| 1 | /* crapto1.c\r |
| 2 | \r |
| 3 | This program is free software; you can redistribute it and/or\r |
| 4 | modify it under the terms of the GNU General Public License\r |
| 5 | as published by the Free Software Foundation; either version 2\r |
| 6 | of the License, or (at your option) any later version.\r |
| 7 | \r |
| 8 | This program is distributed in the hope that it will be useful,\r |
| 9 | but WITHOUT ANY WARRANTY; without even the implied warranty of\r |
| 10 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the\r |
| 11 | GNU General Public License for more details.\r |
| 12 | \r |
| 13 | You should have received a copy of the GNU General Public License\r |
| 14 | along with this program; if not, write to the Free Software\r |
| 15 | Foundation, Inc., 51 Franklin Street, Fifth Floor,\r |
| 16 | Boston, MA 02110-1301, US$\r |
| 17 | \r |
| 18 | Copyright (C) 2008-2008 bla <blapost@gmail.com>\r |
| 19 | */\r |
| 20 | #include "crapto1.h"\r |
| 21 | #include <stdlib.h>\r |
| 22 | \r |
| 23 | #if !defined LOWMEM && defined __GNUC__\r |
| 24 | static uint8_t filterlut[1 << 20];\r |
| 25 | static void __attribute__((constructor)) fill_lut()\r |
| 26 | {\r |
| 27 | uint32_t i;\r |
| 28 | for(i = 0; i < 1 << 20; ++i)\r |
| 29 | filterlut[i] = filter(i);\r |
| 30 | }\r |
| 31 | #define filter(x) (filterlut[(x) & 0xfffff])\r |
| 32 | #endif\r |
| 33 | \r |
| 34 | static void quicksort(uint32_t* const start, uint32_t* const stop)\r |
| 35 | {\r |
| 36 | uint32_t *it = start + 1, *rit = stop;\r |
| 37 | \r |
| 38 | if(it > rit)\r |
| 39 | return;\r |
| 40 | \r |
| 41 | while(it < rit)\r |
| 42 | if(*it <= *start)\r |
| 43 | ++it;\r |
| 44 | else if(*rit > *start)\r |
| 45 | --rit;\r |
| 46 | else\r |
| 47 | *it ^= (*it ^= *rit, *rit ^= *it);\r |
| 48 | \r |
| 49 | if(*rit >= *start)\r |
| 50 | --rit;\r |
| 51 | if(rit != start)\r |
| 52 | *rit ^= (*rit ^= *start, *start ^= *rit);\r |
| 53 | \r |
| 54 | quicksort(start, rit - 1);\r |
| 55 | quicksort(rit + 1, stop);\r |
| 56 | }\r |
| 57 | /** binsearch\r |
| 58 | * Binary search for the first occurence of *stop's MSB in sorted [start,stop]\r |
| 59 | */\r |
| 60 | static inline uint32_t* binsearch(uint32_t *start, uint32_t *stop)\r |
| 61 | {\r |
| 62 | uint32_t mid, val = *stop & 0xff000000;\r |
| 63 | while(start != stop)\r |
| 64 | if(start[mid = (stop - start) >> 1] > val)\r |
| 65 | stop = &start[mid];\r |
| 66 | else\r |
| 67 | start += mid + 1;\r |
| 68 | \r |
| 69 | return start;\r |
| 70 | }\r |
| 71 | \r |
| 72 | /** update_contribution\r |
| 73 | * helper, calculates the partial linear feedback contributions and puts in MSB\r |
| 74 | */\r |
| 75 | static inline void\r |
| 76 | update_contribution(uint32_t *item, const uint32_t mask1, const uint32_t mask2)\r |
| 77 | {\r |
| 78 | uint32_t p = *item >> 25;\r |
| 79 | \r |
| 80 | p = p << 1 | parity(*item & mask1);\r |
| 81 | p = p << 1 | parity(*item & mask2);\r |
| 82 | *item = p << 24 | (*item & 0xffffff);\r |
| 83 | }\r |
| 84 | \r |
| 85 | /** extend_table\r |
| 86 | * using a bit of the keystream extend the table of possible lfsr states\r |
| 87 | */\r |
| 88 | static inline void\r |
| 89 | extend_table(uint32_t *tbl, uint32_t **end, int bit, int m1, int m2, uint32_t in)\r |
| 90 | {\r |
| 91 | in <<= 24;\r |
| 92 | for(*tbl <<= 1; tbl <= *end; *++tbl <<= 1)\r |
| 93 | if(filter(*tbl) ^ filter(*tbl | 1)) {\r |
| 94 | *tbl |= filter(*tbl) ^ bit;\r |
| 95 | update_contribution(tbl, m1, m2);\r |
| 96 | *tbl ^= in;\r |
| 97 | } else if(filter(*tbl) == bit) {\r |
| 98 | *++*end = tbl[1];\r |
| 99 | tbl[1] = tbl[0] | 1;\r |
| 100 | update_contribution(tbl, m1, m2);\r |
| 101 | *tbl++ ^= in;\r |
| 102 | update_contribution(tbl, m1, m2);\r |
| 103 | *tbl ^= in;\r |
| 104 | } else\r |
| 105 | *tbl-- = *(*end)--;\r |
| 106 | }\r |
| 107 | /** extend_table_simple\r |
| 108 | * using a bit of the keystream extend the table of possible lfsr states\r |
| 109 | */\r |
| 110 | static inline void extend_table_simple(uint32_t *tbl, uint32_t **end, int bit)\r |
| 111 | {\r |
| 112 | for(*tbl <<= 1; tbl <= *end; *++tbl <<= 1)\r |
| 113 | if(filter(*tbl) ^ filter(*tbl | 1))\r |
| 114 | *tbl |= filter(*tbl) ^ bit;\r |
| 115 | else if(filter(*tbl) == bit) {\r |
| 116 | *++*end = *++tbl;\r |
| 117 | *tbl = tbl[-1] | 1;\r |
| 118 | } else\r |
| 119 | *tbl-- = *(*end)--;\r |
| 120 | }\r |
| 121 | /** recover\r |
| 122 | * recursively narrow down the search space, 4 bits of keystream at a time\r |
| 123 | */\r |
| 124 | static struct Crypto1State*\r |
| 125 | recover(uint32_t *o_head, uint32_t *o_tail, uint32_t oks,\r |
| 126 | uint32_t *e_head, uint32_t *e_tail, uint32_t eks, int rem,\r |
| 127 | struct Crypto1State *sl, uint32_t in)\r |
| 128 | {\r |
| 129 | uint32_t *o, *e, i;\r |
| 130 | \r |
| 131 | if(rem == -1) {\r |
| 132 | for(e = e_head; e <= e_tail; ++e) {\r |
| 133 | *e = *e << 1 ^ parity(*e & LF_POLY_EVEN) ^ !!(in & 4);\r |
| 134 | for(o = o_head; o <= o_tail; ++o, ++sl) {\r |
| 135 | sl->even = *o;\r |
| 136 | sl->odd = *e ^ parity(*o & LF_POLY_ODD);\r |
| 137 | sl[1].odd = sl[1].even = 0;\r |
| 138 | }\r |
| 139 | }\r |
| 140 | return sl;\r |
| 141 | }\r |
| 142 | \r |
| 143 | for(i = 0; i < 4 && rem--; i++) {\r |
| 144 | oks >>= 1;\r |
| 145 | eks >>= 1;\r |
| 146 | in >>= 2;\r |
| 147 | extend_table(o_head, &o_tail, oks & 1, LF_POLY_EVEN << 1 | 1,\r |
| 148 | LF_POLY_ODD << 1, 0);\r |
| 149 | if(o_head > o_tail)\r |
| 150 | return sl;\r |
| 151 | \r |
| 152 | extend_table(e_head, &e_tail, eks & 1, LF_POLY_ODD,\r |
| 153 | LF_POLY_EVEN << 1 | 1, in & 3);\r |
| 154 | if(e_head > e_tail)\r |
| 155 | return sl;\r |
| 156 | }\r |
| 157 | \r |
| 158 | quicksort(o_head, o_tail);\r |
| 159 | quicksort(e_head, e_tail);\r |
| 160 | \r |
| 161 | while(o_tail >= o_head && e_tail >= e_head)\r |
| 162 | if(((*o_tail ^ *e_tail) >> 24) == 0) {\r |
| 163 | o_tail = binsearch(o_head, o = o_tail);\r |
| 164 | e_tail = binsearch(e_head, e = e_tail);\r |
| 165 | sl = recover(o_tail--, o, oks,\r |
| 166 | e_tail--, e, eks, rem, sl, in);\r |
| 167 | }\r |
| 168 | else if(*o_tail > *e_tail)\r |
| 169 | o_tail = binsearch(o_head, o_tail) - 1;\r |
| 170 | else\r |
| 171 | e_tail = binsearch(e_head, e_tail) - 1;\r |
| 172 | \r |
| 173 | return sl;\r |
| 174 | }\r |
| 175 | /** lfsr_recovery\r |
| 176 | * recover the state of the lfsr given 32 bits of the keystream\r |
| 177 | * additionally you can use the in parameter to specify the value\r |
| 178 | * that was fed into the lfsr at the time the keystream was generated\r |
| 179 | */\r |
| 180 | struct Crypto1State* lfsr_recovery32(uint32_t ks2, uint32_t in)\r |
| 181 | {\r |
| 182 | struct Crypto1State *statelist;\r |
| 183 | uint32_t *odd_head = 0, *odd_tail = 0, oks = 0;\r |
| 184 | uint32_t *even_head = 0, *even_tail = 0, eks = 0;\r |
| 185 | int i;\r |
| 186 | \r |
| 187 | for(i = 31; i >= 0; i -= 2)\r |
| 188 | oks = oks << 1 | BEBIT(ks2, i);\r |
| 189 | for(i = 30; i >= 0; i -= 2)\r |
| 190 | eks = eks << 1 | BEBIT(ks2, i);\r |
| 191 | \r |
| 192 | odd_head = odd_tail = malloc(sizeof(uint32_t) << 21);\r |
| 193 | even_head = even_tail = malloc(sizeof(uint32_t) << 21);\r |
| 194 | statelist = malloc(sizeof(struct Crypto1State) << 18);\r |
| 195 | if(!odd_tail-- || !even_tail-- || !statelist) {\r |
| 196 | free(statelist);\r |
| 197 | statelist = 0;\r |
| 198 | goto out;\r |
| 199 | }\r |
| 200 | \r |
| 201 | statelist->odd = statelist->even = 0;\r |
| 202 | \r |
| 203 | for(i = 1 << 20; i >= 0; --i) {\r |
| 204 | if(filter(i) == (oks & 1))\r |
| 205 | *++odd_tail = i;\r |
| 206 | if(filter(i) == (eks & 1))\r |
| 207 | *++even_tail = i;\r |
| 208 | }\r |
| 209 | \r |
| 210 | for(i = 0; i < 4; i++) {\r |
| 211 | extend_table_simple(odd_head, &odd_tail, (oks >>= 1) & 1);\r |
| 212 | extend_table_simple(even_head, &even_tail, (eks >>= 1) & 1);\r |
| 213 | }\r |
| 214 | \r |
| 215 | in = (in >> 16 & 0xff) | (in << 16) | (in & 0xff00);\r |
| 216 | recover(odd_head, odd_tail, oks,\r |
| 217 | even_head, even_tail, eks, 11, statelist, in << 1);\r |
| 218 | \r |
| 219 | out:\r |
| 220 | free(odd_head);\r |
| 221 | free(even_head);\r |
| 222 | return statelist;\r |
| 223 | }\r |
| 224 | \r |
| 225 | static const uint32_t S1[] = { 0x62141, 0x310A0, 0x18850, 0x0C428, 0x06214,\r |
| 226 | 0x0310A, 0x85E30, 0xC69AD, 0x634D6, 0xB5CDE, 0xDE8DA, 0x6F46D, 0xB3C83,\r |
| 227 | 0x59E41, 0xA8995, 0xD027F, 0x6813F, 0x3409F, 0x9E6FA};\r |
| 228 | static const uint32_t S2[] = { 0x3A557B00, 0x5D2ABD80, 0x2E955EC0, 0x174AAF60,\r |
| 229 | 0x0BA557B0, 0x05D2ABD8, 0x0449DE68, 0x048464B0, 0x42423258, 0x278192A8,\r |
| 230 | 0x156042D0, 0x0AB02168, 0x43F89B30, 0x61FC4D98, 0x765EAD48, 0x7D8FDD20,\r |
| 231 | 0x7EC7EE90, 0x7F63F748, 0x79117020};\r |
| 232 | static const uint32_t T1[] = {\r |
| 233 | 0x4F37D, 0x279BE, 0x97A6A, 0x4BD35, 0x25E9A, 0x12F4D, 0x097A6, 0x80D66,\r |
| 234 | 0xC4006, 0x62003, 0xB56B4, 0x5AB5A, 0xA9318, 0xD0F39, 0x6879C, 0xB057B,\r |
| 235 | 0x582BD, 0x2C15E, 0x160AF, 0x8F6E2, 0xC3DC4, 0xE5857, 0x72C2B, 0x39615,\r |
| 236 | 0x98DBF, 0xC806A, 0xE0680, 0x70340, 0x381A0, 0x98665, 0x4C332, 0xA272C};\r |
| 237 | static const uint32_t T2[] = { 0x3C88B810, 0x5E445C08, 0x2982A580, 0x14C152C0,\r |
| 238 | 0x4A60A960, 0x253054B0, 0x52982A58, 0x2FEC9EA8, 0x1156C4D0, 0x08AB6268,\r |
| 239 | 0x42F53AB0, 0x217A9D58, 0x161DC528, 0x0DAE6910, 0x46D73488, 0x25CB11C0,\r |
| 240 | 0x52E588E0, 0x6972C470, 0x34B96238, 0x5CFC3A98, 0x28DE96C8, 0x12CFC0E0,\r |
| 241 | 0x4967E070, 0x64B3F038, 0x74F97398, 0x7CDC3248, 0x38CE92A0, 0x1C674950,\r |
| 242 | 0x0E33A4A8, 0x01B959D0, 0x40DCACE8, 0x26CEDDF0};\r |
| 243 | static const uint32_t C1[] = { 0x846B5, 0x4235A, 0x211AD};\r |
| 244 | static const uint32_t C2[] = { 0x1A822E0, 0x21A822E0, 0x21A822E0};\r |
| 245 | /** Reverse 64 bits of keystream into possible cipher states\r |
| 246 | * Variation mentioned in the paper. Somewhat optimized version\r |
| 247 | */\r |
| 248 | struct Crypto1State* lfsr_recovery64(uint32_t ks2, uint32_t ks3)\r |
| 249 | {\r |
| 250 | struct Crypto1State *statelist, *sl;\r |
| 251 | uint8_t oks[32], eks[32], hi[32];\r |
| 252 | uint32_t low = 0, win = 0;\r |
| 253 | uint32_t *tail, table[1 << 16];\r |
| 254 | int i, j;\r |
| 255 | \r |
| 256 | sl = statelist = malloc(sizeof(struct Crypto1State) << 4);\r |
| 257 | if(!sl)\r |
| 258 | return 0;\r |
| 259 | sl->odd = sl->even = 0;\r |
| 260 | \r |
| 261 | for(i = 30; i >= 0; i -= 2) {\r |
| 262 | oks[i >> 1] = BEBIT(ks2, i);\r |
| 263 | oks[16 + (i >> 1)] = BEBIT(ks3, i);\r |
| 264 | }\r |
| 265 | for(i = 31; i >= 0; i -= 2) {\r |
| 266 | eks[i >> 1] = BEBIT(ks2, i);\r |
| 267 | eks[16 + (i >> 1)] = BEBIT(ks3, i);\r |
| 268 | }\r |
| 269 | \r |
| 270 | for(i = 0xfffff; i >= 0; --i) {\r |
| 271 | if (filter(i) != oks[0])\r |
| 272 | continue;\r |
| 273 | \r |
| 274 | *(tail = table) = i;\r |
| 275 | for(j = 1; tail >= table && j < 29; ++j)\r |
| 276 | extend_table_simple(table, &tail, oks[j]);\r |
| 277 | \r |
| 278 | if(tail < table)\r |
| 279 | continue;\r |
| 280 | \r |
| 281 | for(j = 0; j < 19; ++j)\r |
| 282 | low = low << 1 | parity(i & S1[j]);\r |
| 283 | for(j = 0; j < 32; ++j)\r |
| 284 | hi[j] = parity(i & T1[j]);\r |
| 285 | \r |
| 286 | for(; tail >= table; --tail) {\r |
| 287 | for(j = 0; j < 3; ++j) {\r |
| 288 | *tail = *tail << 1;\r |
| 289 | *tail |= parity((i & C1[j]) ^ (*tail & C2[j]));\r |
| 290 | if(filter(*tail) != oks[29 + j])\r |
| 291 | goto continue2;\r |
| 292 | }\r |
| 293 | \r |
| 294 | for(j = 0; j < 19; ++j)\r |
| 295 | win = win << 1 | parity(*tail & S2[j]);\r |
| 296 | \r |
| 297 | win ^= low;\r |
| 298 | for(j = 0; j < 32; ++j) {\r |
| 299 | win = win << 1 ^ hi[j] ^ parity(*tail & T2[j]);\r |
| 300 | if(filter(win) != eks[j])\r |
| 301 | goto continue2;\r |
| 302 | }\r |
| 303 | \r |
| 304 | *tail = *tail << 1 | parity(LF_POLY_EVEN & *tail);\r |
| 305 | sl->odd = *tail ^ parity(LF_POLY_ODD & win);\r |
| 306 | sl->even = win;\r |
| 307 | ++sl;\r |
| 308 | sl->odd = sl->even = 0;\r |
| 309 | continue2:;\r |
| 310 | }\r |
| 311 | }\r |
| 312 | return statelist;\r |
| 313 | }\r |
| 314 | \r |
| 315 | /** lfsr_rollback_bit\r |
| 316 | * Rollback the shift register in order to get previous states\r |
| 317 | */\r |
| 318 | uint8_t lfsr_rollback_bit(struct Crypto1State *s, uint32_t in, int fb)\r |
| 319 | {\r |
| 320 | int out;\r |
| 321 | uint8_t ret;\r |
| 322 | \r |
| 323 | s->odd &= 0xffffff;\r |
| 324 | s->odd ^= (s->odd ^= s->even, s->even ^= s->odd);\r |
| 325 | \r |
| 326 | out = s->even & 1;\r |
| 327 | out ^= LF_POLY_EVEN & (s->even >>= 1);\r |
| 328 | out ^= LF_POLY_ODD & s->odd;\r |
| 329 | out ^= !!in;\r |
| 330 | out ^= (ret = filter(s->odd)) & !!fb;\r |
| 331 | \r |
| 332 | s->even |= parity(out) << 23;\r |
| 333 | return ret;\r |
| 334 | }\r |
| 335 | /** lfsr_rollback_byte\r |
| 336 | * Rollback the shift register in order to get previous states\r |
| 337 | */\r |
| 338 | uint8_t lfsr_rollback_byte(struct Crypto1State *s, uint32_t in, int fb)\r |
| 339 | {\r |
| 340 | int i, ret = 0;\r |
| 341 | for (i = 7; i >= 0; --i)\r |
| 342 | ret |= lfsr_rollback_bit(s, BIT(in, i), fb) << i;\r |
| 343 | return ret;\r |
| 344 | }\r |
| 345 | /** lfsr_rollback_word\r |
| 346 | * Rollback the shift register in order to get previous states\r |
| 347 | */\r |
| 348 | uint32_t lfsr_rollback_word(struct Crypto1State *s, uint32_t in, int fb)\r |
| 349 | {\r |
| 350 | int i;\r |
| 351 | uint32_t ret = 0;\r |
| 352 | for (i = 31; i >= 0; --i)\r |
| 353 | ret |= lfsr_rollback_bit(s, BEBIT(in, i), fb) << (i ^ 24);\r |
| 354 | return ret;\r |
| 355 | }\r |
| 356 | \r |
| 357 | /** nonce_distance\r |
| 358 | * x,y valid tag nonces, then prng_successor(x, nonce_distance(x, y)) = y\r |
| 359 | */\r |
| 360 | static uint16_t *dist = 0;\r |
| 361 | int nonce_distance(uint32_t from, uint32_t to)\r |
| 362 | {\r |
| 363 | uint16_t x, i;\r |
| 364 | if(!dist) {\r |
| 365 | dist = malloc(2 << 16);\r |
| 366 | if(!dist)\r |
| 367 | return -1;\r |
| 368 | for (x = i = 1; i; ++i) {\r |
| 369 | dist[(x & 0xff) << 8 | x >> 8] = i;\r |
| 370 | x = x >> 1 | (x ^ x >> 2 ^ x >> 3 ^ x >> 5) << 15;\r |
| 371 | }\r |
| 372 | }\r |
| 373 | return (65535 + dist[to >> 16] - dist[from >> 16]) % 65535;\r |
| 374 | }\r |
| 375 | \r |
| 376 | \r |
| 377 | static uint32_t fastfwd[2][8] = {\r |
| 378 | { 0, 0x4BC53, 0xECB1, 0x450E2, 0x25E29, 0x6E27A, 0x2B298, 0x60ECB},\r |
| 379 | { 0, 0x1D962, 0x4BC53, 0x56531, 0xECB1, 0x135D3, 0x450E2, 0x58980}};\r |
| 380 | /** lfsr_prefix_ks\r |
| 381 | *\r |
| 382 | * Is an exported helper function from the common prefix attack\r |
| 383 | * Described in the "dark side" paper. It returns an -1 terminated array\r |
| 384 | * of possible partial(21 bit) secret state.\r |
| 385 | * The required keystream(ks) needs to contain the keystream that was used to\r |
| 386 | * encrypt the NACK which is observed when varying only the 3 last bits of Nr\r |
| 387 | * only correct iff [NR_3] ^ NR_3 does not depend on Nr_3\r |
| 388 | */\r |
| 389 | uint32_t *lfsr_prefix_ks(uint8_t ks[8], int isodd)\r |
| 390 | {\r |
| 391 | uint32_t c, entry, *candidates = malloc(4 << 10);\r |
| 392 | int i, size = 0, good;\r |
| 393 | \r |
| 394 | if(!candidates)\r |
| 395 | return 0;\r |
| 396 | \r |
| 397 | for(i = 0; i < 1 << 21; ++i) {\r |
| 398 | for(c = 0, good = 1; good && c < 8; ++c) {\r |
| 399 | entry = i ^ fastfwd[isodd][c];\r |
| 400 | good &= (BIT(ks[c], isodd) == filter(entry >> 1));\r |
| 401 | good &= (BIT(ks[c], isodd + 2) == filter(entry));\r |
| 402 | }\r |
| 403 | if(good)\r |
| 404 | candidates[size++] = i;\r |
| 405 | }\r |
| 406 | \r |
| 407 | candidates[size] = -1;\r |
| 408 | \r |
| 409 | return candidates;\r |
| 410 | }\r |
| 411 | \r |
| 412 | /** check_pfx_parity\r |
| 413 | * helper function which eliminates possible secret states using parity bits\r |
| 414 | */\r |
| 415 | static struct Crypto1State*\r |
| 416 | check_pfx_parity(uint32_t prefix, uint32_t rresp, uint8_t parities[8][8],\r |
| 417 | uint32_t odd, uint32_t even, struct Crypto1State* sl)\r |
| 418 | {\r |
| 419 | uint32_t ks1, nr, ks2, rr, ks3, c, good = 1;\r |
| 420 | \r |
| 421 | for(c = 0; good && c < 8; ++c) {\r |
| 422 | sl->odd = odd ^ fastfwd[1][c];\r |
| 423 | sl->even = even ^ fastfwd[0][c];\r |
| 424 | \r |
| 425 | lfsr_rollback_bit(sl, 0, 0);\r |
| 426 | lfsr_rollback_bit(sl, 0, 0);\r |
| 427 | \r |
| 428 | ks3 = lfsr_rollback_bit(sl, 0, 0);\r |
| 429 | ks2 = lfsr_rollback_word(sl, 0, 0);\r |
| 430 | ks1 = lfsr_rollback_word(sl, prefix | c << 5, 1);\r |
| 431 | \r |
| 432 | nr = ks1 ^ (prefix | c << 5);\r |
| 433 | rr = ks2 ^ rresp;\r |
| 434 | \r |
| 435 | good &= parity(nr & 0x000000ff) ^ parities[c][3] ^ BIT(ks2, 24);\r |
| 436 | good &= parity(rr & 0xff000000) ^ parities[c][4] ^ BIT(ks2, 16);\r |
| 437 | good &= parity(rr & 0x00ff0000) ^ parities[c][5] ^ BIT(ks2, 8);\r |
| 438 | good &= parity(rr & 0x0000ff00) ^ parities[c][6] ^ BIT(ks2, 0);\r |
| 439 | good &= parity(rr & 0x000000ff) ^ parities[c][7] ^ ks3;\r |
| 440 | }\r |
| 441 | \r |
| 442 | return sl + good;\r |
| 443 | } \r |
| 444 | \r |
| 445 | \r |
| 446 | /** lfsr_common_prefix\r |
| 447 | * Implentation of the common prefix attack.\r |
| 448 | */\r |
| 449 | struct Crypto1State*\r |
| 450 | lfsr_common_prefix(uint32_t pfx, uint32_t rr, uint8_t ks[8], uint8_t par[8][8])\r |
| 451 | {\r |
| 452 | struct Crypto1State *statelist, *s;\r |
| 453 | uint32_t *odd, *even, *o, *e, top;\r |
| 454 | \r |
| 455 | odd = lfsr_prefix_ks(ks, 1);\r |
| 456 | even = lfsr_prefix_ks(ks, 0);\r |
| 457 | \r |
| 458 | s = statelist = malloc((sizeof *statelist) << 20);\r |
| 459 | if(!s || !odd || !even) {\r |
| 460 | free(statelist);\r |
| 461 | statelist = 0;\r |
| 462 | goto out;\r |
| 463 | }\r |
| 464 | \r |
| 465 | for(o = odd; *o + 1; ++o)\r |
| 466 | for(e = even; *e + 1; ++e)\r |
| 467 | for(top = 0; top < 64; ++top) {\r |
| 468 | *o += 1 << 21;\r |
| 469 | *e += (!(top & 7) + 1) << 21;\r |
| 470 | s = check_pfx_parity(pfx, rr, par, *o, *e, s);\r |
| 471 | }\r |
| 472 | \r |
| 473 | s->odd = s->even = 0;\r |
| 474 | out:\r |
| 475 | free(odd);\r |
| 476 | free(even);\r |
| 477 | return statelist;\r |
| 478 | }\r |