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Viewing changes to src/golang.org/x/crypto/pkcs12/internal/rc2/rc2.go

  • Committer: Nicholas Skaggs
  • Date: 2016-09-30 14:39:30 UTC
  • mfrom: (1.8.1)
  • Revision ID: nicholas.skaggs@canonical.com-20160930143930-vwwhrefh6ftckccy
import upstream

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src/golang.org/x/crypto/pkcs12/internal/rc2/rc2.go
 
1
// Copyright 2015 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.
 
4
 
 
5
// Package rc2 implements the RC2 cipher
 
6
/*
 
7
https://www.ietf.org/rfc/rfc2268.txt
 
8
http://people.csail.mit.edu/rivest/pubs/KRRR98.pdf
 
9
 
 
10
This code is licensed under the MIT license.
 
11
*/
 
12
package rc2
 
13
 
 
14
import (
 
15
        "crypto/cipher"
 
16
        "encoding/binary"
 
17
)
 
18
 
 
19
// The rc2 block size in bytes
 
20
const BlockSize = 8
 
21
 
 
22
type rc2Cipher struct {
 
23
        k [64]uint16
 
24
}
 
25
 
 
26
// New returns a new rc2 cipher with the given key and effective key length t1
 
27
func New(key []byte, t1 int) (cipher.Block, error) {
 
28
        // TODO(dgryski): error checking for key length
 
29
        return &rc2Cipher{
 
30
                k: expandKey(key, t1),
 
31
        }, nil
 
32
}
 
33
 
 
34
func (*rc2Cipher) BlockSize() int { return BlockSize }
 
35
 
 
36
var piTable = [256]byte{
 
37
        0xd9, 0x78, 0xf9, 0xc4, 0x19, 0xdd, 0xb5, 0xed, 0x28, 0xe9, 0xfd, 0x79, 0x4a, 0xa0, 0xd8, 0x9d,
 
38
        0xc6, 0x7e, 0x37, 0x83, 0x2b, 0x76, 0x53, 0x8e, 0x62, 0x4c, 0x64, 0x88, 0x44, 0x8b, 0xfb, 0xa2,
 
39
        0x17, 0x9a, 0x59, 0xf5, 0x87, 0xb3, 0x4f, 0x13, 0x61, 0x45, 0x6d, 0x8d, 0x09, 0x81, 0x7d, 0x32,
 
40
        0xbd, 0x8f, 0x40, 0xeb, 0x86, 0xb7, 0x7b, 0x0b, 0xf0, 0x95, 0x21, 0x22, 0x5c, 0x6b, 0x4e, 0x82,
 
41
        0x54, 0xd6, 0x65, 0x93, 0xce, 0x60, 0xb2, 0x1c, 0x73, 0x56, 0xc0, 0x14, 0xa7, 0x8c, 0xf1, 0xdc,
 
42
        0x12, 0x75, 0xca, 0x1f, 0x3b, 0xbe, 0xe4, 0xd1, 0x42, 0x3d, 0xd4, 0x30, 0xa3, 0x3c, 0xb6, 0x26,
 
43
        0x6f, 0xbf, 0x0e, 0xda, 0x46, 0x69, 0x07, 0x57, 0x27, 0xf2, 0x1d, 0x9b, 0xbc, 0x94, 0x43, 0x03,
 
44
        0xf8, 0x11, 0xc7, 0xf6, 0x90, 0xef, 0x3e, 0xe7, 0x06, 0xc3, 0xd5, 0x2f, 0xc8, 0x66, 0x1e, 0xd7,
 
45
        0x08, 0xe8, 0xea, 0xde, 0x80, 0x52, 0xee, 0xf7, 0x84, 0xaa, 0x72, 0xac, 0x35, 0x4d, 0x6a, 0x2a,
 
46
        0x96, 0x1a, 0xd2, 0x71, 0x5a, 0x15, 0x49, 0x74, 0x4b, 0x9f, 0xd0, 0x5e, 0x04, 0x18, 0xa4, 0xec,
 
47
        0xc2, 0xe0, 0x41, 0x6e, 0x0f, 0x51, 0xcb, 0xcc, 0x24, 0x91, 0xaf, 0x50, 0xa1, 0xf4, 0x70, 0x39,
 
48
        0x99, 0x7c, 0x3a, 0x85, 0x23, 0xb8, 0xb4, 0x7a, 0xfc, 0x02, 0x36, 0x5b, 0x25, 0x55, 0x97, 0x31,
 
49
        0x2d, 0x5d, 0xfa, 0x98, 0xe3, 0x8a, 0x92, 0xae, 0x05, 0xdf, 0x29, 0x10, 0x67, 0x6c, 0xba, 0xc9,
 
50
        0xd3, 0x00, 0xe6, 0xcf, 0xe1, 0x9e, 0xa8, 0x2c, 0x63, 0x16, 0x01, 0x3f, 0x58, 0xe2, 0x89, 0xa9,
 
51
        0x0d, 0x38, 0x34, 0x1b, 0xab, 0x33, 0xff, 0xb0, 0xbb, 0x48, 0x0c, 0x5f, 0xb9, 0xb1, 0xcd, 0x2e,
 
52
        0xc5, 0xf3, 0xdb, 0x47, 0xe5, 0xa5, 0x9c, 0x77, 0x0a, 0xa6, 0x20, 0x68, 0xfe, 0x7f, 0xc1, 0xad,
 
53
}
 
54
 
 
55
func expandKey(key []byte, t1 int) [64]uint16 {
 
56
 
 
57
        l := make([]byte, 128)
 
58
        copy(l, key)
 
59
 
 
60
        var t = len(key)
 
61
        var t8 = (t1 + 7) / 8
 
62
        var tm = byte(255 % uint(1<<(8+uint(t1)-8*uint(t8))))
 
63
 
 
64
        for i := len(key); i < 128; i++ {
 
65
                l[i] = piTable[l[i-1]+l[uint8(i-t)]]
 
66
        }
 
67
 
 
68
        l[128-t8] = piTable[l[128-t8]&tm]
 
69
 
 
70
        for i := 127 - t8; i >= 0; i-- {
 
71
                l[i] = piTable[l[i+1]^l[i+t8]]
 
72
        }
 
73
 
 
74
        var k [64]uint16
 
75
 
 
76
        for i := range k {
 
77
                k[i] = uint16(l[2*i]) + uint16(l[2*i+1])*256
 
78
        }
 
79
 
 
80
        return k
 
81
}
 
82
 
 
83
func rotl16(x uint16, b uint) uint16 {
 
84
        return (x >> (16 - b)) | (x << b)
 
85
}
 
86
 
 
87
func (c *rc2Cipher) Encrypt(dst, src []byte) {
 
88
 
 
89
        r0 := binary.LittleEndian.Uint16(src[0:])
 
90
        r1 := binary.LittleEndian.Uint16(src[2:])
 
91
        r2 := binary.LittleEndian.Uint16(src[4:])
 
92
        r3 := binary.LittleEndian.Uint16(src[6:])
 
93
 
 
94
        var j int
 
95
 
 
96
        for j <= 16 {
 
97
                // mix r0
 
98
                r0 = r0 + c.k[j] + (r3 & r2) + ((^r3) & r1)
 
99
                r0 = rotl16(r0, 1)
 
100
                j++
 
101
 
 
102
                // mix r1
 
103
                r1 = r1 + c.k[j] + (r0 & r3) + ((^r0) & r2)
 
104
                r1 = rotl16(r1, 2)
 
105
                j++
 
106
 
 
107
                // mix r2
 
108
                r2 = r2 + c.k[j] + (r1 & r0) + ((^r1) & r3)
 
109
                r2 = rotl16(r2, 3)
 
110
                j++
 
111
 
 
112
                // mix r3
 
113
                r3 = r3 + c.k[j] + (r2 & r1) + ((^r2) & r0)
 
114
                r3 = rotl16(r3, 5)
 
115
                j++
 
116
 
 
117
        }
 
118
 
 
119
        r0 = r0 + c.k[r3&63]
 
120
        r1 = r1 + c.k[r0&63]
 
121
        r2 = r2 + c.k[r1&63]
 
122
        r3 = r3 + c.k[r2&63]
 
123
 
 
124
        for j <= 40 {
 
125
 
 
126
                // mix r0
 
127
                r0 = r0 + c.k[j] + (r3 & r2) + ((^r3) & r1)
 
128
                r0 = rotl16(r0, 1)
 
129
                j++
 
130
 
 
131
                // mix r1
 
132
                r1 = r1 + c.k[j] + (r0 & r3) + ((^r0) & r2)
 
133
                r1 = rotl16(r1, 2)
 
134
                j++
 
135
 
 
136
                // mix r2
 
137
                r2 = r2 + c.k[j] + (r1 & r0) + ((^r1) & r3)
 
138
                r2 = rotl16(r2, 3)
 
139
                j++
 
140
 
 
141
                // mix r3
 
142
                r3 = r3 + c.k[j] + (r2 & r1) + ((^r2) & r0)
 
143
                r3 = rotl16(r3, 5)
 
144
                j++
 
145
 
 
146
        }
 
147
 
 
148
        r0 = r0 + c.k[r3&63]
 
149
        r1 = r1 + c.k[r0&63]
 
150
        r2 = r2 + c.k[r1&63]
 
151
        r3 = r3 + c.k[r2&63]
 
152
 
 
153
        for j <= 60 {
 
154
 
 
155
                // mix r0
 
156
                r0 = r0 + c.k[j] + (r3 & r2) + ((^r3) & r1)
 
157
                r0 = rotl16(r0, 1)
 
158
                j++
 
159
 
 
160
                // mix r1
 
161
                r1 = r1 + c.k[j] + (r0 & r3) + ((^r0) & r2)
 
162
                r1 = rotl16(r1, 2)
 
163
                j++
 
164
 
 
165
                // mix r2
 
166
                r2 = r2 + c.k[j] + (r1 & r0) + ((^r1) & r3)
 
167
                r2 = rotl16(r2, 3)
 
168
                j++
 
169
 
 
170
                // mix r3
 
171
                r3 = r3 + c.k[j] + (r2 & r1) + ((^r2) & r0)
 
172
                r3 = rotl16(r3, 5)
 
173
                j++
 
174
        }
 
175
 
 
176
        binary.LittleEndian.PutUint16(dst[0:], r0)
 
177
        binary.LittleEndian.PutUint16(dst[2:], r1)
 
178
        binary.LittleEndian.PutUint16(dst[4:], r2)
 
179
        binary.LittleEndian.PutUint16(dst[6:], r3)
 
180
}
 
181
 
 
182
func (c *rc2Cipher) Decrypt(dst, src []byte) {
 
183
 
 
184
        r0 := binary.LittleEndian.Uint16(src[0:])
 
185
        r1 := binary.LittleEndian.Uint16(src[2:])
 
186
        r2 := binary.LittleEndian.Uint16(src[4:])
 
187
        r3 := binary.LittleEndian.Uint16(src[6:])
 
188
 
 
189
        j := 63
 
190
 
 
191
        for j >= 44 {
 
192
                // unmix r3
 
193
                r3 = rotl16(r3, 16-5)
 
194
                r3 = r3 - c.k[j] - (r2 & r1) - ((^r2) & r0)
 
195
                j--
 
196
 
 
197
                // unmix r2
 
198
                r2 = rotl16(r2, 16-3)
 
199
                r2 = r2 - c.k[j] - (r1 & r0) - ((^r1) & r3)
 
200
                j--
 
201
 
 
202
                // unmix r1
 
203
                r1 = rotl16(r1, 16-2)
 
204
                r1 = r1 - c.k[j] - (r0 & r3) - ((^r0) & r2)
 
205
                j--
 
206
 
 
207
                // unmix r0
 
208
                r0 = rotl16(r0, 16-1)
 
209
                r0 = r0 - c.k[j] - (r3 & r2) - ((^r3) & r1)
 
210
                j--
 
211
        }
 
212
 
 
213
        r3 = r3 - c.k[r2&63]
 
214
        r2 = r2 - c.k[r1&63]
 
215
        r1 = r1 - c.k[r0&63]
 
216
        r0 = r0 - c.k[r3&63]
 
217
 
 
218
        for j >= 20 {
 
219
                // unmix r3
 
220
                r3 = rotl16(r3, 16-5)
 
221
                r3 = r3 - c.k[j] - (r2 & r1) - ((^r2) & r0)
 
222
                j--
 
223
 
 
224
                // unmix r2
 
225
                r2 = rotl16(r2, 16-3)
 
226
                r2 = r2 - c.k[j] - (r1 & r0) - ((^r1) & r3)
 
227
                j--
 
228
 
 
229
                // unmix r1
 
230
                r1 = rotl16(r1, 16-2)
 
231
                r1 = r1 - c.k[j] - (r0 & r3) - ((^r0) & r2)
 
232
                j--
 
233
 
 
234
                // unmix r0
 
235
                r0 = rotl16(r0, 16-1)
 
236
                r0 = r0 - c.k[j] - (r3 & r2) - ((^r3) & r1)
 
237
                j--
 
238
 
 
239
        }
 
240
 
 
241
        r3 = r3 - c.k[r2&63]
 
242
        r2 = r2 - c.k[r1&63]
 
243
        r1 = r1 - c.k[r0&63]
 
244
        r0 = r0 - c.k[r3&63]
 
245
 
 
246
        for j >= 0 {
 
247
 
 
248
                // unmix r3
 
249
                r3 = rotl16(r3, 16-5)
 
250
                r3 = r3 - c.k[j] - (r2 & r1) - ((^r2) & r0)
 
251
                j--
 
252
 
 
253
                // unmix r2
 
254
                r2 = rotl16(r2, 16-3)
 
255
                r2 = r2 - c.k[j] - (r1 & r0) - ((^r1) & r3)
 
256
                j--
 
257
 
 
258
                // unmix r1
 
259
                r1 = rotl16(r1, 16-2)
 
260
                r1 = r1 - c.k[j] - (r0 & r3) - ((^r0) & r2)
 
261
                j--
 
262
 
 
263
                // unmix r0
 
264
                r0 = rotl16(r0, 16-1)
 
265
                r0 = r0 - c.k[j] - (r3 & r2) - ((^r3) & r1)
 
266
                j--
 
267
 
 
268
        }
 
269
 
 
270
        binary.LittleEndian.PutUint16(dst[0:], r0)
 
271
        binary.LittleEndian.PutUint16(dst[2:], r1)
 
272
        binary.LittleEndian.PutUint16(dst[4:], r2)
 
273
        binary.LittleEndian.PutUint16(dst[6:], r3)
 
274
}