1 files changed, 103 insertions, 0 deletions
diff --git a/src/pkg/crypto/des/cipher.go b/src/pkg/crypto/des/cipher.go
new file mode 100644
index 000000000..d17a1a783
--- /dev/null
+++ b/src/pkg/crypto/des/cipher.go
@@ -0,0 +1,103 @@
+// 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 des
+
+import (
+	"os"
+	"strconv"
+)
+
+// The DES block size in bytes.
+const BlockSize = 8
+
+type KeySizeError int
+
+func (k KeySizeError) String() string {
+	return "crypto/des: invalid key size " + strconv.Itoa(int(k))
+}
+
+// Cipher is an instance of DES encryption.
+type Cipher struct {
+	subkeys [16]uint64
+}
+
+// NewCipher creates and returns a new Cipher.
+func NewCipher(key []byte) (*Cipher, os.Error) {
+	if len(key) != 8 {
+		return nil, KeySizeError(len(key))
+	}
+
+	c := new(Cipher)
+	c.generateSubkeys(key)
+	return c, nil
+}
+
+// BlockSize returns the DES block size, 8 bytes.
+func (c *Cipher) BlockSize() int { return BlockSize }
+
+// Encrypts the 8-byte buffer src and stores the result in dst.
+// Note that for amounts of data larger than a block,
+// it is not safe to just call Encrypt on successive blocks;
+// instead, use an encryption mode like CBC (see crypto/cipher/cbc.go).
+func (c *Cipher) Encrypt(dst, src []byte) { encryptBlock(c.subkeys[:], dst, src) }
+
+// Decrypts the 8-byte buffer src and stores the result in dst.
+func (c *Cipher) Decrypt(dst, src []byte) { decryptBlock(c.subkeys[:], dst, src) }
+
+// Reset zeros the key data, so that it will no longer
+// appear in the process's memory.
+func (c *Cipher) Reset() {
+	for i := 0; i < len(c.subkeys); i++ {
+		c.subkeys[i] = 0
+	}
+}
+
+// A TripleDESCipher is an instance of TripleDES encryption.
+type TripleDESCipher struct {
+	cipher1, cipher2, cipher3 Cipher
+}
+
+// NewCipher creates and returns a new Cipher.
+func NewTripleDESCipher(key []byte) (*TripleDESCipher, os.Error) {
+	if len(key) != 24 {
+		return nil, KeySizeError(len(key))
+	}
+
+	c := new(TripleDESCipher)
+	c.cipher1.generateSubkeys(key[:8])
+	c.cipher2.generateSubkeys(key[8:16])
+	c.cipher3.generateSubkeys(key[16:])
+	return c, nil
+}
+
+// BlockSize returns the TripleDES block size, 8 bytes.
+// It is necessary to satisfy the Block interface in the
+// package "crypto/cipher".
+func (c *TripleDESCipher) BlockSize() int { return BlockSize }
+
+// Encrypts the 8-byte buffer src and stores the result in dst.
+// Note that for amounts of data larger than a block,
+// it is not safe to just call Encrypt on successive blocks;
+// instead, use an encryption mode like CBC (see crypto/cipher/cbc.go).
+func (c *TripleDESCipher) Encrypt(dst, src []byte) {
+	c.cipher1.Encrypt(dst, src)
+	c.cipher2.Decrypt(dst, dst)
+	c.cipher3.Encrypt(dst, dst)
+}
+
+// Decrypts the 8-byte buffer src and stores the result in dst.
+func (c *TripleDESCipher) Decrypt(dst, src []byte) {
+	c.cipher3.Decrypt(dst, src)
+	c.cipher2.Encrypt(dst, dst)
+	c.cipher1.Decrypt(dst, dst)
+}
+
+// Reset zeros the key data, so that it will no longer
+// appear in the process's memory.
+func (c *TripleDESCipher) Reset() {
+	c.cipher1.Reset()
+	c.cipher2.Reset()
+	c.cipher3.Reset()
+}