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
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
|
/* arctwo.c --- The RC2 cipher as described in RFC 2268.
* Copyright (C) 2003-2006, 2008-2015 Free Software Foundation, Inc.
*
* This file is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published
* by the Free Software Foundation; either version 2, or (at your
* option) any later version.
*
* This file is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this file; if not, see <http://www.gnu.org/licenses/>.
*/
/* Code from GnuTLS/Libgcrypt adapted for gnulib by Simon Josefsson. */
/* This implementation was written by Nikos Mavroyanopoulos for GNUTLS
* as a Libgcrypt module (gnutls/lib/x509/rc2.c) and later adapted for
* direct use by Libgcrypt by Werner Koch. This implementation is
* only useful for pkcs#12 decryption.
*
* The implementation here is based on Peter Gutmann's RRC.2 paper.
*/
#include <config.h>
#include "arctwo.h"
#include "bitrotate.h"
static const uint8_t arctwo_sbox[] = {
217, 120, 249, 196, 25, 221, 181, 237,
40, 233, 253, 121, 74, 160, 216, 157,
198, 126, 55, 131, 43, 118, 83, 142,
98, 76, 100, 136, 68, 139, 251, 162,
23, 154, 89, 245, 135, 179, 79, 19,
97, 69, 109, 141, 9, 129, 125, 50,
189, 143, 64, 235, 134, 183, 123, 11,
240, 149, 33, 34, 92, 107, 78, 130,
84, 214, 101, 147, 206, 96, 178, 28,
115, 86, 192, 20, 167, 140, 241, 220,
18, 117, 202, 31, 59, 190, 228, 209,
66, 61, 212, 48, 163, 60, 182, 38,
111, 191, 14, 218, 70, 105, 7, 87,
39, 242, 29, 155, 188, 148, 67, 3,
248, 17, 199, 246, 144, 239, 62, 231,
6, 195, 213, 47, 200, 102, 30, 215,
8, 232, 234, 222, 128, 82, 238, 247,
132, 170, 114, 172, 53, 77, 106, 42,
150, 26, 210, 113, 90, 21, 73, 116,
75, 159, 208, 94, 4, 24, 164, 236,
194, 224, 65, 110, 15, 81, 203, 204,
36, 145, 175, 80, 161, 244, 112, 57,
153, 124, 58, 133, 35, 184, 180, 122,
252, 2, 54, 91, 37, 85, 151, 49,
45, 93, 250, 152, 227, 138, 146, 174,
5, 223, 41, 16, 103, 108, 186, 201,
211, 0, 230, 207, 225, 158, 168, 44,
99, 22, 1, 63, 88, 226, 137, 169,
13, 56, 52, 27, 171, 51, 255, 176,
187, 72, 12, 95, 185, 177, 205, 46,
197, 243, 219, 71, 229, 165, 156, 119,
10, 166, 32, 104, 254, 127, 193, 173
};
/* C89 compliant way to cast 'char' to 'unsigned char'. */
static unsigned char
to_uchar (char ch)
{
return ch;
}
void
arctwo_encrypt (arctwo_context *context, const char *inbuf,
char *outbuf, size_t length)
{
for (; length >= ARCTWO_BLOCK_SIZE; length -= ARCTWO_BLOCK_SIZE,
inbuf += ARCTWO_BLOCK_SIZE, outbuf += ARCTWO_BLOCK_SIZE)
{
size_t i, j;
uint16_t word0 = 0, word1 = 0, word2 = 0, word3 = 0;
word0 = (word0 << 8) | to_uchar (inbuf[1]);
word0 = (word0 << 8) | to_uchar (inbuf[0]);
word1 = (word1 << 8) | to_uchar (inbuf[3]);
word1 = (word1 << 8) | to_uchar (inbuf[2]);
word2 = (word2 << 8) | to_uchar (inbuf[5]);
word2 = (word2 << 8) | to_uchar (inbuf[4]);
word3 = (word3 << 8) | to_uchar (inbuf[7]);
word3 = (word3 << 8) | to_uchar (inbuf[6]);
for (i = 0; i < 16; i++)
{
j = i * 4;
/* For some reason I cannot combine those steps. */
word0 += (word1 & ~word3) + (word2 & word3) + context->S[j];
word0 = rotl16 (word0, 1);
word1 += (word2 & ~word0) + (word3 & word0) + context->S[j + 1];
word1 = rotl16 (word1, 2);
word2 += (word3 & ~word1) + (word0 & word1) + context->S[j + 2];
word2 = rotl16 (word2, 3);
word3 += (word0 & ~word2) + (word1 & word2) + context->S[j + 3];
word3 = rotl16 (word3, 5);
if (i == 4 || i == 10)
{
word0 += context->S[word3 & 63];
word1 += context->S[word0 & 63];
word2 += context->S[word1 & 63];
word3 += context->S[word2 & 63];
}
}
outbuf[0] = word0 & 255;
outbuf[1] = word0 >> 8;
outbuf[2] = word1 & 255;
outbuf[3] = word1 >> 8;
outbuf[4] = word2 & 255;
outbuf[5] = word2 >> 8;
outbuf[6] = word3 & 255;
outbuf[7] = word3 >> 8;
}
}
void
arctwo_decrypt (arctwo_context *context, const char *inbuf,
char *outbuf, size_t length)
{
for (; length >= ARCTWO_BLOCK_SIZE; length -= ARCTWO_BLOCK_SIZE,
inbuf += ARCTWO_BLOCK_SIZE, outbuf += ARCTWO_BLOCK_SIZE)
{
size_t i, j;
uint16_t word0 = 0, word1 = 0, word2 = 0, word3 = 0;
word0 = (word0 << 8) | to_uchar (inbuf[1]);
word0 = (word0 << 8) | to_uchar (inbuf[0]);
word1 = (word1 << 8) | to_uchar (inbuf[3]);
word1 = (word1 << 8) | to_uchar (inbuf[2]);
word2 = (word2 << 8) | to_uchar (inbuf[5]);
word2 = (word2 << 8) | to_uchar (inbuf[4]);
word3 = (word3 << 8) | to_uchar (inbuf[7]);
word3 = (word3 << 8) | to_uchar (inbuf[6]);
for (i = 16; i > 0; i--)
{
j = (i - 1) * 4;
word3 = rotr16 (word3, 5);
word3 -= (word0 & ~word2) + (word1 & word2) + context->S[j + 3];
word2 = rotr16 (word2, 3);
word2 -= (word3 & ~word1) + (word0 & word1) + context->S[j + 2];
word1 = rotr16 (word1, 2);
word1 -= (word2 & ~word0) + (word3 & word0) + context->S[j + 1];
word0 = rotr16 (word0, 1);
word0 -= (word1 & ~word3) + (word2 & word3) + context->S[j];
if (i == 6 || i == 12)
{
word3 = word3 - context->S[word2 & 63];
word2 = word2 - context->S[word1 & 63];
word1 = word1 - context->S[word0 & 63];
word0 = word0 - context->S[word3 & 63];
}
}
outbuf[0] = word0 & 255;
outbuf[1] = word0 >> 8;
outbuf[2] = word1 & 255;
outbuf[3] = word1 >> 8;
outbuf[4] = word2 & 255;
outbuf[5] = word2 >> 8;
outbuf[6] = word3 & 255;
outbuf[7] = word3 >> 8;
}
}
void
arctwo_setkey_ekb (arctwo_context *context,
size_t keylen, const char *key, size_t effective_keylen)
{
size_t i;
uint8_t *S, x;
if (keylen < 40 / 8 || effective_keylen > 1024)
return;
S = (uint8_t *) context->S;
for (i = 0; i < keylen; i++)
S[i] = (uint8_t) key[i];
for (i = keylen; i < 128; i++)
S[i] = arctwo_sbox[(S[i - keylen] + S[i - 1]) & 255];
S[0] = arctwo_sbox[S[0]];
/* Phase 2 - reduce effective key size to "bits". This was not
* discussed in Gutmann's paper. I've copied that from the public
* domain code posted in sci.crypt. */
if (effective_keylen)
{
size_t len = (effective_keylen + 7) >> 3;
i = 128 - len;
x = arctwo_sbox[S[i] & (255 >> (7 & -effective_keylen))];
S[i] = x;
while (i--)
{
x = arctwo_sbox[x ^ S[i + len]];
S[i] = x;
}
}
/* Make the expanded key, endian independent. */
for (i = 0; i < 64; i++)
context->S[i] = ((uint16_t) S[i * 2] | (((uint16_t) S[i * 2 + 1]) << 8));
}
|
