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
/*
* dlls/rsaen/rc2.c
* RC2 functions
*
* Copyright 2004 Michael Jung
* Based on public domain code by Tom St Denis (tomstdenis@iahu.ca)
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
*/
/*
* This file contains code from the LibTomCrypt cryptographic
* library written by Tom St Denis (tomstdenis@iahu.ca). LibTomCrypt
* is in the public domain. The code in this file is tailored to
* special requirements. Take a look at http://libtomcrypt.org for the
* original version.
*/
#include "tomcrypt.h"
/* 256-entry permutation table, probably derived somehow from pi */
static const unsigned char permute[256] = {
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
};
int rc2_setup(const unsigned char *key, int keylen, int bits, int rounds, rc2_key *rc2)
{
unsigned *xkey = rc2->xkey;
unsigned char tmp[128];
unsigned T8, TM;
int i;
if (keylen < 5 || keylen > 128) {
return CRYPT_INVALID_KEYSIZE;
}
if (rounds != 0 && rounds != 16) {
return CRYPT_INVALID_ROUNDS;
}
/* Following comment is from Eric Young's rc2 code: */
/* It has come to my attention that there are 2 versions of the RC2
* key schedule. One which is normal, and anther which has a hook to
* use a reduced key length.
* BSAFE uses the 'retarded' version. What I previously shipped is
* the same as specifying 1024 for the 'bits' parameter. BSAFE uses
* a version where the bits parameter is the same as len*8 */
/* Seems like MS uses the 'retarded' version, too.
* Adjust effective keylen bits */
if (bits <= 0) bits = keylen << 3;
if (bits > 1024) bits = 1024;
for (i = 0; i < keylen; i++) {
tmp[i] = key[i] & 255;
}
/* Phase 1: Expand input key to 128 bytes */
if (keylen < 128) {
for (i = keylen; i < 128; i++) {
tmp[i] = permute[(tmp[i - 1] + tmp[i - keylen]) & 255];
}
}
/* Phase 2 - reduce effective key size to "bits" */
/*bits = keylen<<3; */
T8 = (unsigned)(bits+7)>>3;
TM = (255 >> (unsigned)(7 & -bits));
tmp[128 - T8] = permute[tmp[128 - T8] & TM];
for (i = 127 - T8; i >= 0; i--) {
tmp[i] = permute[tmp[i + 1] ^ tmp[i + T8]];
}
/* Phase 3 - copy to xkey in little-endian order */
for (i = 0; i < 64; i++) {
xkey[i] = (unsigned)tmp[2*i] + ((unsigned)tmp[2*i+1] << 8);
}
return CRYPT_OK;
}
/**********************************************************************\
* Encrypt an 8-byte block of plaintext using the given key. *
\**********************************************************************/
void rc2_ecb_encrypt( const unsigned char *plain,
unsigned char *cipher,
rc2_key *rc2)
{
unsigned *xkey;
unsigned x76, x54, x32, x10, i;
xkey = rc2->xkey;
x76 = ((unsigned)plain[7] << 8) + (unsigned)plain[6];
x54 = ((unsigned)plain[5] << 8) + (unsigned)plain[4];
x32 = ((unsigned)plain[3] << 8) + (unsigned)plain[2];
x10 = ((unsigned)plain[1] << 8) + (unsigned)plain[0];
for (i = 0; i < 16; i++) {
x10 = (x10 + (x32 & ~x76) + (x54 & x76) + xkey[4*i+0]) & 0xFFFF;
x10 = ((x10 << 1) | (x10 >> 15));
x32 = (x32 + (x54 & ~x10) + (x76 & x10) + xkey[4*i+1]) & 0xFFFF;
x32 = ((x32 << 2) | (x32 >> 14));
x54 = (x54 + (x76 & ~x32) + (x10 & x32) + xkey[4*i+2]) & 0xFFFF;
x54 = ((x54 << 3) | (x54 >> 13));
x76 = (x76 + (x10 & ~x54) + (x32 & x54) + xkey[4*i+3]) & 0xFFFF;
x76 = ((x76 << 5) | (x76 >> 11));
if (i == 4 || i == 10) {
x10 = (x10 + xkey[x76 & 63]) & 0xFFFF;
x32 = (x32 + xkey[x10 & 63]) & 0xFFFF;
x54 = (x54 + xkey[x32 & 63]) & 0xFFFF;
x76 = (x76 + xkey[x54 & 63]) & 0xFFFF;
}
}
cipher[0] = (unsigned char)x10;
cipher[1] = (unsigned char)(x10 >> 8);
cipher[2] = (unsigned char)x32;
cipher[3] = (unsigned char)(x32 >> 8);
cipher[4] = (unsigned char)x54;
cipher[5] = (unsigned char)(x54 >> 8);
cipher[6] = (unsigned char)x76;
cipher[7] = (unsigned char)(x76 >> 8);
}
/**********************************************************************\
* Decrypt an 8-byte block of ciphertext using the given key. *
\**********************************************************************/
void rc2_ecb_decrypt( const unsigned char *cipher,
unsigned char *plain,
rc2_key *rc2)
{
unsigned x76, x54, x32, x10;
unsigned *xkey;
int i;
xkey = rc2->xkey;
x76 = ((unsigned)cipher[7] << 8) + (unsigned)cipher[6];
x54 = ((unsigned)cipher[5] << 8) + (unsigned)cipher[4];
x32 = ((unsigned)cipher[3] << 8) + (unsigned)cipher[2];
x10 = ((unsigned)cipher[1] << 8) + (unsigned)cipher[0];
for (i = 15; i >= 0; i--) {
if (i == 4 || i == 10) {
x76 = (x76 - xkey[x54 & 63]) & 0xFFFF;
x54 = (x54 - xkey[x32 & 63]) & 0xFFFF;
x32 = (x32 - xkey[x10 & 63]) & 0xFFFF;
x10 = (x10 - xkey[x76 & 63]) & 0xFFFF;
}
x76 = ((x76 << 11) | (x76 >> 5));
x76 = (x76 - ((x10 & ~x54) + (x32 & x54) + xkey[4*i+3])) & 0xFFFF;
x54 = ((x54 << 13) | (x54 >> 3));
x54 = (x54 - ((x76 & ~x32) + (x10 & x32) + xkey[4*i+2])) & 0xFFFF;
x32 = ((x32 << 14) | (x32 >> 2));
x32 = (x32 - ((x54 & ~x10) + (x76 & x10) + xkey[4*i+1])) & 0xFFFF;
x10 = ((x10 << 15) | (x10 >> 1));
x10 = (x10 - ((x32 & ~x76) + (x54 & x76) + xkey[4*i+0])) & 0xFFFF;
}
plain[0] = (unsigned char)x10;
plain[1] = (unsigned char)(x10 >> 8);
plain[2] = (unsigned char)x32;
plain[3] = (unsigned char)(x32 >> 8);
plain[4] = (unsigned char)x54;
plain[5] = (unsigned char)(x54 >> 8);
plain[6] = (unsigned char)x76;
plain[7] = (unsigned char)(x76 >> 8);
}