| 1 | /* |
| 2 | * Copyright (c) 2004 Kungliga Tekniska Högskolan |
| 3 | * (Royal Institute of Technology, Stockholm, Sweden). |
| 4 | * All rights reserved. |
| 5 | * |
| 6 | * Redistribution and use in source and binary forms, with or without |
| 7 | * modification, are permitted provided that the following conditions |
| 8 | * are met: |
| 9 | * |
| 10 | * 1. Redistributions of source code must retain the above copyright |
| 11 | * notice, this list of conditions and the following disclaimer. |
| 12 | * |
| 13 | * 2. Redistributions in binary form must reproduce the above copyright |
| 14 | * notice, this list of conditions and the following disclaimer in the |
| 15 | * documentation and/or other materials provided with the distribution. |
| 16 | * |
| 17 | * 3. Neither the name of the Institute nor the names of its contributors |
| 18 | * may be used to endorse or promote products derived from this software |
| 19 | * without specific prior written permission. |
| 20 | * |
| 21 | * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND |
| 22 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| 23 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| 24 | * ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE |
| 25 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
| 26 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
| 27 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
| 28 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
| 29 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
| 30 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
| 31 | * SUCH DAMAGE. |
| 32 | */ |
| 33 | |
| 34 | #include <config.h> |
| 35 | |
| 36 | #include "rc2.h" |
| 37 | #include <stdio.h> |
| 38 | #include <stdlib.h> |
| 39 | #include <string.h> |
| 40 | |
| 41 | /* |
| 42 | * Implemented from Peter Gutmann's "Specification for Ron Rivests Cipher No.2" |
| 43 | * rfc2268 and "On the Design and Security of RC2" was also useful. |
| 44 | */ |
| 45 | |
| 46 | static unsigned int Sbox[256] = { |
| 47 | 0xd9, 0x78, 0xf9, 0xc4, 0x19, 0xdd, 0xb5, 0xed, |
| 48 | 0x28, 0xe9, 0xfd, 0x79, 0x4a, 0xa0, 0xd8, 0x9d, |
| 49 | 0xc6, 0x7e, 0x37, 0x83, 0x2b, 0x76, 0x53, 0x8e, |
| 50 | 0x62, 0x4c, 0x64, 0x88, 0x44, 0x8b, 0xfb, 0xa2, |
| 51 | 0x17, 0x9a, 0x59, 0xf5, 0x87, 0xb3, 0x4f, 0x13, |
| 52 | 0x61, 0x45, 0x6d, 0x8d, 0x09, 0x81, 0x7d, 0x32, |
| 53 | 0xbd, 0x8f, 0x40, 0xeb, 0x86, 0xb7, 0x7b, 0x0b, |
| 54 | 0xf0, 0x95, 0x21, 0x22, 0x5c, 0x6b, 0x4e, 0x82, |
| 55 | 0x54, 0xd6, 0x65, 0x93, 0xce, 0x60, 0xb2, 0x1c, |
| 56 | 0x73, 0x56, 0xc0, 0x14, 0xa7, 0x8c, 0xf1, 0xdc, |
| 57 | 0x12, 0x75, 0xca, 0x1f, 0x3b, 0xbe, 0xe4, 0xd1, |
| 58 | 0x42, 0x3d, 0xd4, 0x30, 0xa3, 0x3c, 0xb6, 0x26, |
| 59 | 0x6f, 0xbf, 0x0e, 0xda, 0x46, 0x69, 0x07, 0x57, |
| 60 | 0x27, 0xf2, 0x1d, 0x9b, 0xbc, 0x94, 0x43, 0x03, |
| 61 | 0xf8, 0x11, 0xc7, 0xf6, 0x90, 0xef, 0x3e, 0xe7, |
| 62 | 0x06, 0xc3, 0xd5, 0x2f, 0xc8, 0x66, 0x1e, 0xd7, |
| 63 | 0x08, 0xe8, 0xea, 0xde, 0x80, 0x52, 0xee, 0xf7, |
| 64 | 0x84, 0xaa, 0x72, 0xac, 0x35, 0x4d, 0x6a, 0x2a, |
| 65 | 0x96, 0x1a, 0xd2, 0x71, 0x5a, 0x15, 0x49, 0x74, |
| 66 | 0x4b, 0x9f, 0xd0, 0x5e, 0x04, 0x18, 0xa4, 0xec, |
| 67 | 0xc2, 0xe0, 0x41, 0x6e, 0x0f, 0x51, 0xcb, 0xcc, |
| 68 | 0x24, 0x91, 0xaf, 0x50, 0xa1, 0xf4, 0x70, 0x39, |
| 69 | 0x99, 0x7c, 0x3a, 0x85, 0x23, 0xb8, 0xb4, 0x7a, |
| 70 | 0xfc, 0x02, 0x36, 0x5b, 0x25, 0x55, 0x97, 0x31, |
| 71 | 0x2d, 0x5d, 0xfa, 0x98, 0xe3, 0x8a, 0x92, 0xae, |
| 72 | 0x05, 0xdf, 0x29, 0x10, 0x67, 0x6c, 0xba, 0xc9, |
| 73 | 0xd3, 0x00, 0xe6, 0xcf, 0xe1, 0x9e, 0xa8, 0x2c, |
| 74 | 0x63, 0x16, 0x01, 0x3f, 0x58, 0xe2, 0x89, 0xa9, |
| 75 | 0x0d, 0x38, 0x34, 0x1b, 0xab, 0x33, 0xff, 0xb0, |
| 76 | 0xbb, 0x48, 0x0c, 0x5f, 0xb9, 0xb1, 0xcd, 0x2e, |
| 77 | 0xc5, 0xf3, 0xdb, 0x47, 0xe5, 0xa5, 0x9c, 0x77, |
| 78 | 0x0a, 0xa6, 0x20, 0x68, 0xfe, 0x7f, 0xc1, 0xad |
| 79 | }; |
| 80 | |
| 81 | void |
| 82 | RC2_set_key(RC2_KEY *key, int len, const unsigned char *data, int bits) |
| 83 | { |
| 84 | unsigned char k[128]; |
| 85 | int j, T8, TM; |
| 86 | |
| 87 | if (len <= 0) |
| 88 | abort(); |
| 89 | if (len > 128) |
| 90 | len = 128; |
| 91 | if (bits <= 0 || bits > 1024) |
| 92 | bits = 1024; |
| 93 | |
| 94 | for (j = 0; j < len; j++) |
| 95 | k[j] = data[j]; |
| 96 | for (; j < 128; j++) |
| 97 | k[j] = Sbox[(k[j - len] + k[j - 1]) & 0xff]; |
| 98 | |
| 99 | T8 = (bits + 7) / 8; |
| 100 | j = (8*T8 - bits); |
| 101 | TM = 0xff >> j; |
| 102 | |
| 103 | k[128 - T8] = Sbox[k[128 - T8] & TM]; |
| 104 | |
| 105 | for (j = 127 - T8; j >= 0; j--) |
| 106 | k[j] = Sbox[k[j + 1] ^ k[j + T8]]; |
| 107 | |
| 108 | for (j = 0; j < 64; j++) |
| 109 | key->data[j] = k[(j * 2) + 0] | (k[(j * 2) + 1] << 8); |
| 110 | memset(k, 0, sizeof(k)); |
| 111 | } |
| 112 | |
| 113 | #define ROT16L(w,n) ((w<<n)|(w>>(16-n))) |
| 114 | #define ROT16R(w,n) ((w>>n)|(w<<(16-n))) |
| 115 | |
| 116 | void |
| 117 | RC2_encryptc(unsigned char *in, unsigned char *out, const RC2_KEY *key) |
| 118 | { |
| 119 | int i, j; |
| 120 | int w0, w1, w2, w3; |
| 121 | int t0, t1, t2, t3; |
| 122 | |
| 123 | w0 = in[0] | (in[1] << 8); |
| 124 | w1 = in[2] | (in[3] << 8); |
| 125 | w2 = in[4] | (in[5] << 8); |
| 126 | w3 = in[6] | (in[7] << 8); |
| 127 | |
| 128 | for (i = 0; i < 16; i++) { |
| 129 | j = i * 4; |
| 130 | t0 = (w0 + (w1 & ~w3) + (w2 & w3) + key->data[j + 0]) & 0xffff; |
| 131 | w0 = ROT16L(t0, 1); |
| 132 | t1 = (w1 + (w2 & ~w0) + (w3 & w0) + key->data[j + 1]) & 0xffff; |
| 133 | w1 = ROT16L(t1, 2); |
| 134 | t2 = (w2 + (w3 & ~w1) + (w0 & w1) + key->data[j + 2]) & 0xffff; |
| 135 | w2 = ROT16L(t2, 3); |
| 136 | t3 = (w3 + (w0 & ~w2) + (w1 & w2) + key->data[j + 3]) & 0xffff; |
| 137 | w3 = ROT16L(t3, 5); |
| 138 | if(i == 4 || i == 10) { |
| 139 | w0 += key->data[w3 & 63]; |
| 140 | w1 += key->data[w0 & 63]; |
| 141 | w2 += key->data[w1 & 63]; |
| 142 | w3 += key->data[w2 & 63]; |
| 143 | } |
| 144 | } |
| 145 | |
| 146 | out[0] = w0 & 0xff; |
| 147 | out[1] = (w0 >> 8) & 0xff; |
| 148 | out[2] = w1 & 0xff; |
| 149 | out[3] = (w1 >> 8) & 0xff; |
| 150 | out[4] = w2 & 0xff; |
| 151 | out[5] = (w2 >> 8) & 0xff; |
| 152 | out[6] = w3 & 0xff; |
| 153 | out[7] = (w3 >> 8) & 0xff; |
| 154 | } |
| 155 | |
| 156 | void |
| 157 | RC2_decryptc(unsigned char *in, unsigned char *out, const RC2_KEY *key) |
| 158 | { |
| 159 | int i, j; |
| 160 | int w0, w1, w2, w3; |
| 161 | int t0, t1, t2, t3; |
| 162 | |
| 163 | w0 = in[0] | (in[1] << 8); |
| 164 | w1 = in[2] | (in[3] << 8); |
| 165 | w2 = in[4] | (in[5] << 8); |
| 166 | w3 = in[6] | (in[7] << 8); |
| 167 | |
| 168 | for (i = 15; i >= 0; i--) { |
| 169 | j = i * 4; |
| 170 | |
| 171 | if(i == 4 || i == 10) { |
| 172 | w3 = (w3 - key->data[w2 & 63]) & 0xffff; |
| 173 | w2 = (w2 - key->data[w1 & 63]) & 0xffff; |
| 174 | w1 = (w1 - key->data[w0 & 63]) & 0xffff; |
| 175 | w0 = (w0 - key->data[w3 & 63]) & 0xffff; |
| 176 | } |
| 177 | |
| 178 | t3 = ROT16R(w3, 5); |
| 179 | w3 = (t3 - (w0 & ~w2) - (w1 & w2) - key->data[j + 3]) & 0xffff; |
| 180 | t2 = ROT16R(w2, 3); |
| 181 | w2 = (t2 - (w3 & ~w1) - (w0 & w1) - key->data[j + 2]) & 0xffff; |
| 182 | t1 = ROT16R(w1, 2); |
| 183 | w1 = (t1 - (w2 & ~w0) - (w3 & w0) - key->data[j + 1]) & 0xffff; |
| 184 | t0 = ROT16R(w0, 1); |
| 185 | w0 = (t0 - (w1 & ~w3) - (w2 & w3) - key->data[j + 0]) & 0xffff; |
| 186 | |
| 187 | } |
| 188 | out[0] = w0 & 0xff; |
| 189 | out[1] = (w0 >> 8) & 0xff; |
| 190 | out[2] = w1 & 0xff; |
| 191 | out[3] = (w1 >> 8) & 0xff; |
| 192 | out[4] = w2 & 0xff; |
| 193 | out[5] = (w2 >> 8) & 0xff; |
| 194 | out[6] = w3 & 0xff; |
| 195 | out[7] = (w3 >> 8) & 0xff; |
| 196 | } |
| 197 | |
| 198 | void |
| 199 | RC2_cbc_encrypt(const unsigned char *in, unsigned char *out, long size, |
| 200 | RC2_KEY *key, unsigned char *iv, int forward_encrypt) |
| 201 | { |
| 202 | unsigned char tmp[RC2_BLOCK_SIZE]; |
| 203 | int i; |
| 204 | |
| 205 | if (forward_encrypt) { |
| 206 | while (size >= RC2_BLOCK_SIZE) { |
| 207 | for (i = 0; i < RC2_BLOCK_SIZE; i++) |
| 208 | tmp[i] = in[i] ^ iv[i]; |
| 209 | RC2_encryptc(tmp, out, key); |
| 210 | memcpy(iv, out, RC2_BLOCK_SIZE); |
| 211 | size -= RC2_BLOCK_SIZE; |
| 212 | in += RC2_BLOCK_SIZE; |
| 213 | out += RC2_BLOCK_SIZE; |
| 214 | } |
| 215 | if (size) { |
| 216 | for (i = 0; i < size; i++) |
| 217 | tmp[i] = in[i] ^ iv[i]; |
| 218 | for (i = size; i < RC2_BLOCK_SIZE; i++) |
| 219 | tmp[i] = iv[i]; |
| 220 | RC2_encryptc(tmp, out, key); |
| 221 | memcpy(iv, out, RC2_BLOCK_SIZE); |
| 222 | } |
| 223 | } else { |
| 224 | while (size >= RC2_BLOCK_SIZE) { |
| 225 | memcpy(tmp, in, RC2_BLOCK_SIZE); |
| 226 | RC2_decryptc(tmp, out, key); |
| 227 | for (i = 0; i < RC2_BLOCK_SIZE; i++) |
| 228 | out[i] ^= iv[i]; |
| 229 | memcpy(iv, tmp, RC2_BLOCK_SIZE); |
| 230 | size -= RC2_BLOCK_SIZE; |
| 231 | in += RC2_BLOCK_SIZE; |
| 232 | out += RC2_BLOCK_SIZE; |
| 233 | } |
| 234 | if (size) { |
| 235 | memcpy(tmp, in, RC2_BLOCK_SIZE); |
| 236 | RC2_decryptc(tmp, out, key); |
| 237 | for (i = 0; i < size; i++) |
| 238 | out[i] ^= iv[i]; |
| 239 | memcpy(iv, tmp, RC2_BLOCK_SIZE); |
| 240 | } |
| 241 | } |
| 242 | } |