1 files changed, 155 insertions, 0 deletions
diff --git a/src/crypto/des/cipher.go b/src/crypto/des/cipher.go
new file mode 100644
index 0000000..ece764f
--- /dev/null
+++ b/src/crypto/des/cipher.go
@@ -0,0 +1,155 @@
+// 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"
+	"crypto/internal/alias"
+	"encoding/binary"
+	"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) {
+	if len(src) < BlockSize {
+		panic("crypto/des: input not full block")
+	}
+	if len(dst) < BlockSize {
+		panic("crypto/des: output not full block")
+	}
+	if alias.InexactOverlap(dst[:BlockSize], src[:BlockSize]) {
+		panic("crypto/des: invalid buffer overlap")
+	}
+	encryptBlock(c.subkeys[:], dst, src)
+}
+
+func (c *desCipher) Decrypt(dst, src []byte) {
+	if len(src) < BlockSize {
+		panic("crypto/des: input not full block")
+	}
+	if len(dst) < BlockSize {
+		panic("crypto/des: output not full block")
+	}
+	if alias.InexactOverlap(dst[:BlockSize], src[:BlockSize]) {
+		panic("crypto/des: invalid buffer overlap")
+	}
+	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) {
+	if len(src) < BlockSize {
+		panic("crypto/des: input not full block")
+	}
+	if len(dst) < BlockSize {
+		panic("crypto/des: output not full block")
+	}
+	if alias.InexactOverlap(dst[:BlockSize], src[:BlockSize]) {
+		panic("crypto/des: invalid buffer overlap")
+	}
+
+	b := binary.BigEndian.Uint64(src)
+	b = permuteInitialBlock(b)
+	left, right := uint32(b>>32), uint32(b)
+
+	left = (left << 1) | (left >> 31)
+	right = (right << 1) | (right >> 31)
+
+	for i := 0; i < 8; i++ {
+		left, right = feistel(left, right, c.cipher1.subkeys[2*i], c.cipher1.subkeys[2*i+1])
+	}
+	for i := 0; i < 8; i++ {
+		right, left = feistel(right, left, c.cipher2.subkeys[15-2*i], c.cipher2.subkeys[15-(2*i+1)])
+	}
+	for i := 0; i < 8; i++ {
+		left, right = feistel(left, right, c.cipher3.subkeys[2*i], c.cipher3.subkeys[2*i+1])
+	}
+
+	left = (left << 31) | (left >> 1)
+	right = (right << 31) | (right >> 1)
+
+	preOutput := (uint64(right) << 32) | uint64(left)
+	binary.BigEndian.PutUint64(dst, permuteFinalBlock(preOutput))
+}
+
+func (c *tripleDESCipher) Decrypt(dst, src []byte) {
+	if len(src) < BlockSize {
+		panic("crypto/des: input not full block")
+	}
+	if len(dst) < BlockSize {
+		panic("crypto/des: output not full block")
+	}
+	if alias.InexactOverlap(dst[:BlockSize], src[:BlockSize]) {
+		panic("crypto/des: invalid buffer overlap")
+	}
+
+	b := binary.BigEndian.Uint64(src)
+	b = permuteInitialBlock(b)
+	left, right := uint32(b>>32), uint32(b)
+
+	left = (left << 1) | (left >> 31)
+	right = (right << 1) | (right >> 31)
+
+	for i := 0; i < 8; i++ {
+		left, right = feistel(left, right, c.cipher3.subkeys[15-2*i], c.cipher3.subkeys[15-(2*i+1)])
+	}
+	for i := 0; i < 8; i++ {
+		right, left = feistel(right, left, c.cipher2.subkeys[2*i], c.cipher2.subkeys[2*i+1])
+	}
+	for i := 0; i < 8; i++ {
+		left, right = feistel(left, right, c.cipher1.subkeys[15-2*i], c.cipher1.subkeys[15-(2*i+1)])
+	}
+
+	left = (left << 31) | (left >> 1)
+	right = (right << 31) | (right >> 1)
+
+	preOutput := (uint64(right) << 32) | uint64(left)
+	binary.BigEndian.PutUint64(dst, permuteFinalBlock(preOutput))
+}