Imported Upstream version 1.4upstream/1.4

1 files changed, 73 insertions, 0 deletions

diff --git a/src/crypto/des/cipher.go b/src/crypto/des/cipher.go
new file mode 100644
index 000000000..2f929ca7b
--- /dev/null
+++ b/src/crypto/des/cipher.go
@@ -0,0 +1,73 @@
+// 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 (
+	"crypto/cipher"
+	"strconv"
+)
+
+// The DES block size in bytes.
+const BlockSize = 8
+
+type KeySizeError int
+
+func (k KeySizeError) Error() string {
+	return "crypto/des: invalid key size " + strconv.Itoa(int(k))
+}
+
+// desCipher is an instance of DES encryption.
+type desCipher struct {
+	subkeys [16]uint64
+}
+
+// NewCipher creates and returns a new cipher.Block.
+func NewCipher(key []byte) (cipher.Block, error) {
+	if len(key) != 8 {
+		return nil, KeySizeError(len(key))
+	}
+
+	c := new(desCipher)
+	c.generateSubkeys(key)
+	return c, nil
+}
+
+func (c *desCipher) BlockSize() int { return BlockSize }
+
+func (c *desCipher) Encrypt(dst, src []byte) { encryptBlock(c.subkeys[:], dst, src) }
+
+func (c *desCipher) Decrypt(dst, src []byte) { decryptBlock(c.subkeys[:], dst, src) }
+
+// A tripleDESCipher is an instance of TripleDES encryption.
+type tripleDESCipher struct {
+	cipher1, cipher2, cipher3 desCipher
+}
+
+// NewTripleDESCipher creates and returns a new cipher.Block.
+func NewTripleDESCipher(key []byte) (cipher.Block, 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
+}
+
+func (c *tripleDESCipher) BlockSize() int { return BlockSize }
+
+func (c *tripleDESCipher) Encrypt(dst, src []byte) {
+	c.cipher1.Encrypt(dst, src)
+	c.cipher2.Decrypt(dst, dst)
+	c.cipher3.Encrypt(dst, dst)
+}
+
+func (c *tripleDESCipher) Decrypt(dst, src []byte) {
+	c.cipher3.Decrypt(dst, src)
+	c.cipher2.Encrypt(dst, dst)
+	c.cipher1.Decrypt(dst, dst)
+}