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