File size: 4,427 Bytes
4bcc2be | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 | // 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/fips140/alias"
"crypto/internal/fips140only"
"errors"
"internal/byteorder"
"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 fips140only.Enforced() {
return nil, errors.New("crypto/des: use of DES is not allowed in FIPS 140-only mode")
}
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")
}
cryptBlock(c.subkeys[:], dst, src, false)
}
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")
}
cryptBlock(c.subkeys[:], dst, src, true)
}
// 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 fips140only.Enforced() {
return nil, errors.New("crypto/des: use of TripleDES is not allowed in FIPS 140-only mode")
}
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 := byteorder.BEUint64(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)
byteorder.BEPutUint64(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 := byteorder.BEUint64(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)
byteorder.BEPutUint64(dst, permuteFinalBlock(preOutput))
}
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