| 1 | /* -*-c-*- |
| 2 | * |
| 3 | * $Id: rc2.c,v 1.1 2000/06/17 11:54:34 mdw Exp $ |
| 4 | * |
| 5 | * The RC2 block cipher |
| 6 | * |
| 7 | * (c) 2000 Straylight/Edgeware |
| 8 | */ |
| 9 | |
| 10 | /*----- Licensing notice --------------------------------------------------* |
| 11 | * |
| 12 | * This file is part of Catacomb. |
| 13 | * |
| 14 | * Catacomb is free software; you can redistribute it and/or modify |
| 15 | * it under the terms of the GNU Library General Public License as |
| 16 | * published by the Free Software Foundation; either version 2 of the |
| 17 | * License, or (at your option) any later version. |
| 18 | * |
| 19 | * Catacomb is distributed in the hope that it will be useful, |
| 20 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 21 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 22 | * GNU Library General Public License for more details. |
| 23 | * |
| 24 | * You should have received a copy of the GNU Library General Public |
| 25 | * License along with Catacomb; if not, write to the Free |
| 26 | * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, |
| 27 | * MA 02111-1307, USA. |
| 28 | */ |
| 29 | |
| 30 | /*----- Revision history --------------------------------------------------* |
| 31 | * |
| 32 | * $Log: rc2.c,v $ |
| 33 | * Revision 1.1 2000/06/17 11:54:34 mdw |
| 34 | * New cipher. |
| 35 | * |
| 36 | */ |
| 37 | |
| 38 | /*----- Header files ------------------------------------------------------*/ |
| 39 | |
| 40 | #include <assert.h> |
| 41 | #include <stdio.h> |
| 42 | |
| 43 | #include <mLib/bits.h> |
| 44 | |
| 45 | #include "blkc.h" |
| 46 | #include "gcipher.h" |
| 47 | #include "paranoia.h" |
| 48 | #include "rc2.h" |
| 49 | |
| 50 | /*----- Global variables --------------------------------------------------*/ |
| 51 | |
| 52 | const octet rc2_keysz[] = { KSZ_RANGE, RC2_KEYSZ, 1, 128, 1 }; |
| 53 | |
| 54 | /*----- Important tables --------------------------------------------------*/ |
| 55 | |
| 56 | static const octet pi[] = { |
| 57 | 0xd9, 0x78, 0xf9, 0xc4, 0x19, 0xdd, 0xb5, 0xed, |
| 58 | 0x28, 0xe9, 0xfd, 0x79, 0x4a, 0xa0, 0xd8, 0x9d, |
| 59 | 0xc6, 0x7e, 0x37, 0x83, 0x2b, 0x76, 0x53, 0x8e, |
| 60 | 0x62, 0x4c, 0x64, 0x88, 0x44, 0x8b, 0xfb, 0xa2, |
| 61 | 0x17, 0x9a, 0x59, 0xf5, 0x87, 0xb3, 0x4f, 0x13, |
| 62 | 0x61, 0x45, 0x6d, 0x8d, 0x09, 0x81, 0x7d, 0x32, |
| 63 | 0xbd, 0x8f, 0x40, 0xeb, 0x86, 0xb7, 0x7b, 0x0b, |
| 64 | 0xf0, 0x95, 0x21, 0x22, 0x5c, 0x6b, 0x4e, 0x82, |
| 65 | 0x54, 0xd6, 0x65, 0x93, 0xce, 0x60, 0xb2, 0x1c, |
| 66 | 0x73, 0x56, 0xc0, 0x14, 0xa7, 0x8c, 0xf1, 0xdc, |
| 67 | 0x12, 0x75, 0xca, 0x1f, 0x3b, 0xbe, 0xe4, 0xd1, |
| 68 | 0x42, 0x3d, 0xd4, 0x30, 0xa3, 0x3c, 0xb6, 0x26, |
| 69 | 0x6f, 0xbf, 0x0e, 0xda, 0x46, 0x69, 0x07, 0x57, |
| 70 | 0x27, 0xf2, 0x1d, 0x9b, 0xbc, 0x94, 0x43, 0x03, |
| 71 | 0xf8, 0x11, 0xc7, 0xf6, 0x90, 0xef, 0x3e, 0xe7, |
| 72 | 0x06, 0xc3, 0xd5, 0x2f, 0xc8, 0x66, 0x1e, 0xd7, |
| 73 | 0x08, 0xe8, 0xea, 0xde, 0x80, 0x52, 0xee, 0xf7, |
| 74 | 0x84, 0xaa, 0x72, 0xac, 0x35, 0x4d, 0x6a, 0x2a, |
| 75 | 0x96, 0x1a, 0xd2, 0x71, 0x5a, 0x15, 0x49, 0x74, |
| 76 | 0x4b, 0x9f, 0xd0, 0x5e, 0x04, 0x18, 0xa4, 0xec, |
| 77 | 0xc2, 0xe0, 0x41, 0x6e, 0x0f, 0x51, 0xcb, 0xcc, |
| 78 | 0x24, 0x91, 0xaf, 0x50, 0xa1, 0xf4, 0x70, 0x39, |
| 79 | 0x99, 0x7c, 0x3a, 0x85, 0x23, 0xb8, 0xb4, 0x7a, |
| 80 | 0xfc, 0x02, 0x36, 0x5b, 0x25, 0x55, 0x97, 0x31, |
| 81 | 0x2d, 0x5d, 0xfa, 0x98, 0xe3, 0x8a, 0x92, 0xae, |
| 82 | 0x05, 0xdf, 0x29, 0x10, 0x67, 0x6c, 0xba, 0xc9, |
| 83 | 0xd3, 0x00, 0xe6, 0xcf, 0xe1, 0x9e, 0xa8, 0x2c, |
| 84 | 0x63, 0x16, 0x01, 0x3f, 0x58, 0xe2, 0x89, 0xa9, |
| 85 | 0x0d, 0x38, 0x34, 0x1b, 0xab, 0x33, 0xff, 0xb0, |
| 86 | 0xbb, 0x48, 0x0c, 0x5f, 0xb9, 0xb1, 0xcd, 0x2e, |
| 87 | 0xc5, 0xf3, 0xdb, 0x47, 0xe5, 0xa5, 0x9c, 0x77, |
| 88 | 0x0a, 0xa6, 0x20, 0x68, 0xfe, 0x7f, 0xc1, 0xad |
| 89 | }; |
| 90 | |
| 91 | /*----- Main code ---------------------------------------------------------*/ |
| 92 | |
| 93 | /* --- @rc2_braindamage@ --- * |
| 94 | * |
| 95 | * Arguments: @rc2_ctx *k@ = pointer to context to initialize |
| 96 | * @const void *buf@ = pointer to key material |
| 97 | * @size_t sz@ = size of key material in bytes |
| 98 | * @unsigned eb@ = desired effective key size, in bits |
| 99 | * |
| 100 | * Returns: --- |
| 101 | * |
| 102 | * Use: Initializes an RC2 expanded key, and braindamages it to the |
| 103 | * requested effective key size. This is here for compatibility |
| 104 | * reasons. You should be using @rc2_init@ in normal code, |
| 105 | * which doesn't actually apply braindamage. |
| 106 | */ |
| 107 | |
| 108 | void rc2_braindamage(rc2_ctx *k, const void *buf, size_t sz, unsigned eb) |
| 109 | { |
| 110 | unsigned t8; |
| 111 | uint16 tm; |
| 112 | unsigned i; |
| 113 | uint16 *kk; |
| 114 | octet l[128]; |
| 115 | |
| 116 | KSZ_ASSERT(rc2, sz); |
| 117 | |
| 118 | /* --- Compute the braindamage parameters --- */ |
| 119 | |
| 120 | t8 = (eb + 7) / 8; |
| 121 | tm = 0xff & ((1 << (8 + eb - 8 * t8)) - 1); |
| 122 | |
| 123 | /* --- Copy and expand the initial key --- */ |
| 124 | |
| 125 | if (sz > sizeof(l)) |
| 126 | sz = sizeof(l); |
| 127 | memcpy(l, buf, sz); |
| 128 | |
| 129 | for (i = sz; i < sizeof(l); i++) |
| 130 | l[i] = pi[U8(l[i - 1] + l[i - sz])]; |
| 131 | |
| 132 | /* --- Braindamage the key --- */ |
| 133 | |
| 134 | i = sizeof(l) - t8; |
| 135 | l[i] = pi[l[i] & tm]; |
| 136 | while (i) { |
| 137 | i--; |
| 138 | l[i] = pi[U8(l[i + 1] ^ l[i + t8])]; |
| 139 | } |
| 140 | |
| 141 | /* --- Write it to the key block --- */ |
| 142 | |
| 143 | kk = k->k; |
| 144 | for (i = 0; i < sizeof(l); i += 2) |
| 145 | *kk++ = LOAD16_L(l + i); |
| 146 | BURN(l); |
| 147 | } |
| 148 | |
| 149 | /* --- @rc2_init@ --- * |
| 150 | * |
| 151 | * Arguments: @rc2_ctx *k@ = pointer to context to initialize |
| 152 | * @const void *buf@ = pointer to key material |
| 153 | * @size_t sz@ = size of key material in bytes |
| 154 | * |
| 155 | * Returns: --- |
| 156 | * |
| 157 | * Use: Initializes an RC2 expanded key. The effective key size is |
| 158 | * set to be equal to the real key size, in bits. |
| 159 | */ |
| 160 | |
| 161 | void rc2_init(rc2_ctx *k, const void *buf, size_t sz) |
| 162 | { |
| 163 | rc2_braindamage(k, buf, sz, sz * 8); |
| 164 | } |
| 165 | |
| 166 | /*----- Encryption and decryption -----------------------------------------*/ |
| 167 | |
| 168 | #define MIX(a, b, c, d, r, kk) do { \ |
| 169 | a += *kk++ + (d & c) + (~d & b); \ |
| 170 | a = ROL16(a, r); \ |
| 171 | } while (0) |
| 172 | |
| 173 | #define MASH(a, d, k) do { \ |
| 174 | a += k[d & 63]; \ |
| 175 | } while (0) |
| 176 | |
| 177 | #define UNMIX(a, b, c, d, r, kk) do { \ |
| 178 | a = ROR16(a, r); \ |
| 179 | a -= *--kk + (d & c) + (~d & b); \ |
| 180 | } while (0) |
| 181 | |
| 182 | #define UNMASH(a, d, k) do { \ |
| 183 | a -= k[d & 63]; \ |
| 184 | } while (0) |
| 185 | |
| 186 | /* --- @rc2_eblk@, @rc2_dblk@ --- * |
| 187 | * |
| 188 | * Arguments: @const rc2_ctx *k@ = pointer to RC2 context |
| 189 | * @const uint32 s[2]@ = pointer to source block |
| 190 | * @const uint32 d[2]@ = pointer to destination block |
| 191 | * |
| 192 | * Returns: --- |
| 193 | * |
| 194 | * Use: Low-level block encryption and decryption. |
| 195 | */ |
| 196 | |
| 197 | void rc2_eblk(const rc2_ctx *k, const uint32 *s, uint32 *dst) |
| 198 | { |
| 199 | uint16 a = U16(s[0] >> 0), b = U16(s[0] >> 16); |
| 200 | uint16 c = U16(s[1] >> 0), d = U16(s[1] >> 16); |
| 201 | const uint16 *kk = k->k; |
| 202 | |
| 203 | MIX(a, b, c, d, 1, kk); MIX(b, c, d, a, 2, kk); |
| 204 | MIX(c, d, a, b, 3, kk); MIX(d, a, b, c, 5, kk); |
| 205 | MIX(a, b, c, d, 1, kk); MIX(b, c, d, a, 2, kk); |
| 206 | MIX(c, d, a, b, 3, kk); MIX(d, a, b, c, 5, kk); |
| 207 | MIX(a, b, c, d, 1, kk); MIX(b, c, d, a, 2, kk); |
| 208 | MIX(c, d, a, b, 3, kk); MIX(d, a, b, c, 5, kk); |
| 209 | MIX(a, b, c, d, 1, kk); MIX(b, c, d, a, 2, kk); |
| 210 | MIX(c, d, a, b, 3, kk); MIX(d, a, b, c, 5, kk); |
| 211 | MIX(a, b, c, d, 1, kk); MIX(b, c, d, a, 2, kk); |
| 212 | MIX(c, d, a, b, 3, kk); MIX(d, a, b, c, 5, kk); |
| 213 | MASH(a, d, k->k); MASH(b, a, k->k); |
| 214 | MASH(c, b, k->k); MASH(d, c, k->k); |
| 215 | MIX(a, b, c, d, 1, kk); MIX(b, c, d, a, 2, kk); |
| 216 | MIX(c, d, a, b, 3, kk); MIX(d, a, b, c, 5, kk); |
| 217 | MIX(a, b, c, d, 1, kk); MIX(b, c, d, a, 2, kk); |
| 218 | MIX(c, d, a, b, 3, kk); MIX(d, a, b, c, 5, kk); |
| 219 | MIX(a, b, c, d, 1, kk); MIX(b, c, d, a, 2, kk); |
| 220 | MIX(c, d, a, b, 3, kk); MIX(d, a, b, c, 5, kk); |
| 221 | MIX(a, b, c, d, 1, kk); MIX(b, c, d, a, 2, kk); |
| 222 | MIX(c, d, a, b, 3, kk); MIX(d, a, b, c, 5, kk); |
| 223 | MIX(a, b, c, d, 1, kk); MIX(b, c, d, a, 2, kk); |
| 224 | MIX(c, d, a, b, 3, kk); MIX(d, a, b, c, 5, kk); |
| 225 | MIX(a, b, c, d, 1, kk); MIX(b, c, d, a, 2, kk); |
| 226 | MIX(c, d, a, b, 3, kk); MIX(d, a, b, c, 5, kk); |
| 227 | MASH(a, d, k->k); MASH(b, a, k->k); |
| 228 | MASH(c, b, k->k); MASH(d, c, k->k); |
| 229 | MIX(a, b, c, d, 1, kk); MIX(b, c, d, a, 2, kk); |
| 230 | MIX(c, d, a, b, 3, kk); MIX(d, a, b, c, 5, kk); |
| 231 | MIX(a, b, c, d, 1, kk); MIX(b, c, d, a, 2, kk); |
| 232 | MIX(c, d, a, b, 3, kk); MIX(d, a, b, c, 5, kk); |
| 233 | MIX(a, b, c, d, 1, kk); MIX(b, c, d, a, 2, kk); |
| 234 | MIX(c, d, a, b, 3, kk); MIX(d, a, b, c, 5, kk); |
| 235 | MIX(a, b, c, d, 1, kk); MIX(b, c, d, a, 2, kk); |
| 236 | MIX(c, d, a, b, 3, kk); MIX(d, a, b, c, 5, kk); |
| 237 | MIX(a, b, c, d, 1, kk); MIX(b, c, d, a, 2, kk); |
| 238 | MIX(c, d, a, b, 3, kk); MIX(d, a, b, c, 5, kk); |
| 239 | |
| 240 | dst[0] = a | (b << 16); dst[1] = c | (d << 16); |
| 241 | } |
| 242 | |
| 243 | void rc2_dblk(const rc2_ctx *k, const uint32 *s, uint32 *dst) |
| 244 | { |
| 245 | uint16 a = U16(s[0] >> 0), b = U16(s[0] >> 16); |
| 246 | uint16 c = U16(s[1] >> 0), d = U16(s[1] >> 16); |
| 247 | const uint16 *kk = k->k + 64; |
| 248 | |
| 249 | UNMIX(d, a, b, c, 5, kk); UNMIX(c, d, a, b, 3, kk); |
| 250 | UNMIX(b, c, d, a, 2, kk); UNMIX(a, b, c, d, 1, kk); |
| 251 | UNMIX(d, a, b, c, 5, kk); UNMIX(c, d, a, b, 3, kk); |
| 252 | UNMIX(b, c, d, a, 2, kk); UNMIX(a, b, c, d, 1, kk); |
| 253 | UNMIX(d, a, b, c, 5, kk); UNMIX(c, d, a, b, 3, kk); |
| 254 | UNMIX(b, c, d, a, 2, kk); UNMIX(a, b, c, d, 1, kk); |
| 255 | UNMIX(d, a, b, c, 5, kk); UNMIX(c, d, a, b, 3, kk); |
| 256 | UNMIX(b, c, d, a, 2, kk); UNMIX(a, b, c, d, 1, kk); |
| 257 | UNMIX(d, a, b, c, 5, kk); UNMIX(c, d, a, b, 3, kk); |
| 258 | UNMIX(b, c, d, a, 2, kk); UNMIX(a, b, c, d, 1, kk); |
| 259 | UNMASH(d, c, k->k); UNMASH(c, b, k->k); |
| 260 | UNMASH(b, a, k->k); UNMASH(a, d, k->k); |
| 261 | UNMIX(d, a, b, c, 5, kk); UNMIX(c, d, a, b, 3, kk); |
| 262 | UNMIX(b, c, d, a, 2, kk); UNMIX(a, b, c, d, 1, kk); |
| 263 | UNMIX(d, a, b, c, 5, kk); UNMIX(c, d, a, b, 3, kk); |
| 264 | UNMIX(b, c, d, a, 2, kk); UNMIX(a, b, c, d, 1, kk); |
| 265 | UNMIX(d, a, b, c, 5, kk); UNMIX(c, d, a, b, 3, kk); |
| 266 | UNMIX(b, c, d, a, 2, kk); UNMIX(a, b, c, d, 1, kk); |
| 267 | UNMIX(d, a, b, c, 5, kk); UNMIX(c, d, a, b, 3, kk); |
| 268 | UNMIX(b, c, d, a, 2, kk); UNMIX(a, b, c, d, 1, kk); |
| 269 | UNMIX(d, a, b, c, 5, kk); UNMIX(c, d, a, b, 3, kk); |
| 270 | UNMIX(b, c, d, a, 2, kk); UNMIX(a, b, c, d, 1, kk); |
| 271 | UNMIX(d, a, b, c, 5, kk); UNMIX(c, d, a, b, 3, kk); |
| 272 | UNMIX(b, c, d, a, 2, kk); UNMIX(a, b, c, d, 1, kk); |
| 273 | UNMASH(d, c, k->k); UNMASH(c, b, k->k); |
| 274 | UNMASH(b, a, k->k); UNMASH(a, d, k->k); |
| 275 | UNMIX(d, a, b, c, 5, kk); UNMIX(c, d, a, b, 3, kk); |
| 276 | UNMIX(b, c, d, a, 2, kk); UNMIX(a, b, c, d, 1, kk); |
| 277 | UNMIX(d, a, b, c, 5, kk); UNMIX(c, d, a, b, 3, kk); |
| 278 | UNMIX(b, c, d, a, 2, kk); UNMIX(a, b, c, d, 1, kk); |
| 279 | UNMIX(d, a, b, c, 5, kk); UNMIX(c, d, a, b, 3, kk); |
| 280 | UNMIX(b, c, d, a, 2, kk); UNMIX(a, b, c, d, 1, kk); |
| 281 | UNMIX(d, a, b, c, 5, kk); UNMIX(c, d, a, b, 3, kk); |
| 282 | UNMIX(b, c, d, a, 2, kk); UNMIX(a, b, c, d, 1, kk); |
| 283 | UNMIX(d, a, b, c, 5, kk); UNMIX(c, d, a, b, 3, kk); |
| 284 | UNMIX(b, c, d, a, 2, kk); UNMIX(a, b, c, d, 1, kk); |
| 285 | |
| 286 | dst[0] = a | (b << 16); dst[1] = c | (d << 16); |
| 287 | } |
| 288 | |
| 289 | /*----- Custom test rig ---------------------------------------------------* |
| 290 | * |
| 291 | * I need to test the braindamage feature. |
| 292 | */ |
| 293 | |
| 294 | #ifdef TEST_RIG |
| 295 | |
| 296 | #include <mLib/quis.h> |
| 297 | #include <mLib/testrig.h> |
| 298 | |
| 299 | static int verify(dstr *v) |
| 300 | { |
| 301 | rc2_ctx k; |
| 302 | uint32 p[RC2_BLKSZ / 4]; |
| 303 | uint32 c[RC2_BLKSZ / 4]; |
| 304 | uint32 d[RC2_BLKSZ / 4]; |
| 305 | dstr b = DSTR_INIT; |
| 306 | unsigned bd = *(unsigned *)v[1].buf; |
| 307 | int ok = 1; |
| 308 | |
| 309 | /* --- Initialize the key buffer --- */ |
| 310 | |
| 311 | dstr_ensure(&b, RC2_BLKSZ); |
| 312 | b.len = RC2_BLKSZ; |
| 313 | rc2_braindamage(&k, v[0].buf, v[0].len, bd); |
| 314 | BLKC_LOAD(RC2, p, v[2].buf); |
| 315 | BLKC_LOAD(RC2, c, v[3].buf); |
| 316 | |
| 317 | /* --- Test encryption --- */ |
| 318 | |
| 319 | BLKC_MOVE(RC2, d, p); |
| 320 | rc2_eblk(&k, d, d); |
| 321 | BLKC_STORE(RC2, b.buf, d); |
| 322 | if (memcmp(b.buf, v[3].buf, RC2_BLKSZ)) { |
| 323 | ok = 0; |
| 324 | printf("\nfail encryption:" |
| 325 | "\n\tkey = "); |
| 326 | type_hex.dump(&v[0], stdout); |
| 327 | printf("\n\tbraindamage= %u", bd); |
| 328 | printf("\n\tplaintext = "); type_hex.dump(&v[2], stdout); |
| 329 | printf("\n\texpected = "); type_hex.dump(&v[3], stdout); |
| 330 | printf("\n\tcalculated = "); type_hex.dump(&b, stdout); |
| 331 | putchar('\n'); |
| 332 | } |
| 333 | |
| 334 | /* --- Test decryption --- */ |
| 335 | |
| 336 | BLKC_MOVE(RC2, d, c); |
| 337 | rc2_dblk(&k, d, d); |
| 338 | BLKC_STORE(RC2, b.buf, d); |
| 339 | if (memcmp(b.buf, v[2].buf, RC2_BLKSZ)) { |
| 340 | ok = 0; |
| 341 | printf("\nfail decryption:" |
| 342 | "\n\tkey = "); |
| 343 | type_hex.dump(&v[0], stdout); |
| 344 | printf("\n\tbraindamage= %u", bd); |
| 345 | printf("\n\tciphertext = "); type_hex.dump(&v[3], stdout); |
| 346 | printf("\n\texpected = "); type_hex.dump(&v[2], stdout); |
| 347 | printf("\n\tcalculated = "); type_hex.dump(&b, stdout); |
| 348 | putchar('\n'); |
| 349 | } |
| 350 | |
| 351 | /* --- Return --- */ |
| 352 | |
| 353 | return (ok); |
| 354 | } |
| 355 | |
| 356 | static test_chunk defs[] = { |
| 357 | { "rc2", verify, { &type_hex, &type_int, &type_hex, &type_hex, 0 } }, |
| 358 | { 0, 0, { 0 } } |
| 359 | }; |
| 360 | |
| 361 | int main(int argc, char *argv[]) |
| 362 | { |
| 363 | test_run(argc, argv, defs, SRCDIR"/tests/rc2"); |
| 364 | return (0); |
| 365 | } |
| 366 | |
| 367 | #endif |
| 368 | |
| 369 | /*----- That's all, folks -------------------------------------------------*/ |