git.zerfleddert.de Git - proxmark3-svn/blob - client/mifarehost.c

   1 // Merlok, 2011, 2012
   2 // people from mifare@nethemba.com, 2010
   3 //
   4 // This code is licensed to you under the terms of the GNU GPL, version 2 or,
   5 // at your option, any later version. See the LICENSE.txt file for the text of
   6 // the license.
   7 //-----------------------------------------------------------------------------
   8 // mifare commands
   9 //-----------------------------------------------------------------------------
  10
  11 #include <stdio.h>
  12 #include <stdlib.h>
  13 #include <string.h>
  14 #include <pthread.h>
  15 #include "mifarehost.h"
  16 #include "proxmark3.h"
  17
  18 #define llx PRIx64
  19
  20 // MIFARE
  21 int compar_int(const void * a, const void * b) {
  22         // didn't work: (the result is truncated to 32 bits)
  23         //return (*(uint64_t*)b - *(uint64_t*)a);
  24
  25         // better:
  26         if (*(uint64_t*)b == *(uint64_t*)a) return 0;
  27         else if (*(uint64_t*)b > *(uint64_t*)a) return 1;
  28         else return -1;
  29 }
  30
  31 // Compare 16 Bits out of cryptostate
  32 int Compare16Bits(const void * a, const void * b) {
  33         if ((*(uint64_t*)b & 0x00ff000000ff0000) == (*(uint64_t*)a & 0x00ff000000ff0000)) return 0;
  34         else if ((*(uint64_t*)b & 0x00ff000000ff0000) > (*(uint64_t*)a & 0x00ff000000ff0000)) return 1;
  35         else return -1;
  36 }
  37
  38 typedef
  39         struct {
  40                 union {
  41                         struct Crypto1State *slhead;
  42                         uint64_t *keyhead;
  43                 } head;
  44                 union {
  45                         struct Crypto1State *sltail;
  46                         uint64_t *keytail;
  47                 } tail;
  48                 uint32_t len;
  49                 uint32_t uid;
  50                 uint32_t blockNo;
  51                 uint32_t keyType;
  52                 uint32_t nt;
  53                 uint32_t ks1;
  54         } StateList_t;
  55
  56
  57 // wrapper function for multi-threaded lfsr_recovery32
  58 void* nested_worker_thread(void *arg)
  59 {
  60         struct Crypto1State *p1;
  61         StateList_t *statelist = arg;
  62
  63         statelist->head.slhead = lfsr_recovery32(statelist->ks1, statelist->nt ^ statelist->uid);
  64         for (p1 = statelist->head.slhead; *(uint64_t *)p1 != 0; p1++);
  65         statelist->len = p1 - statelist->head.slhead;
  66         statelist->tail.sltail = --p1;
  67         qsort(statelist->head.slhead, statelist->len, sizeof(uint64_t), Compare16Bits);
  68
  69         return statelist->head.slhead;
  70 }
  71
  72 int mfnested(uint8_t blockNo, uint8_t keyType, uint8_t * key, uint8_t trgBlockNo, uint8_t trgKeyType, uint8_t * resultKey, bool calibrate)
  73 {
  74         uint16_t i;
  75         uint32_t uid;
  76         UsbCommand resp;
  77
  78         StateList_t statelists[2];
  79         struct Crypto1State *p1, *p2, *p3, *p4;
  80
  81         // flush queue
  82         clearCommandBuffer();
  83         //WaitForResponseTimeout(CMD_ACK,NULL,100);
  84
  85         UsbCommand c = {CMD_MIFARE_NESTED, {blockNo + keyType * 0x100, trgBlockNo + trgKeyType * 0x100, calibrate}};
  86         memcpy(c.d.asBytes, key, 6);
  87         SendCommand(&c);
  88
  89         if (!WaitForResponseTimeout(CMD_ACK, &resp, 1500)) {
  90                 return -1;
  91         }
  92
  93         if (resp.arg[0]) {
  94                 return resp.arg[0];  // error during nested
  95         }
  96
  97         memcpy(&uid, resp.d.asBytes, 4);
  98         PrintAndLog("uid:%08x trgbl=%d trgkey=%x", uid, (uint16_t)resp.arg[2] & 0xff, (uint16_t)resp.arg[2] >> 8);
  99
 100         for (i = 0; i < 2; i++) {
 101                 statelists[i].blockNo = resp.arg[2] & 0xff;
 102                 statelists[i].keyType = (resp.arg[2] >> 8) & 0xff;
 103                 statelists[i].uid = uid;
 104                 memcpy(&statelists[i].nt,  (void *)(resp.d.asBytes + 4 + i * 8 + 0), 4);
 105                 memcpy(&statelists[i].ks1, (void *)(resp.d.asBytes + 4 + i * 8 + 4), 4);
 106         }
 107
 108         // calc keys
 109
 110         pthread_t thread_id[2];
 111
 112         // create and run worker threads
 113         for (i = 0; i < 2; i++) {
 114                 pthread_create(thread_id + i, NULL, nested_worker_thread, &statelists[i]);
 115         }
 116
 117         // wait for threads to terminate:
 118         for (i = 0; i < 2; i++) {
 119                 pthread_join(thread_id[i], (void*)&statelists[i].head.slhead);
 120         }
 121
 122
 123         // the first 16 Bits of the cryptostate already contain part of our key.
 124         // Create the intersection of the two lists based on these 16 Bits and
 125         // roll back the cryptostate
 126         p1 = p3 = statelists[0].head.slhead;
 127         p2 = p4 = statelists[1].head.slhead;
 128         while (p1 <= statelists[0].tail.sltail && p2 <= statelists[1].tail.sltail) {
 129                 if (Compare16Bits(p1, p2) == 0) {
 130                         struct Crypto1State savestate, *savep = &savestate;
 131                         savestate = *p1;
 132                         while(Compare16Bits(p1, savep) == 0 && p1 <= statelists[0].tail.sltail) {
 133                                 *p3 = *p1;
 134                                 lfsr_rollback_word(p3, statelists[0].nt ^ statelists[0].uid, 0);
 135                                 p3++;
 136                                 p1++;
 137                         }
 138                         savestate = *p2;
 139                         while(Compare16Bits(p2, savep) == 0 && p2 <= statelists[1].tail.sltail) {
 140                                 *p4 = *p2;
 141                                 lfsr_rollback_word(p4, statelists[1].nt ^ statelists[1].uid, 0);
 142                                 p4++;
 143                                 p2++;
 144                         }
 145                 }
 146                 else {
 147                         while (Compare16Bits(p1, p2) == -1) p1++;
 148                         while (Compare16Bits(p1, p2) == 1) p2++;
 149                 }
 150         }
 151         p3->even = 0; p3->odd = 0;
 152         p4->even = 0; p4->odd = 0;
 153         statelists[0].len = p3 - statelists[0].head.slhead;
 154         statelists[1].len = p4 - statelists[1].head.slhead;
 155         statelists[0].tail.sltail=--p3;
 156         statelists[1].tail.sltail=--p4;
 157
 158         // the statelists now contain possible keys. The key we are searching for must be in the
 159         // intersection of both lists. Create the intersection:
 160         qsort(statelists[0].head.keyhead, statelists[0].len, sizeof(uint64_t), compar_int);
 161         qsort(statelists[1].head.keyhead, statelists[1].len, sizeof(uint64_t), compar_int);
 162
 163         uint64_t *p5, *p6, *p7;
 164         p5 = p7 = statelists[0].head.keyhead;
 165         p6 = statelists[1].head.keyhead;
 166         while (p5 <= statelists[0].tail.keytail && p6 <= statelists[1].tail.keytail) {
 167                 if (compar_int(p5, p6) == 0) {
 168                         *p7++ = *p5++;
 169                         p6++;
 170                 }
 171                 else {
 172                         while (compar_int(p5, p6) == -1) p5++;
 173                         while (compar_int(p5, p6) == 1) p6++;
 174                 }
 175         }
 176         statelists[0].len = p7 - statelists[0].head.keyhead;
 177         statelists[0].tail.keytail=--p7;
 178
 179         memset(resultKey, 0, 6);
 180         // The list may still contain several key candidates. Test each of them with mfCheckKeys
 181         for (i = 0; i < statelists[0].len; i++) {
 182                 uint8_t keyBlock[6];
 183                 uint64_t key64;
 184                 crypto1_get_lfsr(statelists[0].head.slhead + i, &key64);
 185                 num_to_bytes(key64, 6, keyBlock);
 186                 key64 = 0;
 187                 if (!mfCheckKeys(statelists[0].blockNo, statelists[0].keyType, false, 1, keyBlock, &key64)) {
 188                         num_to_bytes(key64, 6, resultKey);
 189                         break;
 190                 }
 191         }
 192
 193         free(statelists[0].head.slhead);
 194         free(statelists[1].head.slhead);
 195         return 0;
 196 }
 197
 198 int mfCheckKeys (uint8_t blockNo, uint8_t keyType, bool clear_trace, uint8_t keycnt, uint8_t * keyBlock, uint64_t * key){
 199
 200         *key = 0;
 201
 202         UsbCommand c = {CMD_MIFARE_CHKKEYS, {((blockNo & 0xff) | ((keyType&0xff)<<8)), clear_trace, keycnt}};
 203         memcpy(c.d.asBytes, keyBlock, 6 * keycnt);
 204
 205         clearCommandBuffer();
 206         SendCommand(&c);
 207         UsbCommand resp;
 208         if (!WaitForResponseTimeout(CMD_ACK,&resp,3000)) return 1;
 209         if ((resp.arg[0] & 0xff) != 0x01) return 2;
 210         *key = bytes_to_num(resp.d.asBytes, 6);
 211         return 0;
 212 }
 213
 214 // EMULATOR
 215
 216 int mfEmlGetMem(uint8_t *data, int blockNum, int blocksCount) {
 217         UsbCommand c = {CMD_MIFARE_EML_MEMGET, {blockNum, blocksCount, 0}};
 218         clearCommandBuffer();
 219         SendCommand(&c);
 220         UsbCommand resp;
 221         if (!WaitForResponseTimeout(CMD_ACK,&resp,1500)) return 1;
 222         memcpy(data, resp.d.asBytes, blocksCount * 16);
 223         return 0;
 224 }
 225
 226 int mfEmlSetMem(uint8_t *data, int blockNum, int blocksCount) {
 227         return mfEmlSetMem_xt(data, blockNum, blocksCount, 16);
 228 }
 229
 230 int mfEmlSetMem_xt(uint8_t *data, int blockNum, int blocksCount, int blockBtWidth) {
 231         UsbCommand c = {CMD_MIFARE_EML_MEMSET, {blockNum, blocksCount, blockBtWidth}};
 232         memcpy(c.d.asBytes, data, blocksCount * blockBtWidth);
 233
 234         clearCommandBuffer();
 235         SendCommand(&c);
 236         return 0;
 237 }
 238
 239 // "MAGIC" CARD
 240
 241 int mfCSetUID(uint8_t *uid, uint8_t *atqa, uint8_t *sak, uint8_t *oldUID, uint8_t wipecard) {
 242
 243         uint8_t params = MAGIC_SINGLE;
 244         uint8_t block0[16];
 245         memset(block0, 0x00, sizeof(block0));
 246
 247
 248         int old = mfCGetBlock(0, block0, params);
 249         if (old == 0) {
 250                 PrintAndLog("old block 0:  %s", sprint_hex(block0, sizeof(block0)));
 251         } else {
 252                 PrintAndLog("Couldn't get old data. Will write over the last bytes of Block 0.");
 253         }
 254
 255         // fill in the new values
 256         // UID
 257         memcpy(block0, uid, 4);
 258         // Mifare UID BCC
 259         block0[4] = block0[0]^block0[1]^block0[2]^block0[3];
 260         // mifare classic SAK(byte 5) and ATQA(byte 6 and 7, reversed)
 261         if ( sak != NULL )
 262                 block0[5]=sak[0];
 263
 264         if ( atqa != NULL ) {
 265                 block0[6]=atqa[1];
 266                 block0[7]=atqa[0];
 267         }
 268         PrintAndLog("new block 0:  %s", sprint_hex(block0,16));
 269
 270         if ( wipecard )          params |= MAGIC_WIPE;
 271         if ( oldUID == NULL) params |= MAGIC_UID;
 272
 273         return mfCSetBlock(0, block0, oldUID, params);
 274 }
 275
 276 int mfCSetBlock(uint8_t blockNo, uint8_t *data, uint8_t *uid, uint8_t params) {
 277
 278         uint8_t isOK = 0;
 279         UsbCommand c = {CMD_MIFARE_CSETBLOCK, {params, blockNo, 0}};
 280         memcpy(c.d.asBytes, data, 16);
 281         clearCommandBuffer();
 282         SendCommand(&c);
 283         UsbCommand resp;
 284         if (WaitForResponseTimeout(CMD_ACK, &resp, 1500)) {
 285                 isOK  = resp.arg[0] & 0xff;
 286                 if (uid != NULL)
 287                         memcpy(uid, resp.d.asBytes, 4);
 288                 if (!isOK)
 289                         return 2;
 290         } else {
 291                 PrintAndLog("Command execute timeout");
 292                 return 1;
 293         }
 294         return 0;
 295 }
 296
 297 int mfCGetBlock(uint8_t blockNo, uint8_t *data, uint8_t params) {
 298         uint8_t isOK = 0;
 299         UsbCommand c = {CMD_MIFARE_CGETBLOCK, {params, blockNo, 0}};
 300         clearCommandBuffer();
 301         SendCommand(&c);
 302         UsbCommand resp;
 303         if (WaitForResponseTimeout(CMD_ACK,&resp,1500)) {
 304                 isOK  = resp.arg[0] & 0xff;
 305                 memcpy(data, resp.d.asBytes, 16);
 306                 if (!isOK) return 2;
 307         } else {
 308                 PrintAndLog("Command execute timeout");
 309                 return 1;
 310         }
 311         return 0;
 312 }
 313
 314 // SNIFFER
 315
 316 // constants
 317 static uint8_t trailerAccessBytes[4] = {0x08, 0x77, 0x8F, 0x00};
 318
 319 // variables
 320 char logHexFileName[FILE_PATH_SIZE] = {0x00};
 321 static uint8_t traceCard[4096] = {0x00};
 322 static char traceFileName[FILE_PATH_SIZE] = {0x00};
 323 static int traceState = TRACE_IDLE;
 324 static uint8_t traceCurBlock = 0;
 325 static uint8_t traceCurKey = 0;
 326
 327 struct Crypto1State *traceCrypto1 = NULL;
 328
 329 struct Crypto1State *revstate = NULL;
 330
 331 uint64_t key = 0;
 332 uint32_t ks2 = 0;
 333 uint32_t ks3 = 0;
 334
 335 uint32_t uid = 0;     // serial number
 336 uint32_t nt =0;      // tag challenge
 337 uint32_t nr_enc =0;  // encrypted reader challenge
 338 uint32_t ar_enc =0;  // encrypted reader response
 339 uint32_t at_enc =0;  // encrypted tag response
 340
 341 int isTraceCardEmpty(void) {
 342         return ((traceCard[0] == 0) && (traceCard[1] == 0) && (traceCard[2] == 0) && (traceCard[3] == 0));
 343 }
 344
 345 int isBlockEmpty(int blockN) {
 346         for (int i = 0; i < 16; i++)
 347                 if (traceCard[blockN * 16 + i] != 0) return 0;
 348
 349         return 1;
 350 }
 351
 352 int isBlockTrailer(int blockN) {
 353  return ((blockN & 0x03) == 0x03);
 354 }
 355
 356 int loadTraceCard(uint8_t *tuid) {
 357         FILE * f;
 358         char buf[64] = {0x00};
 359         uint8_t buf8[64] = {0x00};
 360         int i, blockNum;
 361
 362         if (!isTraceCardEmpty())
 363                 saveTraceCard();
 364
 365         memset(traceCard, 0x00, 4096);
 366         memcpy(traceCard, tuid + 3, 4);
 367
 368         FillFileNameByUID(traceFileName, tuid, ".eml", 7);
 369
 370         f = fopen(traceFileName, "r");
 371         if (!f) return 1;
 372
 373         blockNum = 0;
 374
 375         while(!feof(f)){
 376
 377                 memset(buf, 0, sizeof(buf));
 378                 if (fgets(buf, sizeof(buf), f) == NULL) {
 379                         PrintAndLog("File reading error.");
 380                         fclose(f);
 381                         return 2;
 382                 }
 383
 384                 if (strlen(buf) < 32){
 385                         if (feof(f)) break;
 386                         PrintAndLog("File content error. Block data must include 32 HEX symbols");
 387                         fclose(f);
 388                         return 2;
 389                 }
 390                 for (i = 0; i < 32; i += 2)
 391                         sscanf(&buf[i], "%02x", (unsigned int *)&buf8[i / 2]);
 392
 393                 memcpy(traceCard + blockNum * 16, buf8, 16);
 394
 395                 blockNum++;
 396         }
 397         fclose(f);
 398
 399         return 0;
 400 }
 401
 402 int saveTraceCard(void) {
 403         FILE * f;
 404
 405         if ((!strlen(traceFileName)) || (isTraceCardEmpty())) return 0;
 406
 407         f = fopen(traceFileName, "w+");
 408         if ( !f ) return 1;
 409
 410         for (int i = 0; i < 64; i++) {  // blocks
 411                 for (int j = 0; j < 16; j++)  // bytes
 412                         fprintf(f, "%02x", *(traceCard + i * 16 + j));
 413                 fprintf(f,"\n");
 414         }
 415         fclose(f);
 416         return 0;
 417 }
 418
 419 int mfTraceInit(uint8_t *tuid, uint8_t *atqa, uint8_t sak, bool wantSaveToEmlFile) {
 420
 421         if (traceCrypto1)
 422                 crypto1_destroy(traceCrypto1);
 423
 424         traceCrypto1 = NULL;
 425
 426         if (wantSaveToEmlFile)
 427                 loadTraceCard(tuid);
 428
 429         traceCard[4] = traceCard[0] ^ traceCard[1] ^ traceCard[2] ^ traceCard[3];
 430         traceCard[5] = sak;
 431         memcpy(&traceCard[6], atqa, 2);
 432         traceCurBlock = 0;
 433         uid = bytes_to_num(tuid + 3, 4);
 434
 435         traceState = TRACE_IDLE;
 436
 437         return 0;
 438 }
 439
 440 void mf_crypto1_decrypt(struct Crypto1State *pcs, uint8_t *data, int len, bool isEncrypted){
 441         uint8_t bt = 0;
 442         int i;
 443
 444         if (len != 1) {
 445                 for (i = 0; i < len; i++)
 446                         data[i] = crypto1_byte(pcs, 0x00, isEncrypted) ^ data[i];
 447         } else {
 448                 bt = 0;
 449                 for (i = 0; i < 4; i++)
 450                         bt |= (crypto1_bit(pcs, 0, isEncrypted) ^ BIT(data[0], i)) << i;
 451
 452                 data[0] = bt;
 453         }
 454         return;
 455 }
 456
 457
 458 int mfTraceDecode(uint8_t *data_src, int len, bool wantSaveToEmlFile) {
 459         uint8_t data[64];
 460
 461         if (traceState == TRACE_ERROR) return 1;
 462         if (len > 64) {
 463                 traceState = TRACE_ERROR;
 464                 return 1;
 465         }
 466
 467         memcpy(data, data_src, len);
 468         if ((traceCrypto1) && ((traceState == TRACE_IDLE) || (traceState > TRACE_AUTH_OK))) {
 469                 mf_crypto1_decrypt(traceCrypto1, data, len, 0);
 470                 PrintAndLog("dec> %s", sprint_hex(data, len));
 471                 AddLogHex(logHexFileName, "dec> ", data, len);
 472         }
 473
 474         switch (traceState) {
 475         case TRACE_IDLE:
 476                 // check packet crc16!
 477                 if ((len >= 4) && (!CheckCrc14443(CRC_14443_A, data, len))) {
 478                         PrintAndLog("dec> CRC ERROR!!!");
 479                         AddLogLine(logHexFileName, "dec> ", "CRC ERROR!!!");
 480                         traceState = TRACE_ERROR;  // do not decrypt the next commands
 481                         return 1;
 482                 }
 483
 484                 // AUTHENTICATION
 485                 if ((len == 4) && ((data[0] == 0x60) || (data[0] == 0x61))) {
 486                         traceState = TRACE_AUTH1;
 487                         traceCurBlock = data[1];
 488                         traceCurKey = data[0] == 60 ? 1:0;
 489                         return 0;
 490                 }
 491
 492                 // READ
 493                 if ((len ==4) && ((data[0] == 0x30))) {
 494                         traceState = TRACE_READ_DATA;
 495                         traceCurBlock = data[1];
 496                         return 0;
 497                 }
 498
 499                 // WRITE
 500                 if ((len ==4) && ((data[0] == 0xA0))) {
 501                         traceState = TRACE_WRITE_OK;
 502                         traceCurBlock = data[1];
 503                         return 0;
 504                 }
 505
 506                 // HALT
 507                 if ((len ==4) && ((data[0] == 0x50) && (data[1] == 0x00))) {
 508                         traceState = TRACE_ERROR;  // do not decrypt the next commands
 509                         return 0;
 510                 }
 511
 512                 return 0;
 513         break;
 514
 515         case TRACE_READ_DATA:
 516                 if (len == 18) {
 517                         traceState = TRACE_IDLE;
 518
 519                         if (isBlockTrailer(traceCurBlock)) {
 520                                 memcpy(traceCard + traceCurBlock * 16 + 6, data + 6, 4);
 521                         } else {
 522                                 memcpy(traceCard + traceCurBlock * 16, data, 16);
 523                         }
 524                         if (wantSaveToEmlFile) saveTraceCard();
 525                         return 0;
 526                 } else {
 527                         traceState = TRACE_ERROR;
 528                         return 1;
 529                 }
 530         break;
 531
 532         case TRACE_WRITE_OK:
 533                 if ((len == 1) && (data[0] == 0x0a)) {
 534                         traceState = TRACE_WRITE_DATA;
 535
 536                         return 0;
 537                 } else {
 538                         traceState = TRACE_ERROR;
 539                         return 1;
 540                 }
 541         break;
 542
 543         case TRACE_WRITE_DATA:
 544                 if (len == 18) {
 545                         traceState = TRACE_IDLE;
 546
 547                         memcpy(traceCard + traceCurBlock * 16, data, 16);
 548                         if (wantSaveToEmlFile) saveTraceCard();
 549                         return 0;
 550                 } else {
 551                         traceState = TRACE_ERROR;
 552                         return 1;
 553                 }
 554         break;
 555
 556         case TRACE_AUTH1:
 557                 if (len == 4) {
 558                         traceState = TRACE_AUTH2;
 559                         nt = bytes_to_num(data, 4);
 560                         return 0;
 561                 } else {
 562                         traceState = TRACE_ERROR;
 563                         return 1;
 564                 }
 565         break;
 566
 567         case TRACE_AUTH2:
 568                 if (len == 8) {
 569                         traceState = TRACE_AUTH_OK;
 570
 571                         nr_enc = bytes_to_num(data, 4);
 572                         ar_enc = bytes_to_num(data + 4, 4);
 573                         return 0;
 574                 } else {
 575                         traceState = TRACE_ERROR;
 576                         return 1;
 577                 }
 578         break;
 579
 580         case TRACE_AUTH_OK:
 581                 if (len ==4) {
 582                         traceState = TRACE_IDLE;
 583
 584                         at_enc = bytes_to_num(data, 4);
 585
 586                         //  decode key here)
 587                         ks2 = ar_enc ^ prng_successor(nt, 64);
 588                         ks3 = at_enc ^ prng_successor(nt, 96);
 589                         revstate = lfsr_recovery64(ks2, ks3);
 590                         lfsr_rollback_word(revstate, 0, 0);
 591                         lfsr_rollback_word(revstate, 0, 0);
 592                         lfsr_rollback_word(revstate, nr_enc, 1);
 593                         lfsr_rollback_word(revstate, uid ^ nt, 0);
 594
 595                         crypto1_get_lfsr(revstate, &key);
 596                         printf("Key: %012"llx"\n",key);
 597                         AddLogUint64(logHexFileName, "key: ", key);
 598
 599                         int blockShift = ((traceCurBlock & 0xFC) + 3) * 16;
 600                         if (isBlockEmpty((traceCurBlock & 0xFC) + 3)) memcpy(traceCard + blockShift + 6, trailerAccessBytes, 4);
 601
 602                         if (traceCurKey) {
 603                                 num_to_bytes(key, 6, traceCard + blockShift + 10);
 604                         } else {
 605                                 num_to_bytes(key, 6, traceCard + blockShift);
 606                         }
 607                         if (wantSaveToEmlFile) saveTraceCard();
 608
 609                         if (traceCrypto1) {
 610                                 crypto1_destroy(traceCrypto1);
 611                         }
 612
 613                         // set cryptosystem state
 614                         traceCrypto1 = lfsr_recovery64(ks2, ks3);
 615
 616 //      nt = crypto1_word(traceCrypto1, nt ^ uid, 1) ^ nt;
 617
 618         /*      traceCrypto1 = crypto1_create(key); // key in lfsr
 619                 crypto1_word(traceCrypto1, nt ^ uid, 0);
 620                 crypto1_word(traceCrypto1, ar, 1);
 621                 crypto1_word(traceCrypto1, 0, 0);
 622                 crypto1_word(traceCrypto1, 0, 0);*/
 623
 624                         return 0;
 625                 } else {
 626                         traceState = TRACE_ERROR;
 627                         return 1;
 628                 }
 629         break;
 630
 631         default:
 632                 traceState = TRACE_ERROR;
 633                 return 1;
 634         }
 635
 636         return 0;
 637 }
 638
 639 int tryDecryptWord(uint32_t nt, uint32_t ar_enc, uint32_t at_enc, uint8_t *data, int len){
 640         /*
 641         uint32_t nt;      // tag challenge
 642         uint32_t nr_enc;  // encrypted reader challenge
 643         uint32_t ar_enc;  // encrypted reader response
 644         uint32_t at_enc;  // encrypted tag response
 645         */
 646
 647         struct Crypto1State *pcs = NULL;
 648
 649         ks2 = ar_enc ^ prng_successor(nt, 64);
 650         ks3 = at_enc ^ prng_successor(nt, 96);
 651
 652         PrintAndLog("Decrypting data with:");
 653         PrintAndLog("      nt: %08x",nt);
 654         PrintAndLog("  ar_enc: %08x",ar_enc);
 655         PrintAndLog("  at_enc: %08x",at_enc);
 656         PrintAndLog("\nEncrypted data: [%s]", sprint_hex(data,len) );
 657
 658         pcs = lfsr_recovery64(ks2, ks3);
 659         mf_crypto1_decrypt(pcs, data, len, FALSE);
 660         PrintAndLog("Decrypted data: [%s]", sprint_hex(data,len) );
 661         crypto1_destroy(pcs);
 662         return 0;
 663 }