1 files changed, 92 insertions, 0 deletions
diff --git a/src/pkg/crypto/openpgp/write.go b/src/pkg/crypto/openpgp/write.go
new file mode 100644
index 000000000..1a2e2bf04
--- /dev/null
+++ b/src/pkg/crypto/openpgp/write.go
@@ -0,0 +1,92 @@
+// 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"
+	_ "crypto/sha256"
+	"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 SignTextDetachedArmored(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)
+
+	switch signer.PrivateKey.PubKeyAlgo {
+	case packet.PubKeyAlgoRSA, packet.PubKeyAlgoRSASignOnly:
+		priv := signer.PrivateKey.PrivateKey.(*rsa.PrivateKey)
+		err = sig.SignRSA(h, priv)
+	default:
+		err = error.UnsupportedError("public key algorithm: " + strconv.Itoa(int(sig.PubKeyAlgo)))
+	}
+
+	if err != nil {
+		return
+	}
+
+	return sig.Serialize(w)
+}