+	if err != nil {
+		t.Errorf("error from io.Copy: %s", err)
+		return
+	}
+	if !bytes.Equal(contentsCopy.Bytes(), contents) {
+		t.Errorf("contents not equal got: %x want: %x", contentsCopy.Bytes(), contents)
+	}
+}
diff --git a/src/pkg/crypto/openpgp/packet/userid.go b/src/pkg/crypto/openpgp/packet/userid.go
new file mode 100644
index 000000000..0580ba3ed
--- /dev/null
+++ b/src/pkg/crypto/openpgp/packet/userid.go
@@ -0,0 +1,161 @@
+// Copyright 2011 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package packet
+
+import (
+	"io"
+	"io/ioutil"
+	"os"
+	"strings"
+)
+
+// UserId contains text that is intended to represent the name and email
+// address of the key holder. See RFC 4880, section 5.11. By convention, this
+// takes the form "Full Name (Comment) <email@example.com>"
+type UserId struct {
+	Id string // By convention, this takes the form "Full Name (Comment) <email@example.com>" which is split out in the fields below.
+
+	Name, Comment, Email string
+}
+
+func hasInvalidCharacters(s string) bool {
+	for _, c := range s {
+		switch c {
+		case '(', ')', '<', '>', 0:
+			return true
+		}
+	}
+	return false
+}
+
+// NewUserId returns a UserId or nil if any of the arguments contain invalid
+// characters. The invalid characters are '\x00', '(', ')', '<' and '>'
+func NewUserId(name, comment, email string) *UserId {
+	// RFC 4880 doesn't deal with the structure of userid strings; the
+	// name, comment and email form is just a convention. However, there's
+	// no convention about escaping the metacharacters and GPG just refuses
+	// to create user ids where, say, the name contains a '('. We mirror
+	// this behaviour.
+
+	if hasInvalidCharacters(name) || hasInvalidCharacters(comment) || hasInvalidCharacters(email) {
+		return nil
+	}
+
+	uid := new(UserId)
+	uid.Name, uid.Comment, uid.Email = name, comment, email
+	uid.Id = name
+	if len(comment) > 0 {
+		if len(uid.Id) > 0 {
+			uid.Id += " "
+		}
+		uid.Id += "("
+		uid.Id += comment
+		uid.Id += ")"
+	}
+	if len(email) > 0 {
+		if len(uid.Id) > 0 {
+			uid.Id += " "
+		}
+		uid.Id += "<"
+		uid.Id += email
+		uid.Id += ">"
+	}
+	return uid
+}
+
+func (uid *UserId) parse(r io.Reader) (err os.Error) {
+	// RFC 4880, section 5.11
+	b, err := ioutil.ReadAll(r)
+	if err != nil {
+		return
+	}
+	uid.Id = string(b)
+	uid.Name, uid.Comment, uid.Email = parseUserId(uid.Id)
+	return
+}
+
+// Serialize marshals uid to w in the form of an OpenPGP packet, including
+// header.
+func (uid *UserId) Serialize(w io.Writer) os.Error {
+	err := serializeHeader(w, packetTypeUserId, len(uid.Id))
+	if err != nil {
+		return err
+	}
+	_, err = w.Write([]byte(uid.Id))
+	return err
+}
+
+// parseUserId extracts the name, comment and email from a user id string that
+// is formatted as "Full Name (Comment) <email@example.com>".
+func parseUserId(id string) (name, comment, email string) {
+	var n, c, e struct {
+		start, end int
+	}
+	var state int
+
+	for offset, rune := range id {
+		switch state {
+		case 0:
+			// Entering name
+			n.start = offset
+			state = 1
+			fallthrough
+		case 1:
+			// In name
+			if rune == '(' {
+				state = 2
+				n.end = offset
+			} else if rune == '<' {
+				state = 5
+				n.end = offset
+			}
+		case 2:
+			// Entering comment
+			c.start = offset
+			state = 3
+			fallthrough
+		case 3:
+			// In comment
+			if rune == ')' {
+				state = 4
+				c.end = offset
+			}
+		case 4:
+			// Between comment and email
+			if rune == '<' {
+				state = 5
+			}
+		case 5:
+			// Entering email
+			e.start = offset
+			state = 6
+			fallthrough
+		case 6:
+			// In email
+			if rune == '>' {
+				state = 7
+				e.end = offset
+			}
+		default:
+			// After email
+		}
+	}
+	switch state {
+	case 1:
+		// ended in the name
+		n.end = len(id)
+	case 3:
+		// ended in comment
+		c.end = len(id)
+	case 6:
+		// ended in email
+		e.end = len(id)
+	}
+
+	name = strings.TrimSpace(id[n.start:n.end])
+	comment = strings.TrimSpace(id[c.start:c.end])
+	email = strings.TrimSpace(id[e.start:e.end])
+	return
+}
diff --git a/src/pkg/crypto/openpgp/packet/userid_test.go b/src/pkg/crypto/openpgp/packet/userid_test.go
new file mode 100644
index 000000000..296819389
--- /dev/null
+++ b/src/pkg/crypto/openpgp/packet/userid_test.go
@@ -0,0 +1,87 @@
+// Copyright 2011 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package packet
+
+import (
+	"testing"
+)
+
+var userIdTests = []struct {
+	id                   string
+	name, comment, email string
+}{
+	{"", "", "", ""},
+	{"John Smith", "John Smith", "", ""},
+	{"John Smith ()", "John Smith", "", ""},
+	{"John Smith () <>", "John Smith", "", ""},
+	{"(comment", "", "comment", ""},
+	{"(comment)", "", "comment", ""},
+	{"<email", "", "", "email"},
+	{"<email>   sdfk", "", "", "email"},
+	{"  John Smith  (  Comment ) asdkflj < email > lksdfj", "John Smith", "Comment", "email"},
+	{"  John Smith  < email > lksdfj", "John Smith", "", "email"},
+	{"(<foo", "", "<foo", ""},
+	{"René Descartes (العربي)", "René Descartes", "العربي", ""},
+}
+
+func TestParseUserId(t *testing.T) {
+	for i, test := range userIdTests {
+		name, comment, email := parseUserId(test.id)
+		if name != test.name {
+			t.Errorf("%d: name mismatch got:%s want:%s", i, name, test.name)
+		}
+		if comment != test.comment {
+			t.Errorf("%d: comment mismatch got:%s want:%s", i, comment, test.comment)
+		}
+		if email != test.email {
+			t.Errorf("%d: email mismatch got:%s want:%s", i, email, test.email)
+		}
+	}
+}
+
+var newUserIdTests = []struct {
+	name, comment, email, id string
+}{
+	{"foo", "", "", "foo"},
+	{"", "bar", "", "(bar)"},
+	{"", "", "baz", "<baz>"},
+	{"foo", "bar", "", "foo (bar)"},
+	{"foo", "", "baz", "foo <baz>"},
+	{"", "bar", "baz", "(bar) <baz>"},
+	{"foo", "bar", "baz", "foo (bar) <baz>"},
+}
+
+func TestNewUserId(t *testing.T) {
+	for i, test := range newUserIdTests {
+		uid := NewUserId(test.name, test.comment, test.email)
+		if uid == nil {
+			t.Errorf("#%d: returned nil", i)
+			continue
+		}
+		if uid.Id != test.id {
+			t.Errorf("#%d: got '%s', want '%s'", i, uid.Id, test.id)
+		}
+	}
+}
+
+var invalidNewUserIdTests = []struct {
+	name, comment, email string
+}{
+	{"foo(", "", ""},
+	{"foo<", "", ""},
+	{"", "bar)", ""},
+	{"", "bar<", ""},
+	{"", "", "baz>"},
+	{"", "", "baz)"},
+	{"", "", "baz\x00"},
+}
+
+func TestNewUserIdWithInvalidInput(t *testing.T) {
+	for i, test := range invalidNewUserIdTests {
+		if uid := NewUserId(test.name, test.comment, test.email); uid != nil {
+			t.Errorf("#%d: returned non-nil value: %#v", i, uid)
+		}
+	}
+}
diff --git a/src/pkg/crypto/openpgp/read.go b/src/pkg/crypto/openpgp/read.go
new file mode 100644
index 000000000..d95f613c6
--- /dev/null
+++ b/src/pkg/crypto/openpgp/read.go
@@ -0,0 +1,415 @@
+// Copyright 2011 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package openpgp implements high level operations on OpenPGP messages.
+package openpgp
+
+import (
+	"crypto"
+	"crypto/openpgp/armor"
+	"crypto/openpgp/error"
+	"crypto/openpgp/packet"
+	_ "crypto/sha256"
+	"hash"
+	"io"
+	"os"
+	"strconv"
+)
+
+// SignatureType is the armor type for a PGP signature.
+var SignatureType = "PGP SIGNATURE"
+
+// readArmored reads an armored block with the given type.
+func readArmored(r io.Reader, expectedType string) (body io.Reader, err os.Error) {
+	block, err := armor.Decode(r)
+	if err != nil {
+		return
+	}
+
+	if block.Type != expectedType {
+		return nil, error.InvalidArgumentError("expected '" + expectedType + "', got: " + block.Type)
+	}
+
+	return block.Body, nil
+}
+
+// MessageDetails contains the result of parsing an OpenPGP encrypted and/or
+// signed message.
+type MessageDetails struct {
+	IsEncrypted              bool                // true if the message was encrypted.
+	EncryptedToKeyIds        []uint64            // the list of recipient key ids.
+	IsSymmetricallyEncrypted bool                // true if a passphrase could have decrypted the message.
+	DecryptedWith            Key                 // the private key used to decrypt the message, if any.
+	IsSigned                 bool                // true if the message is signed.
+	SignedByKeyId            uint64              // the key id of the signer, if any.
+	SignedBy                 *Key                // the key of the signer, if available.
+	LiteralData              *packet.LiteralData // the metadata of the contents
+	UnverifiedBody           io.Reader           // the contents of the message.
+
+	// If IsSigned is true and SignedBy is non-zero then the signature will
+	// be verified as UnverifiedBody is read. The signature cannot be
+	// checked until the whole of UnverifiedBody is read so UnverifiedBody
+	// must be consumed until EOF before the data can trusted. Even if a
+	// message isn't signed (or the signer is unknown) the data may contain
+	// an authentication code that is only checked once UnverifiedBody has
+	// been consumed. Once EOF has been seen, the following fields are
+	// valid. (An authentication code failure is reported as a
+	// SignatureError error when reading from UnverifiedBody.)
+	SignatureError os.Error          // nil if the signature is good.
+	Signature      *packet.Signature // the signature packet itself.
+
+	decrypted io.ReadCloser
+}
+
+// A PromptFunction is used as a callback by functions that may need to decrypt
+// a private key, or prompt for a passphrase. It is called with a list of
+// acceptable, encrypted private keys and a boolean that indicates whether a
+// passphrase is usable. It should either decrypt a private key or return a
+// passphrase to try. If the decrypted private key or given passphrase isn't
+// correct, the function will be called again, forever. Any error returned will
+// be passed up.
+type PromptFunction func(keys []Key, symmetric bool) ([]byte, os.Error)
+
+// A keyEnvelopePair is used to store a private key with the envelope that
+// contains a symmetric key, encrypted with that key.
+type keyEnvelopePair struct {
+	key          Key
+	encryptedKey *packet.EncryptedKey
+}
+
+// ReadMessage parses an OpenPGP message that may be signed and/or encrypted.
+// The given KeyRing should contain both public keys (for signature
+// verification) and, possibly encrypted, private keys for decrypting.
+func ReadMessage(r io.Reader, keyring KeyRing, prompt PromptFunction) (md *MessageDetails, err os.Error) {
+	var p packet.Packet
+
+	var symKeys []*packet.SymmetricKeyEncrypted
+	var pubKeys []keyEnvelopePair
+	var se *packet.SymmetricallyEncrypted
+
+	packets := packet.NewReader(r)
+	md = new(MessageDetails)
+	md.IsEncrypted = true
+
+	// The message, if encrypted, starts with a number of packets
+	// containing an encrypted decryption key. The decryption key is either
+	// encrypted to a public key, or with a passphrase. This loop
+	// collects these packets.
+ParsePackets:
+	for {
+		p, err = packets.Next()
+		if err != nil {
+			return nil, err
+		}
+		switch p := p.(type) {
+		case *packet.SymmetricKeyEncrypted:
+			// This packet contains the decryption key encrypted with a passphrase.
+			md.IsSymmetricallyEncrypted = true
+			symKeys = append(symKeys, p)
+		case *packet.EncryptedKey:
+			// This packet contains the decryption key encrypted to a public key.
+			md.EncryptedToKeyIds = append(md.EncryptedToKeyIds, p.KeyId)
+			switch p.Algo {
+			case packet.PubKeyAlgoRSA, packet.PubKeyAlgoRSAEncryptOnly, packet.PubKeyAlgoElGamal:
+				break
+			default:
+				continue
+			}
+			var keys []Key
+			if p.KeyId == 0 {
+				keys = keyring.DecryptionKeys()
+			} else {
+				keys = keyring.KeysById(p.KeyId)
+			}
+			for _, k := range keys {
+				pubKeys = append(pubKeys, keyEnvelopePair{k, p})
+			}
+		case *packet.SymmetricallyEncrypted:
+			se = p
+			break ParsePackets
+		case *packet.Compressed, *packet.LiteralData, *packet.OnePassSignature:
+			// This message isn't encrypted.
+			if len(symKeys) != 0 || len(pubKeys) != 0 {
+				return nil, error.StructuralError("key material not followed by encrypted message")
+			}
+			packets.Unread(p)
+			return readSignedMessage(packets, nil, keyring)
+		}
+	}
+
+	var candidates []Key
+	var decrypted io.ReadCloser
+
+	// Now that we have the list of encrypted keys we need to decrypt at
+	// least one of them or, if we cannot, we need to call the prompt
+	// function so that it can decrypt a key or give us a passphrase.
+FindKey:
+	for {
+		// See if any of the keys already have a private key available
+		candidates = candidates[:0]
+		candidateFingerprints := make(map[string]bool)
+
+		for _, pk := range pubKeys {
+			if pk.key.PrivateKey == nil {
+				continue
+			}
+			if !pk.key.PrivateKey.Encrypted {
+				if len(pk.encryptedKey.Key) == 0 {
+					pk.encryptedKey.Decrypt(pk.key.PrivateKey)
+				}
+				if len(pk.encryptedKey.Key) == 0 {
+					continue
+				}
+				decrypted, err = se.Decrypt(pk.encryptedKey.CipherFunc, pk.encryptedKey.Key)
+				if err != nil && err != error.KeyIncorrectError {
+					return nil, err
+				}
+				if decrypted != nil {
+					md.DecryptedWith = pk.key
+					break FindKey
+				}
+			} else {
+				fpr := string(pk.key.PublicKey.Fingerprint[:])
+				if v := candidateFingerprints[fpr]; v {
+					continue
+				}
+				candidates = append(candidates, pk.key)
+				candidateFingerprints[fpr] = true
+			}
+		}
+
+		if len(candidates) == 0 && len(symKeys) == 0 {
+			return nil, error.KeyIncorrectError
+		}
+
+		if prompt == nil {
+			return nil, error.KeyIncorrectError
+		}
+
+		passphrase, err := prompt(candidates, len(symKeys) != 0)
+		if err != nil {
+			return nil, err
+		}
+
+		// Try the symmetric passphrase first
+		if len(symKeys) != 0 && passphrase != nil {
+			for _, s := range symKeys {
+				err = s.Decrypt(passphrase)
+				if err == nil && !s.Encrypted {
+					decrypted, err = se.Decrypt(s.CipherFunc, s.Key)
+					if err != nil && err != error.KeyIncorrectError {
+						return nil, err
+					}
+					if decrypted != nil {
+						break FindKey
+					}
+				}
+
+			}
+		}
+	}
+
+	md.decrypted = decrypted
+	packets.Push(decrypted)
+	return readSignedMessage(packets, md, keyring)
+}
+
+// readSignedMessage reads a possibly signed message if mdin is non-zero then
+// that structure is updated and returned. Otherwise a fresh MessageDetails is
+// used.
+func readSignedMessage(packets *packet.Reader, mdin *MessageDetails, keyring KeyRing) (md *MessageDetails, err os.Error) {
+	if mdin == nil {
+		mdin = new(MessageDetails)
+	}
+	md = mdin
+
+	var p packet.Packet
+	var h hash.Hash
+	var wrappedHash hash.Hash
+FindLiteralData:
+	for {
+		p, err = packets.Next()
+		if err != nil {
+			return nil, err
+		}
+		switch p := p.(type) {
+		case *packet.Compressed:
+			packets.Push(p.Body)
+		case *packet.OnePassSignature:
+			if !p.IsLast {
+				return nil, error.UnsupportedError("nested signatures")
+			}
+
+			h, wrappedHash, err = hashForSignature(p.Hash, p.SigType)
+			if err != nil {
+				md = nil
+				return
+			}
+
+			md.IsSigned = true
+			md.SignedByKeyId = p.KeyId
+			keys := keyring.KeysById(p.KeyId)
+			for i, key := range keys {
+				if key.SelfSignature.FlagsValid && !key.SelfSignature.FlagSign {
+					continue
+				}
+				md.SignedBy = &keys[i]
+				break
+			}
+		case *packet.LiteralData:
+			md.LiteralData = p
+			break FindLiteralData
+		}
+	}
+
+	if md.SignedBy != nil {
+		md.UnverifiedBody = &signatureCheckReader{packets, h, wrappedHash, md}
+	} else if md.decrypted != nil {
+		md.UnverifiedBody = checkReader{md}
+	} else {
+		md.UnverifiedBody = md.LiteralData.Body
+	}
+
+	return md, nil
+}
+
+// hashForSignature returns a pair of hashes that can be used to verify a
+// signature. The signature may specify that the contents of the signed message
+// should be preprocessed (i.e. to normalize line endings). Thus this function
+// returns two hashes. The second should be used to hash the message itself and
+// performs any needed preprocessing.
+func hashForSignature(hashId crypto.Hash, sigType packet.SignatureType) (hash.Hash, hash.Hash, os.Error) {
+	h := hashId.New()
+	if h == nil {
+		return nil, nil, error.UnsupportedError("hash not available: " + strconv.Itoa(int(hashId)))
+	}
+
+	switch sigType {
+	case packet.SigTypeBinary:
+		return h, h, nil
+	case packet.SigTypeText:
+		return h, NewCanonicalTextHash(h), nil
+	}
+
+	return nil, nil, error.UnsupportedError("unsupported signature type: " + strconv.Itoa(int(sigType)))
+}
+
+// checkReader wraps an io.Reader from a LiteralData packet. When it sees EOF
+// it closes the ReadCloser from any SymmetricallyEncrypted packet to trigger
+// MDC checks.
+type checkReader struct {
+	md *MessageDetails
+}
+
+func (cr checkReader) Read(buf []byte) (n int, err os.Error) {
+	n, err = cr.md.LiteralData.Body.Read(buf)
+	if err == os.EOF {
+		mdcErr := cr.md.decrypted.Close()
+		if mdcErr != nil {
+			err = mdcErr
+		}
+	}
+	return
+}
+
+// signatureCheckReader wraps an io.Reader from a LiteralData packet and hashes
+// the data as it is read. When it sees an EOF from the underlying io.Reader
+// it parses and checks a trailing Signature packet and triggers any MDC checks.
+type signatureCheckReader struct {
+	packets        *packet.Reader
+	h, wrappedHash hash.Hash
+	md             *MessageDetails
+}
+
+func (scr *signatureCheckReader) Read(buf []byte) (n int, err os.Error) {
+	n, err = scr.md.LiteralData.Body.Read(buf)
+	scr.wrappedHash.Write(buf[:n])
+	if err == os.EOF {
+		var p packet.Packet
+		p, scr.md.SignatureError = scr.packets.Next()
+		if scr.md.SignatureError != nil {
+			return
+		}
+
+		var ok bool
+		if scr.md.Signature, ok = p.(*packet.Signature); !ok {
+			scr.md.SignatureError = error.StructuralError("LiteralData not followed by Signature")
+			return
+		}
+
+		scr.md.SignatureError = scr.md.SignedBy.PublicKey.VerifySignature(scr.h, scr.md.Signature)
+
+		// The SymmetricallyEncrypted packet, if any, might have an
+		// unsigned hash of its own. In order to check this we need to
+		// close that Reader.
+		if scr.md.decrypted != nil {
+			mdcErr := scr.md.decrypted.Close()
+			if mdcErr != nil {
+				err = mdcErr
+			}
+		}
+	}
+	return
+}
+
+// CheckDetachedSignature takes a signed file and a detached signature and
+// returns the signer if the signature is valid. If the signer isn't know,
+// UnknownIssuerError is returned.
+func CheckDetachedSignature(keyring KeyRing, signed, signature io.Reader) (signer *Entity, err os.Error) {
+	p, err := packet.Read(signature)
+	if err != nil {
+		return
+	}
+
+	sig, ok := p.(*packet.Signature)
+	if !ok {
+		return nil, error.StructuralError("non signature packet found")
+	}
+
+	if sig.IssuerKeyId == nil {
+		return nil, error.StructuralError("signature doesn't have an issuer")
+	}
+
+	keys := keyring.KeysById(*sig.IssuerKeyId)
+	if len(keys) == 0 {
+		return nil, error.UnknownIssuerError
+	}
+
+	h, wrappedHash, err := hashForSignature(sig.Hash, sig.SigType)
+	if err != nil {
+		return
+	}
+
+	_, err = io.Copy(wrappedHash, signed)
+	if err != nil && err != os.EOF {
+		return
+	}
+
+	for _, key := range keys {
+		if key.SelfSignature.FlagsValid && !key.SelfSignature.FlagSign {
+			continue
+		}
+		err = key.PublicKey.VerifySignature(h, sig)
+		if err == nil {
+			return key.Entity, nil
+		}
+	}
+
+	if err != nil {
+		return
+	}
+
+	return nil, error.UnknownIssuerError
+}
+
+// CheckArmoredDetachedSignature performs the same actions as
+// CheckDetachedSignature but expects the signature to be armored.
+func CheckArmoredDetachedSignature(keyring KeyRing, signed, signature io.Reader) (signer *Entity, err os.Error) {
+	body, err := readArmored(signature, SignatureType)
+	if err != nil {
+		return
+	}
+
+	return CheckDetachedSignature(keyring, signed, body)
+}
diff --git a/src/pkg/crypto/openpgp/read_test.go b/src/pkg/crypto/openpgp/read_test.go
new file mode 100644
index 000000000..4dc290ef2
--- /dev/null
+++ b/src/pkg/crypto/openpgp/read_test.go
@@ -0,0 +1,361 @@
+// Copyright 2011 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package openpgp
+
+import (
+	"bytes"
+	"crypto/openpgp/error"
+	"encoding/hex"
+	"io"
+	"io/ioutil"
+	"os"
+	"testing"
+)
+
+func readerFromHex(s string) io.Reader {
+	data, err := hex.DecodeString(s)
+	if err != nil {
+		panic("readerFromHex: bad input")
+	}
+	return bytes.NewBuffer(data)
+}
+
+func TestReadKeyRing(t *testing.T) {
+	kring, err := ReadKeyRing(readerFromHex(testKeys1And2Hex))
+	if err != nil {
+		t.Error(err)
+		return
+	}
+	if len(kring) != 2 || uint32(kring[0].PrimaryKey.KeyId) != 0xC20C31BB || uint32(kring[1].PrimaryKey.KeyId) != 0x1E35246B {
+		t.Errorf("bad keyring: %#v", kring)
+	}
+}
+
+func TestRereadKeyRing(t *testing.T) {
+	kring, err := ReadKeyRing(readerFromHex(testKeys1And2Hex))
+	if err != nil {
+		t.Errorf("error in initial parse: %s", err)
+		return
+	}
+	out := new(bytes.Buffer)
+	err = kring[0].Serialize(out)
+	if err != nil {
+		t.Errorf("error in serialization: %s", err)
+		return
+	}
+	kring, err = ReadKeyRing(out)
+	if err != nil {
+		t.Errorf("error in second parse: %s", err)
+		return
+	}
+
+	if len(kring) != 1 || uint32(kring[0].PrimaryKey.KeyId) != 0xC20C31BB {
+		t.Errorf("bad keyring: %#v", kring)
+	}
+}
+
+func TestReadPrivateKeyRing(t *testing.T) {
+	kring, err := ReadKeyRing(readerFromHex(testKeys1And2PrivateHex))
+	if err != nil {
+		t.Error(err)
+		return
+	}
+	if len(kring) != 2 || uint32(kring[0].PrimaryKey.KeyId) != 0xC20C31BB || uint32(kring[1].PrimaryKey.KeyId) != 0x1E35246B || kring[0].PrimaryKey == nil {
+		t.Errorf("bad keyring: %#v", kring)
+	}
+}
+
+func TestReadDSAKey(t *testing.T) {
+	kring, err := ReadKeyRing(readerFromHex(dsaTestKeyHex))
+	if err != nil {
+		t.Error(err)
+		return
+	}
+	if len(kring) != 1 || uint32(kring[0].PrimaryKey.KeyId) != 0x0CCC0360 {
+		t.Errorf("bad parse: %#v", kring)
+	}
+}
+
+func TestGetKeyById(t *testing.T) {
+	kring, _ := ReadKeyRing(readerFromHex(testKeys1And2Hex))
+
+	keys := kring.KeysById(0xa34d7e18c20c31bb)
+	if len(keys) != 1 || keys[0].Entity != kring[0] {
+		t.Errorf("bad result for 0xa34d7e18c20c31bb: %#v", keys)
+	}
+
+	keys = kring.KeysById(0xfd94408d4543314f)
+	if len(keys) != 1 || keys[0].Entity != kring[0] {
+		t.Errorf("bad result for 0xa34d7e18c20c31bb: %#v", keys)
+	}
+}
+
+func checkSignedMessage(t *testing.T, signedHex, expected string) {
+	kring, _ := ReadKeyRing(readerFromHex(testKeys1And2Hex))
+
+	md, err := ReadMessage(readerFromHex(signedHex), kring, nil)
+	if err != nil {
+		t.Error(err)
+		return
+	}
+
+	if !md.IsSigned || md.SignedByKeyId != 0xa34d7e18c20c31bb || md.SignedBy == nil || md.IsEncrypted || md.IsSymmetricallyEncrypted || len(md.EncryptedToKeyIds) != 0 || md.IsSymmetricallyEncrypted {
+		t.Errorf("bad MessageDetails: %#v", md)
+	}
+
+	contents, err := ioutil.ReadAll(md.UnverifiedBody)
+	if err != nil {
+		t.Errorf("error reading UnverifiedBody: %s", err)
+	}
+	if string(contents) != expected {
+		t.Errorf("bad UnverifiedBody got:%s want:%s", string(contents), expected)
+	}
+	if md.SignatureError != nil || md.Signature == nil {
+		t.Errorf("failed to validate: %s", md.SignatureError)
+	}
+}
+
+func TestSignedMessage(t *testing.T) {
+	checkSignedMessage(t, signedMessageHex, signedInput)
+}
+
+func TestTextSignedMessage(t *testing.T) {
+	checkSignedMessage(t, signedTextMessageHex, signedTextInput)
+}
+
+var signedEncryptedMessageTests = []struct {
+	keyRingHex       string
+	messageHex       string
+	signedByKeyId    uint64
+	encryptedToKeyId uint64
+}{
+	{
+		testKeys1And2PrivateHex,
+		signedEncryptedMessageHex,
+		0xa34d7e18c20c31bb,
+		0x2a67d68660df41c7,
+	},
+	{
+		dsaElGamalTestKeysHex,
+		signedEncryptedMessage2Hex,
+		0x33af447ccd759b09,
+		0xcf6a7abcd43e3673,
+	},
+}
+
+func TestSignedEncryptedMessage(t *testing.T) {
+	for i, test := range signedEncryptedMessageTests {
+		expected := "Signed and encrypted message\n"
+		kring, _ := ReadKeyRing(readerFromHex(test.keyRingHex))
+		prompt := func(keys []Key, symmetric bool) ([]byte, os.Error) {
+			if symmetric {
+				t.Errorf("prompt: message was marked as symmetrically encrypted")
+				return nil, error.KeyIncorrectError
+			}
+
+			if len(keys) == 0 {
+				t.Error("prompt: no keys requested")
+				return nil, error.KeyIncorrectError
+			}
+
+			err := keys[0].PrivateKey.Decrypt([]byte("passphrase"))
+			if err != nil {
+				t.Errorf("prompt: error decrypting key: %s", err)
+				return nil, error.KeyIncorrectError
+			}
+
+			return nil, nil
+		}
+
+		md, err := ReadMessage(readerFromHex(test.messageHex), kring, prompt)
+		if err != nil {
+			t.Errorf("#%d: error reading message: %s", i, err)
+			return
+		}
+
+		if !md.IsSigned || md.SignedByKeyId != test.signedByKeyId || md.SignedBy == nil || !md.IsEncrypted || md.IsSymmetricallyEncrypted || len(md.EncryptedToKeyIds) == 0 || md.EncryptedToKeyIds[0] != test.encryptedToKeyId {
+			t.Errorf("#%d: bad MessageDetails: %#v", i, md)
+		}
+
+		contents, err := ioutil.ReadAll(md.UnverifiedBody)
+		if err != nil {
+			t.Errorf("#%d: error reading UnverifiedBody: %s", i, err)
+		}
+		if string(contents) != expected {
+			t.Errorf("#%d: bad UnverifiedBody got:%s want:%s", i, string(contents), expected)
+		}
+
+		if md.SignatureError != nil || md.Signature == nil {
+			t.Errorf("#%d: failed to validate: %s", i, md.SignatureError)
+		}
+	}
+}
+
+func TestUnspecifiedRecipient(t *testing.T) {
+	expected := "Recipient unspecified\n"
+	kring, _ := ReadKeyRing(readerFromHex(testKeys1And2PrivateHex))
+
+	md, err := ReadMessage(readerFromHex(recipientUnspecifiedHex), kring, nil)
+	if err != nil {
+		t.Errorf("error reading message: %s", err)
+		return
+	}
+
+	contents, err := ioutil.ReadAll(md.UnverifiedBody)
+	if err != nil {
+		t.Errorf("error reading UnverifiedBody: %s", err)
+	}
+	if string(contents) != expected {
+		t.Errorf("bad UnverifiedBody got:%s want:%s", string(contents), expected)
+	}
+}
+
+func TestSymmetricallyEncrypted(t *testing.T) {
+	expected := "Symmetrically encrypted.\n"
+
+	prompt := func(keys []Key, symmetric bool) ([]byte, os.Error) {
+		if len(keys) != 0 {
+			t.Errorf("prompt: len(keys) = %d (want 0)", len(keys))
+		}
+
+		if !symmetric {
+			t.Errorf("symmetric is not set")
+		}
+
+		return []byte("password"), nil
+	}
+
+	md, err := ReadMessage(readerFromHex(symmetricallyEncryptedCompressedHex), nil, prompt)
+	if err != nil {
+		t.Errorf("ReadMessage: %s", err)
+		return
+	}
+
+	contents, err := ioutil.ReadAll(md.UnverifiedBody)
+	if err != nil {
+		t.Errorf("ReadAll: %s", err)
+	}
+
+	expectedCreationTime := uint32(1295992998)
+	if md.LiteralData.Time != expectedCreationTime {
+		t.Errorf("LiteralData.Time is %d, want %d", md.LiteralData.Time, expectedCreationTime)
+	}
+
+	if string(contents) != expected {
+		t.Errorf("contents got: %s want: %s", string(contents), expected)
+	}
+}
+
+func testDetachedSignature(t *testing.T, kring KeyRing, signature io.Reader, sigInput, tag string, expectedSignerKeyId uint64) {
+	signed := bytes.NewBufferString(sigInput)
+	signer, err := CheckDetachedSignature(kring, signed, signature)
+	if err != nil {
+		t.Errorf("%s: signature error: %s", tag, err)
+		return
+	}
+	if signer == nil {
+		t.Errorf("%s: signer is nil", tag)
+		return
+	}
+	if signer.PrimaryKey.KeyId != expectedSignerKeyId {
+		t.Errorf("%s: wrong signer got:%x want:%x", tag, signer.PrimaryKey.KeyId, expectedSignerKeyId)
+	}
+}
+
+func TestDetachedSignature(t *testing.T) {
+	kring, _ := ReadKeyRing(readerFromHex(testKeys1And2Hex))
+	testDetachedSignature(t, kring, readerFromHex(detachedSignatureHex), signedInput, "binary", testKey1KeyId)
+	testDetachedSignature(t, kring, readerFromHex(detachedSignatureTextHex), signedInput, "text", testKey1KeyId)
+}
+
+func TestDetachedSignatureDSA(t *testing.T) {
+	kring, _ := ReadKeyRing(readerFromHex(dsaTestKeyHex))
+	testDetachedSignature(t, kring, readerFromHex(detachedSignatureDSAHex), signedInput, "binary", testKey3KeyId)
+}
+
+func TestReadingArmoredPrivateKey(t *testing.T) {
+	el, err := ReadArmoredKeyRing(bytes.NewBufferString(armoredPrivateKeyBlock))
+	if err != nil {
+		t.Error(err)
+	}
+	if len(el) != 1 {
+		t.Errorf("got %d entities, wanted 1\n", len(el))
+	}
+}
+
+func TestNoArmoredData(t *testing.T) {
+	_, err := ReadArmoredKeyRing(bytes.NewBufferString("foo"))
+	if _, ok := err.(error.InvalidArgumentError); !ok {
+		t.Errorf("error was not an InvalidArgumentError: %s", err)
+	}
+}
+
+const testKey1KeyId = 0xA34D7E18C20C31BB
+const testKey3KeyId = 0x338934250CCC0360
+
+const signedInput = "Signed message\nline 2\nline 3\n"
+const signedTextInput = "Signed message\r\nline 2\r\nline 3\r\n"
+
+const recipientUnspecifiedHex = "848c0300000000000000000103ff62d4d578d03cf40c3da998dfe216c074fa6ddec5e31c197c9666ba292830d91d18716a80f699f9d897389a90e6d62d0238f5f07a5248073c0f24920e4bc4a30c2d17ee4e0cae7c3d4aaa4e8dced50e3010a80ee692175fa0385f62ecca4b56ee6e9980aa3ec51b61b077096ac9e800edaf161268593eedb6cc7027ff5cb32745d250010d407a6221ae22ef18469b444f2822478c4d190b24d36371a95cb40087cdd42d9399c3d06a53c0673349bfb607927f20d1e122bde1e2bf3aa6cae6edf489629bcaa0689539ae3b718914d88ededc3b"
+
+const detachedSignatureHex = "889c04000102000605024d449cd1000a0910a34d7e18c20c31bb167603ff57718d09f28a519fdc7b5a68b6a3336da04df85e38c5cd5d5bd2092fa4629848a33d85b1729402a2aab39c3ac19f9d573f773cc62c264dc924c067a79dfd8a863ae06c7c8686120760749f5fd9b1e03a64d20a7df3446ddc8f0aeadeaeba7cbaee5c1e366d65b6a0c6cc749bcb912d2f15013f812795c2e29eb7f7b77f39ce77"
+
+const detachedSignatureTextHex = "889c04010102000605024d449d21000a0910a34d7e18c20c31bbc8c60400a24fbef7342603a41cb1165767bd18985d015fb72fe05db42db36cfb2f1d455967f1e491194fbf6cf88146222b23bf6ffbd50d17598d976a0417d3192ff9cc0034fd00f287b02e90418bbefe609484b09231e4e7a5f3562e199bf39909ab5276c4d37382fe088f6b5c3426fc1052865da8b3ab158672d58b6264b10823dc4b39"
+
+const detachedSignatureDSAHex = "884604001102000605024d6c4eac000a0910338934250ccc0360f18d00a087d743d6405ed7b87755476629600b8b694a39e900a0abff8126f46faf1547c1743c37b21b4ea15b8f83"
+
+const testKeys1And2Hex = "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"
+
+const testKeys1And2PrivateHex = "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"
+
+const dsaElGamalTestKeysHex = "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"
+
+const signedMessageHex = "a3019bc0cbccc0c4b8d8b74ee2108fe16ec6d3ca490cbe362d3f8333d3f352531472538b8b13d353b97232f352158c20943157c71c16064626063656269052062e4e01987e9b6fccff4b7df3a34c534b23e679cbec3bc0f8f6e64dfb4b55fe3f8efa9ce110ddb5cd79faf1d753c51aecfa669f7e7aa043436596cccc3359cb7dd6bbe9ecaa69e5989d9e57209571edc0b2fa7f57b9b79a64ee6e99ce1371395fee92fec2796f7b15a77c386ff668ee27f6d38f0baa6c438b561657377bf6acff3c5947befd7bf4c196252f1d6e5c524d0300"
+
+const signedTextMessageHex = "a3019bc0cbccc8c4b8d8b74ee2108fe16ec6d36a250cbece0c178233d3f352531472538b8b13d35379b97232f352158ca0b4312f57c71c1646462606365626906a062e4e019811591798ff99bf8afee860b0d8a8c2a85c3387e3bcf0bb3b17987f2bbcfab2aa526d930cbfd3d98757184df3995c9f3e7790e36e3e9779f06089d4c64e9e47dd6202cb6e9bc73c5d11bb59fbaf89d22d8dc7cf199ddf17af96e77c5f65f9bbed56f427bd8db7af37f6c9984bf9385efaf5f184f986fb3e6adb0ecfe35bbf92d16a7aa2a344fb0bc52fb7624f0200"
+
+const signedEncryptedMessageHex = "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"
+
+const signedEncryptedMessage2Hex = "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"
+
+const symmetricallyEncryptedCompressedHex = "8c0d04030302eb4a03808145d0d260c92f714339e13de5a79881216431925bf67ee2898ea61815f07894cd0703c50d0a76ef64d482196f47a8bc729af9b80bb6"
+
+const dsaTestKeyHex = "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"
+
+const dsaTestKeyPrivateHex = "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"
+
+const armoredPrivateKeyBlock = `-----BEGIN PGP PRIVATE KEY BLOCK-----
+Version: GnuPG v1.4.10 (GNU/Linux)
+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+=zNCn
+-----END PGP PRIVATE KEY BLOCK-----`
diff --git a/src/pkg/crypto/openpgp/s2k/Makefile b/src/pkg/crypto/openpgp/s2k/Makefile
new file mode 100644
index 000000000..731d53431
--- /dev/null
+++ b/src/pkg/crypto/openpgp/s2k/Makefile
@@ -0,0 +1,11 @@
+# Copyright 2011 The Go Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style
+# license that can be found in the LICENSE file.
+
+include ../../../../Make.inc
+
+TARG=crypto/openpgp/s2k
+GOFILES=\
+	s2k.go\
+
+include ../../../../Make.pkg
diff --git a/src/pkg/crypto/openpgp/s2k/s2k.go b/src/pkg/crypto/openpgp/s2k/s2k.go
new file mode 100644
index 000000000..da926a76e
--- /dev/null
+++ b/src/pkg/crypto/openpgp/s2k/s2k.go
@@ -0,0 +1,180 @@
+// Copyright 2011 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package s2k implements the various OpenPGP string-to-key transforms as
+// specified in RFC 4800 section 3.7.1.
+package s2k
+
+import (
+	"crypto"
+	"crypto/openpgp/error"
+	"hash"
+	"io"
+	"os"
+	"strconv"
+)
+
+// Simple writes to out the result of computing the Simple S2K function (RFC
+// 4880, section 3.7.1.1) using the given hash and input passphrase.
+func Simple(out []byte, h hash.Hash, in []byte) {
+	Salted(out, h, in, nil)
+}
+
+var zero [1]byte
+
+// Salted writes to out the result of computing the Salted S2K function (RFC
+// 4880, section 3.7.1.2) using the given hash, input passphrase and salt.
+func Salted(out []byte, h hash.Hash, in []byte, salt []byte) {
+	done := 0
+
+	for i := 0; done < len(out); i++ {
+		h.Reset()
+		for j := 0; j < i; j++ {
+			h.Write(zero[:])
+		}
+		h.Write(salt)
+		h.Write(in)
+		n := copy(out[done:], h.Sum())
+		done += n
+	}
+}
+
+// Iterated writes to out the result of computing the Iterated and Salted S2K
+// function (RFC 4880, section 3.7.1.3) using the given hash, input passphrase,
+// salt and iteration count.
+func Iterated(out []byte, h hash.Hash, in []byte, salt []byte, count int) {
+	combined := make([]byte, len(in)+len(salt))
+	copy(combined, salt)
+	copy(combined[len(salt):], in)
+
+	if count < len(combined) {
+		count = len(combined)
+	}
+
+	done := 0
+	for i := 0; done < len(out); i++ {
+		h.Reset()
+		for j := 0; j < i; j++ {
+			h.Write(zero[:])
+		}
+		written := 0
+		for written < count {
+			if written+len(combined) > count {
+				todo := count - written
+				h.Write(combined[:todo])
+				written = count
+			} else {
+				h.Write(combined)
+				written += len(combined)
+			}
+		}
+		n := copy(out[done:], h.Sum())
+		done += n
+	}
+}
+
+// Parse reads a binary specification for a string-to-key transformation from r
+// and returns a function which performs that transform.
+func Parse(r io.Reader) (f func(out, in []byte), err os.Error) {
+	var buf [9]byte
+
+	_, err = io.ReadFull(r, buf[:2])
+	if err != nil {
+		return
+	}
+
+	hash, ok := HashIdToHash(buf[1])
+	if !ok {
+		return nil, error.UnsupportedError("hash for S2K function: " + strconv.Itoa(int(buf[1])))
+	}
+	h := hash.New()
+	if h == nil {
+		return nil, error.UnsupportedError("hash not available: " + strconv.Itoa(int(hash)))
+	}
+
+	switch buf[0] {
+	case 1:
+		f := func(out, in []byte) {
+			Simple(out, h, in)
+		}
+		return f, nil
+	case 2:
+		_, err := io.ReadFull(r, buf[:8])
+		if err != nil {
+			return
+		}
+		f := func(out, in []byte) {
+			Salted(out, h, in, buf[:8])
+		}
+		return f, nil
+	case 3:
+		_, err := io.ReadFull(r, buf[:9])
+		if err != nil {
+			return
+		}
+		count := (16 + int(buf[8]&15)) << (uint32(buf[8]>>4) + 6)
+		f := func(out, in []byte) {
+			Iterated(out, h, in, buf[:8], count)
+		}
+		return f, nil
+	}
+
+	return nil, error.UnsupportedError("S2K function")
+}
+
+// Serialize salts and stretches the given passphrase and writes the resulting
+// key into key. It also serializes an S2K descriptor to w.
+func Serialize(w io.Writer, key []byte, rand io.Reader, passphrase []byte) os.Error {
+	var buf [11]byte
+	buf[0] = 3 /* iterated and salted */
+	buf[1], _ = HashToHashId(crypto.SHA1)
+	salt := buf[2:10]
+	if _, err := io.ReadFull(rand, salt); err != nil {
+		return err
+	}
+	const count = 65536 // this is the default in gpg
+	buf[10] = 96        // 65536 iterations
+	if _, err := w.Write(buf[:]); err != nil {
+		return err
+	}
+
+	Iterated(key, crypto.SHA1.New(), passphrase, salt, count)
+	return nil
+}
+
+// hashToHashIdMapping contains pairs relating OpenPGP's hash identifier with
+// Go's crypto.Hash type. See RFC 4880, section 9.4.
+var hashToHashIdMapping = []struct {
+	id   byte
+	hash crypto.Hash
+}{
+	{1, crypto.MD5},
+	{2, crypto.SHA1},
+	{3, crypto.RIPEMD160},
+	{8, crypto.SHA256},
+	{9, crypto.SHA384},
+	{10, crypto.SHA512},
+	{11, crypto.SHA224},
+}
+
+// HashIdToHash returns a crypto.Hash which corresponds to the given OpenPGP
+// hash id.
+func HashIdToHash(id byte) (h crypto.Hash, ok bool) {
+	for _, m := range hashToHashIdMapping {
+		if m.id == id {
+			return m.hash, true
+		}
+	}
+	return 0, false
+}
+
+// HashIdToHash returns an OpenPGP hash id which corresponds the given Hash.
+func HashToHashId(h crypto.Hash) (id byte, ok bool) {
+	for _, m := range hashToHashIdMapping {
+		if m.hash == h {
+			return m.id, true
+		}
+	}
+	return 0, false
+}
diff --git a/src/pkg/crypto/openpgp/s2k/s2k_test.go b/src/pkg/crypto/openpgp/s2k/s2k_test.go
new file mode 100644
index 000000000..ec4012c23
--- /dev/null
+++ b/src/pkg/crypto/openpgp/s2k/s2k_test.go
@@ -0,0 +1,118 @@
+// Copyright 2011 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package s2k
+
+import (
+	"bytes"
+	"crypto/sha1"
+	"crypto/rand"
+	"encoding/hex"
+	"testing"
+)
+
+var saltedTests = []struct {
+	in, out string
+}{
+	{"hello", "10295ac1"},
+	{"world", "ac587a5e"},
+	{"foo", "4dda8077"},
+	{"bar", "bd8aac6b9ea9cae04eae6a91c6133b58b5d9a61c14f355516ed9370456"},
+	{"x", "f1d3f289"},
+	{"xxxxxxxxxxxxxxxxxxxxxxx", "e00d7b45"},
+}
+
+func TestSalted(t *testing.T) {
+	h := sha1.New()
+	salt := [4]byte{1, 2, 3, 4}
+
+	for i, test := range saltedTests {
+		expected, _ := hex.DecodeString(test.out)
+		out := make([]byte, len(expected))
+		Salted(out, h, []byte(test.in), salt[:])
+		if !bytes.Equal(expected, out) {
+			t.Errorf("#%d, got: %x want: %x", i, out, expected)
+		}
+	}
+}
+
+var iteratedTests = []struct {
+	in, out string
+}{
+	{"hello", "83126105"},
+	{"world", "6fa317f9"},
+	{"foo", "8fbc35b9"},
+	{"bar", "2af5a99b54f093789fd657f19bd245af7604d0f6ae06f66602a46a08ae"},
+	{"x", "5a684dfe"},
+	{"xxxxxxxxxxxxxxxxxxxxxxx", "18955174"},
+}
+
+func TestIterated(t *testing.T) {
+	h := sha1.New()
+	salt := [4]byte{4, 3, 2, 1}
+
+	for i, test := range iteratedTests {
+		expected, _ := hex.DecodeString(test.out)
+		out := make([]byte, len(expected))
+		Iterated(out, h, []byte(test.in), salt[:], 31)
+		if !bytes.Equal(expected, out) {
+			t.Errorf("#%d, got: %x want: %x", i, out, expected)
+		}
+	}
+}
+
+var parseTests = []struct {
+	spec, in, out string
+}{
+	/* Simple with SHA1 */
+	{"0102", "hello", "aaf4c61d"},
+	/* Salted with SHA1 */
+	{"02020102030405060708", "hello", "f4f7d67e"},
+	/* Iterated with SHA1 */
+	{"03020102030405060708f1", "hello", "f2a57b7c"},
+}
+
+func TestParse(t *testing.T) {
+	for i, test := range parseTests {
+		spec, _ := hex.DecodeString(test.spec)
+		buf := bytes.NewBuffer(spec)
+		f, err := Parse(buf)
+		if err != nil {
+			t.Errorf("%d: Parse returned error: %s", i, err)
+			continue
+		}
+
+		expected, _ := hex.DecodeString(test.out)
+		out := make([]byte, len(expected))
+		f(out, []byte(test.in))
+		if !bytes.Equal(out, expected) {
+			t.Errorf("%d: output got: %x want: %x", i, out, expected)
+		}
+		if testing.Short() {
+			break
+		}
+	}
+}
+
+func TestSerialize(t *testing.T) {
+	buf := bytes.NewBuffer(nil)
+	key := make([]byte, 16)
+	passphrase := []byte("testing")
+	err := Serialize(buf, key, rand.Reader, passphrase)
+	if err != nil {
+		t.Errorf("failed to serialize: %s", err)
+		return
+	}
+
+	f, err := Parse(buf)
+	if err != nil {
+		t.Errorf("failed to reparse: %s", err)
+		return
+	}
+	key2 := make([]byte, len(key))
+	f(key2, passphrase)
+	if !bytes.Equal(key2, key) {
+		t.Errorf("keys don't match: %x (serialied) vs %x (parsed)", key, key2)
+	}
+}
diff --git a/src/pkg/crypto/openpgp/write.go b/src/pkg/crypto/openpgp/write.go
new file mode 100644
index 000000000..9884472ce
--- /dev/null
+++ b/src/pkg/crypto/openpgp/write.go
@@ -0,0 +1,308 @@
+// Copyright 2011 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package openpgp
+
+import (
+	"crypto"
+	"crypto/openpgp/armor"
+	"crypto/openpgp/error"
+	"crypto/openpgp/packet"
+	"crypto/openpgp/s2k"
+	"crypto/rand"
+	_ "crypto/sha256"
+	"hash"
+	"io"
+	"os"
+	"strconv"
+	"time"
+)
+
+// DetachSign signs message with the private key from signer (which must
+// already have been decrypted) and writes the signature to w.
+func DetachSign(w io.Writer, signer *Entity, message io.Reader) os.Error {
+	return detachSign(w, signer, message, packet.SigTypeBinary)
+}
+
+// ArmoredDetachSign signs message with the private key from signer (which
+// must already have been decrypted) and writes an armored signature to w.
+func ArmoredDetachSign(w io.Writer, signer *Entity, message io.Reader) (err os.Error) {
+	return armoredDetachSign(w, signer, message, packet.SigTypeBinary)
+}
+
+// DetachSignText signs message (after canonicalising the line endings) with
+// the private key from signer (which must already have been decrypted) and
+// writes the signature to w.
+func DetachSignText(w io.Writer, signer *Entity, message io.Reader) os.Error {
+	return detachSign(w, signer, message, packet.SigTypeText)
+}
+
+// ArmoredDetachSignText signs message (after canonicalising the line endings)
+// with the private key from signer (which must already have been decrypted)
+// and writes an armored signature to w.
+func ArmoredDetachSignText(w io.Writer, signer *Entity, message io.Reader) os.Error {
+	return armoredDetachSign(w, signer, message, packet.SigTypeText)
+}
+
+func armoredDetachSign(w io.Writer, signer *Entity, message io.Reader, sigType packet.SignatureType) (err os.Error) {
+	out, err := armor.Encode(w, SignatureType, nil)
+	if err != nil {
+		return
+	}
+	err = detachSign(out, signer, message, sigType)
+	if err != nil {
+		return
+	}
+	return out.Close()
+}
+
+func detachSign(w io.Writer, signer *Entity, message io.Reader, sigType packet.SignatureType) (err os.Error) {
+	if signer.PrivateKey == nil {
+		return error.InvalidArgumentError("signing key doesn't have a private key")
+	}
+	if signer.PrivateKey.Encrypted {
+		return error.InvalidArgumentError("signing key is encrypted")
+	}
+
+	sig := new(packet.Signature)
+	sig.SigType = sigType
+	sig.PubKeyAlgo = signer.PrivateKey.PubKeyAlgo
+	sig.Hash = crypto.SHA256
+	sig.CreationTime = uint32(time.Seconds())
+	sig.IssuerKeyId = &signer.PrivateKey.KeyId
+
+	h, wrappedHash, err := hashForSignature(sig.Hash, sig.SigType)
+	if err != nil {
+		return
+	}
+	io.Copy(wrappedHash, message)
+
+	err = sig.Sign(h, signer.PrivateKey)
+	if err != nil {
+		return
+	}
+
+	return sig.Serialize(w)
+}
+
+// FileHints contains metadata about encrypted files. This metadata is, itself,
+// encrypted.
+type FileHints struct {
+	// IsBinary can be set to hint that the contents are binary data.
+	IsBinary bool
+	// FileName hints at the name of the file that should be written. It's
+	// truncated to 255 bytes if longer. It may be empty to suggest that the
+	// file should not be written to disk. It may be equal to "_CONSOLE" to
+	// suggest the data should not be written to disk.
+	FileName string
+	// EpochSeconds contains the modification time of the file, or 0 if not applicable.
+	EpochSeconds uint32
+}
+
+// SymmetricallyEncrypt acts like gpg -c: it encrypts a file with a passphrase.
+// The resulting WriteCloser must be closed after the contents of the file have
+// been written.
+func SymmetricallyEncrypt(ciphertext io.Writer, passphrase []byte, hints *FileHints) (plaintext io.WriteCloser, err os.Error) {
+	if hints == nil {
+		hints = &FileHints{}
+	}
+
+	key, err := packet.SerializeSymmetricKeyEncrypted(ciphertext, rand.Reader, passphrase, packet.CipherAES128)
+	if err != nil {
+		return
+	}
+	w, err := packet.SerializeSymmetricallyEncrypted(ciphertext, packet.CipherAES128, key)
+	if err != nil {
+		return
+	}
+	return packet.SerializeLiteral(w, hints.IsBinary, hints.FileName, hints.EpochSeconds)
+}
+
+// intersectPreferences mutates and returns a prefix of a that contains only
+// the values in the intersection of a and b. The order of a is preserved.
+func intersectPreferences(a []uint8, b []uint8) (intersection []uint8) {
+	var j int
+	for _, v := range a {
+		for _, v2 := range b {
+			if v == v2 {
+				a[j] = v
+				j++
+				break
+			}
+		}
+	}
+
+	return a[:j]
+}
+
+func hashToHashId(h crypto.Hash) uint8 {
+	v, ok := s2k.HashToHashId(h)
+	if !ok {
+		panic("tried to convert unknown hash")
+	}
+	return v
+}
+
+// Encrypt encrypts a message to a number of recipients and, optionally, signs
+// it. hints contains optional information, that is also encrypted, that aids
+// the recipients in processing the message. The resulting WriteCloser must
+// be closed after the contents of the file have been written.
+func Encrypt(ciphertext io.Writer, to []*Entity, signed *Entity, hints *FileHints) (plaintext io.WriteCloser, err os.Error) {
+	var signer *packet.PrivateKey
+	if signed != nil {
+		signer = signed.signingKey().PrivateKey
+		if signer == nil || signer.Encrypted {
+			return nil, error.InvalidArgumentError("signing key must be decrypted")
+		}
+	}
+
+	// These are the possible ciphers that we'll use for the message.
+	candidateCiphers := []uint8{
+		uint8(packet.CipherAES128),
+		uint8(packet.CipherAES256),
+		uint8(packet.CipherCAST5),
+	}
+	// These are the possible hash functions that we'll use for the signature.
+	candidateHashes := []uint8{
+		hashToHashId(crypto.SHA256),
+		hashToHashId(crypto.SHA512),
+		hashToHashId(crypto.SHA1),
+		hashToHashId(crypto.RIPEMD160),
+	}
+	// In the event that a recipient doesn't specify any supported ciphers
+	// or hash functions, these are the ones that we assume that every
+	// implementation supports.
+	defaultCiphers := candidateCiphers[len(candidateCiphers)-1:]
+	defaultHashes := candidateHashes[len(candidateHashes)-1:]
+
+	encryptKeys := make([]Key, len(to))
+	for i := range to {
+		encryptKeys[i] = to[i].encryptionKey()
+		if encryptKeys[i].PublicKey == nil {
+			return nil, error.InvalidArgumentError("cannot encrypt a message to key id " + strconv.Uitob64(to[i].PrimaryKey.KeyId, 16) + " because it has no encryption keys")
+		}
+
+		sig := to[i].primaryIdentity().SelfSignature
+
+		preferredSymmetric := sig.PreferredSymmetric
+		if len(preferredSymmetric) == 0 {
+			preferredSymmetric = defaultCiphers
+		}
+		preferredHashes := sig.PreferredHash
+		if len(preferredHashes) == 0 {
+			preferredHashes = defaultHashes
+		}
+		candidateCiphers = intersectPreferences(candidateCiphers, preferredSymmetric)
+		candidateHashes = intersectPreferences(candidateHashes, preferredHashes)
+	}
+
+	if len(candidateCiphers) == 0 || len(candidateHashes) == 0 {
+		return nil, error.InvalidArgumentError("cannot encrypt because recipient set shares no common algorithms")
+	}
+
+	cipher := packet.CipherFunction(candidateCiphers[0])
+	hash, _ := s2k.HashIdToHash(candidateHashes[0])
+	symKey := make([]byte, cipher.KeySize())
+	if _, err := io.ReadFull(rand.Reader, symKey); err != nil {
+		return nil, err
+	}
+
+	for _, key := range encryptKeys {
+		if err := packet.SerializeEncryptedKey(ciphertext, rand.Reader, key.PublicKey, cipher, symKey); err != nil {
+			return nil, err
+		}
+	}
+
+	encryptedData, err := packet.SerializeSymmetricallyEncrypted(ciphertext, cipher, symKey)
+	if err != nil {
+		return
+	}
+
+	if signer != nil {
+		ops := &packet.OnePassSignature{
+			SigType:    packet.SigTypeBinary,
+			Hash:       hash,
+			PubKeyAlgo: signer.PubKeyAlgo,
+			KeyId:      signer.KeyId,
+			IsLast:     true,
+		}
+		if err := ops.Serialize(encryptedData); err != nil {
+			return nil, err
+		}
+	}
+
+	if hints == nil {
+		hints = &FileHints{}
+	}
+
+	w := encryptedData
+	if signer != nil {
+		// If we need to write a signature packet after the literal
+		// data then we need to stop literalData from closing
+		// encryptedData.
+		w = noOpCloser{encryptedData}
+
+	}
+	literalData, err := packet.SerializeLiteral(w, hints.IsBinary, hints.FileName, hints.EpochSeconds)
+	if err != nil {
+		return nil, err
+	}
+
+	if signer != nil {
+		return signatureWriter{encryptedData, literalData, hash, hash.New(), signer}, nil
+	}
+	return literalData, nil
+}
+
+// signatureWriter hashes the contents of a message while passing it along to
+// literalData. When closed, it closes literalData, writes a signature packet
+// to encryptedData and then also closes encryptedData.
+type signatureWriter struct {
+	encryptedData io.WriteCloser
+	literalData   io.WriteCloser
+	hashType      crypto.Hash
+	h             hash.Hash
+	signer        *packet.PrivateKey
+}
+
+func (s signatureWriter) Write(data []byte) (int, os.Error) {
+	s.h.Write(data)
+	return s.literalData.Write(data)
+}
+
+func (s signatureWriter) Close() os.Error {
+	sig := &packet.Signature{
+		SigType:      packet.SigTypeBinary,
+		PubKeyAlgo:   s.signer.PubKeyAlgo,
+		Hash:         s.hashType,
+		CreationTime: uint32(time.Seconds()),
+		IssuerKeyId:  &s.signer.KeyId,
+	}
+
+	if err := sig.Sign(s.h, s.signer); err != nil {
+		return err
+	}
+	if err := s.literalData.Close(); err != nil {
+		return err
+	}
+	if err := sig.Serialize(s.encryptedData); err != nil {
+		return err
+	}
+	return s.encryptedData.Close()
+}
+
+// noOpCloser is like an ioutil.NopCloser, but for an io.Writer.
+// TODO: we have two of these in OpenPGP packages alone. This probably needs
+// to be promoted somewhere more common.
+type noOpCloser struct {
+	w io.Writer
+}
+
+func (c noOpCloser) Write(data []byte) (n int, err os.Error) {
+	return c.w.Write(data)
+}
+
+func (c noOpCloser) Close() os.Error {
+	return nil
+}
diff --git a/src/pkg/crypto/openpgp/write_test.go b/src/pkg/crypto/openpgp/write_test.go
new file mode 100644
index 000000000..c542dfa45
--- /dev/null
+++ b/src/pkg/crypto/openpgp/write_test.go
@@ -0,0 +1,233 @@
+// Copyright 2011 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package openpgp
+
+import (
+	"bytes"
+	"crypto/rand"
+	"os"
+	"io"
+	"io/ioutil"
+	"testing"
+	"time"
+)
+
+func TestSignDetached(t *testing.T) {
+	kring, _ := ReadKeyRing(readerFromHex(testKeys1And2PrivateHex))
+	out := bytes.NewBuffer(nil)
+	message := bytes.NewBufferString(signedInput)
+	err := DetachSign(out, kring[0], message)
+	if err != nil {
+		t.Error(err)
+	}
+
+	testDetachedSignature(t, kring, out, signedInput, "check", testKey1KeyId)
+}
+
+func TestSignTextDetached(t *testing.T) {
+	kring, _ := ReadKeyRing(readerFromHex(testKeys1And2PrivateHex))
+	out := bytes.NewBuffer(nil)
+	message := bytes.NewBufferString(signedInput)
+	err := DetachSignText(out, kring[0], message)
+	if err != nil {
+		t.Error(err)
+	}
+
+	testDetachedSignature(t, kring, out, signedInput, "check", testKey1KeyId)
+}
+
+func TestSignDetachedDSA(t *testing.T) {
+	kring, _ := ReadKeyRing(readerFromHex(dsaTestKeyPrivateHex))
+	out := bytes.NewBuffer(nil)
+	message := bytes.NewBufferString(signedInput)
+	err := DetachSign(out, kring[0], message)
+	if err != nil {
+		t.Error(err)
+	}
+
+	testDetachedSignature(t, kring, out, signedInput, "check", testKey3KeyId)
+}
+
+func TestNewEntity(t *testing.T) {
+	if testing.Short() {
+		return
+	}
+
+	e, err := NewEntity(rand.Reader, time.Seconds(), "Test User", "test", "test@example.com")
+	if err != nil {
+		t.Errorf("failed to create entity: %s", err)
+		return
+	}
+
+	w := bytes.NewBuffer(nil)
+	if err := e.SerializePrivate(w); err != nil {
+		t.Errorf("failed to serialize entity: %s", err)
+		return
+	}
+	serialized := w.Bytes()
+
+	el, err := ReadKeyRing(w)
+	if err != nil {
+		t.Errorf("failed to reparse entity: %s", err)
+		return
+	}
+
+	if len(el) != 1 {
+		t.Errorf("wrong number of entities found, got %d, want 1", len(el))
+	}
+
+	w = bytes.NewBuffer(nil)
+	if err := e.SerializePrivate(w); err != nil {
+		t.Errorf("failed to serialize entity second time: %s", err)
+		return
+	}
+
+	if !bytes.Equal(w.Bytes(), serialized) {
+		t.Errorf("results differed")
+	}
+}
+
+func TestSymmetricEncryption(t *testing.T) {
+	buf := new(bytes.Buffer)
+	plaintext, err := SymmetricallyEncrypt(buf, []byte("testing"), nil)
+	if err != nil {
+		t.Errorf("error writing headers: %s", err)
+		return
+	}
+	message := []byte("hello world\n")
+	_, err = plaintext.Write(message)
+	if err != nil {
+		t.Errorf("error writing to plaintext writer: %s", err)
+	}
+	err = plaintext.Close()
+	if err != nil {
+		t.Errorf("error closing plaintext writer: %s", err)
+	}
+
+	md, err := ReadMessage(buf, nil, func(keys []Key, symmetric bool) ([]byte, os.Error) {
+		return []byte("testing"), nil
+	})
+	if err != nil {
+		t.Errorf("error rereading message: %s", err)
+	}
+	messageBuf := bytes.NewBuffer(nil)
+	_, err = io.Copy(messageBuf, md.UnverifiedBody)
+	if err != nil {
+		t.Errorf("error rereading message: %s", err)
+	}
+	if !bytes.Equal(message, messageBuf.Bytes()) {
+		t.Errorf("recovered message incorrect got '%s', want '%s'", messageBuf.Bytes(), message)
+	}
+}
+
+var testEncryptionTests = []struct {
+	keyRingHex string
+	isSigned   bool
+}{
+	{
+		testKeys1And2PrivateHex,
+		false,
+	},
+	{
+		testKeys1And2PrivateHex,
+		true,
+	},
+	{
+		dsaElGamalTestKeysHex,
+		false,
+	},
+	{
+		dsaElGamalTestKeysHex,
+		true,
+	},
+}
+
+func TestEncryption(t *testing.T) {
+	for i, test := range testEncryptionTests {
+		kring, _ := ReadKeyRing(readerFromHex(test.keyRingHex))
+
+		passphrase := []byte("passphrase")
+		for _, entity := range kring {
+			if entity.PrivateKey != nil && entity.PrivateKey.Encrypted {
+				err := entity.PrivateKey.Decrypt(passphrase)
+				if err != nil {
+					t.Errorf("#%d: failed to decrypt key", i)
+				}
+			}
+			for _, subkey := range entity.Subkeys {
+				if subkey.PrivateKey != nil && subkey.PrivateKey.Encrypted {
+					err := subkey.PrivateKey.Decrypt(passphrase)
+					if err != nil {
+						t.Errorf("#%d: failed to decrypt subkey", i)
+					}
+				}
+			}
+		}
+
+		var signed *Entity
+		if test.isSigned {
+			signed = kring[0]
+		}
+
+		buf := new(bytes.Buffer)
+		w, err := Encrypt(buf, kring[:1], signed, nil /* no hints */ )
+		if err != nil {
+			t.Errorf("#%d: error in Encrypt: %s", i, err)
+			continue
+		}
+
+		const message = "testing"
+		_, err = w.Write([]byte(message))
+		if err != nil {
+			t.Errorf("#%d: error writing plaintext: %s", i, err)
+			continue
+		}
+		err = w.Close()
+		if err != nil {
+			t.Errorf("#%d: error closing WriteCloser: %s", i, err)
+			continue
+		}
+
+		md, err := ReadMessage(buf, kring, nil /* no prompt */ )
+		if err != nil {
+			t.Errorf("#%d: error reading message: %s", i, err)
+			continue
+		}
+
+		if test.isSigned {
+			expectedKeyId := kring[0].signingKey().PublicKey.KeyId
+			if md.SignedByKeyId != expectedKeyId {
+				t.Errorf("#%d: message signed by wrong key id, got: %d, want: %d", i, *md.SignedBy, expectedKeyId)
+			}
+			if md.SignedBy == nil {
+				t.Errorf("#%d: failed to find the signing Entity", i)
+			}
+		}
+
+		plaintext, err := ioutil.ReadAll(md.UnverifiedBody)
+		if err != nil {
+			t.Errorf("#%d: error reading encrypted contents: %s", i, err)
+			continue
+		}
+
+		expectedKeyId := kring[0].encryptionKey().PublicKey.KeyId
+		if len(md.EncryptedToKeyIds) != 1 || md.EncryptedToKeyIds[0] != expectedKeyId {
+			t.Errorf("#%d: expected message to be encrypted to %v, but got %#v", i, expectedKeyId, md.EncryptedToKeyIds)
+		}
+
+		if string(plaintext) != message {
+			t.Errorf("#%d: got: %s, want: %s", i, string(plaintext), message)
+		}
+
+		if test.isSigned {
+			if md.SignatureError != nil {
+				t.Errorf("#%d: signature error: %s", i, err)
+			}
+			if md.Signature == nil {
+				t.Error("signature missing")
+			}
+		}
+	}
+}