1 // Copyright 2010 The Go Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style
3 // license that can be found in the LICENSE file.
5 // Package blowfish implements Bruce Schneier's Blowfish encryption algorithm.
6 package blowfish // import "golang.org/x/crypto/blowfish"
8 // The code is a port of Bruce Schneier's C implementation.
9 // See http://www.schneier.com/blowfish.html.
13 // The Blowfish block size in bytes.
16 // A Cipher is an instance of Blowfish encryption using a particular key.
19 s0, s1, s2, s3 [256]uint32
24 func (k KeySizeError) Error() string {
25 return "crypto/blowfish: invalid key size " + strconv.Itoa(int(k))
28 // NewCipher creates and returns a Cipher.
29 // The key argument should be the Blowfish key, from 1 to 56 bytes.
30 func NewCipher(key []byte) (*Cipher, error) {
32 if k := len(key); k < 1 || k > 56 {
33 return nil, KeySizeError(k)
36 ExpandKey(key, &result)
40 // NewSaltedCipher creates a returns a Cipher that folds a salt into its key
41 // schedule. For most purposes, NewCipher, instead of NewSaltedCipher, is
42 // sufficient and desirable. For bcrypt compatibility, the key can be over 56
44 func NewSaltedCipher(key, salt []byte) (*Cipher, error) {
49 if k := len(key); k < 1 {
50 return nil, KeySizeError(k)
53 expandKeyWithSalt(key, salt, &result)
57 // BlockSize returns the Blowfish block size, 8 bytes.
58 // It is necessary to satisfy the Block interface in the
59 // package "crypto/cipher".
60 func (c *Cipher) BlockSize() int { return BlockSize }
62 // Encrypt encrypts the 8-byte buffer src using the key k
63 // and stores the result in dst.
64 // Note that for amounts of data larger than a block,
65 // it is not safe to just call Encrypt on successive blocks;
66 // instead, use an encryption mode like CBC (see crypto/cipher/cbc.go).
67 func (c *Cipher) Encrypt(dst, src []byte) {
68 l := uint32(src[0])<<24 | uint32(src[1])<<16 | uint32(src[2])<<8 | uint32(src[3])
69 r := uint32(src[4])<<24 | uint32(src[5])<<16 | uint32(src[6])<<8 | uint32(src[7])
70 l, r = encryptBlock(l, r, c)
71 dst[0], dst[1], dst[2], dst[3] = byte(l>>24), byte(l>>16), byte(l>>8), byte(l)
72 dst[4], dst[5], dst[6], dst[7] = byte(r>>24), byte(r>>16), byte(r>>8), byte(r)
75 // Decrypt decrypts the 8-byte buffer src using the key k
76 // and stores the result in dst.
77 func (c *Cipher) Decrypt(dst, src []byte) {
78 l := uint32(src[0])<<24 | uint32(src[1])<<16 | uint32(src[2])<<8 | uint32(src[3])
79 r := uint32(src[4])<<24 | uint32(src[5])<<16 | uint32(src[6])<<8 | uint32(src[7])
80 l, r = decryptBlock(l, r, c)
81 dst[0], dst[1], dst[2], dst[3] = byte(l>>24), byte(l>>16), byte(l>>8), byte(l)
82 dst[4], dst[5], dst[6], dst[7] = byte(r>>24), byte(r>>16), byte(r>>8), byte(r)
85 func initCipher(c *Cipher) {
87 copy(c.s0[0:], s0[0:])
88 copy(c.s1[0:], s1[0:])
89 copy(c.s2[0:], s2[0:])
90 copy(c.s3[0:], s3[0:])