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 //#include "radixsort.h"
  18
  19 // MIFARE
  20 int compar_int(const void * a, const void * b) {
  21         // didn't work: (the result is truncated to 32 bits)
  22         //return (*(uint64_t*)b - *(uint64_t*)a);
  23
  24         // better:
  25         /*if (*(uint64_t*)b < *(uint64_t*)a) return -1;
  26         if (*(uint64_t*)b > *(uint64_t*)a) return 1;
  27         return 0;
  28 */
  29         return (*(uint64_t*)b > *(uint64_t*)a) - (*(uint64_t*)b < *(uint64_t*)a);
  30 }
  31
  32 // Compare 16 Bits out of cryptostate
  33 int Compare16Bits(const void * a, const void * b) {
  34
  35 /*
  36          if ((*(uint64_t*)b & 0x00ff000000ff0000) < (*(uint64_t*)a & 0x00ff000000ff0000)) return -1;
  37          if ((*(uint64_t*)b & 0x00ff000000ff0000) > (*(uint64_t*)a & 0x00ff000000ff0000)) return 1;
  38          return 0;
  39 */
  40         return
  41                 ((*(uint64_t*)b & 0x00ff000000ff0000) > (*(uint64_t*)a & 0x00ff000000ff0000))
  42                 -
  43                 ((*(uint64_t*)b & 0x00ff000000ff0000) < (*(uint64_t*)a & 0x00ff000000ff0000))
  44                 ;
  45 }
  46
  47 typedef
  48         struct {
  49                 union {
  50                         struct Crypto1State *slhead;
  51                         uint64_t *keyhead;
  52                 } head;
  53                 union {
  54                         struct Crypto1State *sltail;
  55                         uint64_t *keytail;
  56                 } tail;
  57                 uint32_t len;
  58                 uint32_t uid;
  59                 uint32_t blockNo;
  60                 uint32_t keyType;
  61                 uint32_t nt;
  62                 uint32_t ks1;
  63         } StateList_t;
  64
  65
  66 // wrapper function for multi-threaded lfsr_recovery32
  67 void* nested_worker_thread(void *arg)
  68 {
  69         struct Crypto1State *p1;
  70         StateList_t *statelist = arg;
  71
  72         statelist->head.slhead = lfsr_recovery32(statelist->ks1, statelist->nt ^ statelist->uid);
  73
  74         for (p1 = statelist->head.slhead; *(uint64_t *)p1 != 0; p1++);
  75
  76         statelist->len = p1 - statelist->head.slhead;
  77         statelist->tail.sltail = --p1;
  78         qsort(statelist->head.slhead, statelist->len, sizeof(uint64_t), Compare16Bits);
  79
  80         return statelist->head.slhead;
  81 }
  82
  83 int mfnested(uint8_t blockNo, uint8_t keyType, uint8_t * key, uint8_t trgBlockNo, uint8_t trgKeyType, uint8_t * resultKey, bool calibrate)
  84 {
  85         uint16_t i;
  86         uint32_t uid;
  87         UsbCommand resp;
  88         StateList_t statelists[2];
  89         struct Crypto1State *p1, *p2, *p3, *p4;
  90
  91         UsbCommand c = {CMD_MIFARE_NESTED, {blockNo + keyType * 0x100, trgBlockNo + trgKeyType * 0x100, calibrate}};
  92         memcpy(c.d.asBytes, key, 6);
  93         clearCommandBuffer();
  94         SendCommand(&c);
  95         if (!WaitForResponseTimeout(CMD_ACK, &resp, 1500)) return -1;
  96
  97         // error during nested
  98         if (resp.arg[0]) return resp.arg[0];
  99
 100         memcpy(&uid, resp.d.asBytes, 4);
 101
 102         for (i = 0; i < 2; i++) {
 103                 statelists[i].blockNo = resp.arg[2] & 0xff;
 104                 statelists[i].keyType = (resp.arg[2] >> 8) & 0xff;
 105                 statelists[i].uid = uid;
 106                 memcpy(&statelists[i].nt,  (void *)(resp.d.asBytes + 4 + i * 8 + 0), 4);
 107                 memcpy(&statelists[i].ks1, (void *)(resp.d.asBytes + 4 + i * 8 + 4), 4);
 108         }
 109
 110         // calc keys
 111         pthread_t thread_id[2];
 112
 113         // create and run worker threads
 114         for (i = 0; i < 2; i++)
 115                 pthread_create(thread_id + i, NULL, nested_worker_thread, &statelists[i]);
 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         // the first 16 Bits of the cryptostate already contain part of our key.
 122         // Create the intersection of the two lists based on these 16 Bits and
 123         // roll back the cryptostate
 124         p1 = p3 = statelists[0].head.slhead;
 125         p2 = p4 = statelists[1].head.slhead;
 126
 127         while (p1 <= statelists[0].tail.sltail && p2 <= statelists[1].tail.sltail) {
 128                 if (Compare16Bits(p1, p2) == 0) {
 129
 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
 152         p3->even = 0; p3->odd = 0;
 153         p4->even = 0; p4->odd = 0;
 154         statelists[0].len = p3 - statelists[0].head.slhead;
 155         statelists[1].len = p4 - statelists[1].head.slhead;
 156         statelists[0].tail.sltail=--p3;
 157         statelists[1].tail.sltail=--p4;
 158
 159         // the statelists now contain possible keys. The key we are searching for must be in the
 160         // intersection of both lists. Create the intersection:
 161         qsort(statelists[0].head.keyhead, statelists[0].len, sizeof(uint64_t), compar_int);
 162         qsort(statelists[1].head.keyhead, statelists[1].len, sizeof(uint64_t), compar_int);
 163
 164         uint64_t *p5, *p6, *p7;
 165         p5 = p7 = statelists[0].head.keyhead;
 166         p6 = statelists[1].head.keyhead;
 167         while (p5 <= statelists[0].tail.keytail && p6 <= statelists[1].tail.keytail) {
 168                 if (compar_int(p5, p6) == 0) {
 169                         *p7++ = *p5++;
 170                         p6++;
 171                 }
 172                 else {
 173                         while (compar_int(p5, p6) == -1) p5++;
 174                         while (compar_int(p5, p6) == 1) p6++;
 175                 }
 176         }
 177         statelists[0].len = p7 - statelists[0].head.keyhead;
 178         statelists[0].tail.keytail = --p7;
 179
 180         memset(resultKey, 0, 6);
 181         uint64_t key64 = 0;
 182
 183         // The list may still contain several key candidates. Test each of them with mfCheckKeys
 184         // uint32_t max_keys = keycnt > (USB_CMD_DATA_SIZE/6) ? (USB_CMD_DATA_SIZE/6) : keycnt;
 185
 186         uint32_t numOfCandidates = statelists[0].len;
 187         if ( numOfCandidates > 0 ) {
 188
 189                 uint8_t keyBlock[USB_CMD_DATA_SIZE] = {0x00};
 190
 191                 for (i = 0; i < numOfCandidates; ++i){
 192                         crypto1_get_lfsr(statelists[0].head.slhead + i, &key64);
 193                         num_to_bytes(key64, 6, keyBlock + i * 6);
 194                 }
 195
 196                 if (!mfCheckKeys(statelists[0].blockNo, statelists[0].keyType, false, numOfCandidates, keyBlock, &key64)) {
 197                         free(statelists[0].head.slhead);
 198                         free(statelists[1].head.slhead);
 199                         num_to_bytes(key64, 6, resultKey);
 200
 201                         PrintAndLog("UID: %08x target block:%3u key type: %c  -- Found key [%012"llx"]",
 202                                 uid,
 203                                 (uint16_t)resp.arg[2] & 0xff,
 204                                 (resp.arg[2] >> 8) ? 'B' : 'A',
 205                                 key64
 206                         );
 207                         return -5;
 208                 }
 209
 210         }
 211         PrintAndLog("UID: %08x target block:%3u key type: %c",
 212                         uid,
 213                         (uint16_t)resp.arg[2] & 0xff,
 214                         (resp.arg[2] >> 8) ? 'B' : 'A'
 215         );
 216
 217         free(statelists[0].head.slhead);
 218         free(statelists[1].head.slhead);
 219         return -4;
 220 }
 221
 222 int mfCheckKeys (uint8_t blockNo, uint8_t keyType, bool clear_trace, uint8_t keycnt, uint8_t * keyBlock, uint64_t * key){
 223
 224         *key = 0;
 225         UsbCommand c = {CMD_MIFARE_CHKKEYS, { (blockNo | (keyType<<8)), clear_trace, keycnt}};
 226         memcpy(c.d.asBytes, keyBlock, 6 * keycnt);
 227         clearCommandBuffer();
 228         SendCommand(&c);
 229         UsbCommand resp;
 230         if (!WaitForResponseTimeout(CMD_ACK,&resp, 3000)) return 1;
 231         if ((resp.arg[0] & 0xff) != 0x01) return 2;
 232         *key = bytes_to_num(resp.d.asBytes, 6);
 233         return 0;
 234 }
 235
 236 // EMULATOR
 237
 238 int mfEmlGetMem(uint8_t *data, int blockNum, int blocksCount) {
 239         UsbCommand c = {CMD_MIFARE_EML_MEMGET, {blockNum, blocksCount, 0}};
 240         clearCommandBuffer();
 241         SendCommand(&c);
 242         UsbCommand resp;
 243         if (!WaitForResponseTimeout(CMD_ACK,&resp,1500)) return 1;
 244         memcpy(data, resp.d.asBytes, blocksCount * 16);
 245         return 0;
 246 }
 247
 248 int mfEmlSetMem(uint8_t *data, int blockNum, int blocksCount) {
 249         return mfEmlSetMem_xt(data, blockNum, blocksCount, 16);
 250 }
 251
 252 int mfEmlSetMem_xt(uint8_t *data, int blockNum, int blocksCount, int blockBtWidth) {
 253         UsbCommand c = {CMD_MIFARE_EML_MEMSET, {blockNum, blocksCount, blockBtWidth}};
 254         memcpy(c.d.asBytes, data, blocksCount * blockBtWidth);
 255
 256         clearCommandBuffer();
 257         SendCommand(&c);
 258         return 0;
 259 }
 260
 261 // "MAGIC" CARD
 262
 263 int mfCSetUID(uint8_t *uid, uint8_t *atqa, uint8_t *sak, uint8_t *oldUID, uint8_t wipecard) {
 264
 265         uint8_t params = MAGIC_SINGLE;
 266         uint8_t block0[16];
 267         memset(block0, 0x00, sizeof(block0));
 268
 269         int old = mfCGetBlock(0, block0, params);
 270         if (old == 0)
 271                 PrintAndLog("old block 0:  %s", sprint_hex(block0, sizeof(block0)));
 272         else
 273                 PrintAndLog("Couldn't get old data. Will write over the last bytes of Block 0.");
 274
 275         // fill in the new values
 276         // UID
 277         memcpy(block0, uid, 4);
 278         // Mifare UID BCC
 279         block0[4] = block0[0]^block0[1]^block0[2]^block0[3];
 280         // mifare classic SAK(byte 5) and ATQA(byte 6 and 7, reversed)
 281         if ( sak != NULL )
 282                 block0[5]=sak[0];
 283
 284         if ( atqa != NULL ) {
 285                 block0[6]=atqa[1];
 286                 block0[7]=atqa[0];
 287         }
 288         PrintAndLog("new block 0:  %s", sprint_hex(block0,16));
 289
 290         if ( wipecard )          params |= MAGIC_WIPE;
 291         if ( oldUID == NULL) params |= MAGIC_UID;
 292
 293         return mfCSetBlock(0, block0, oldUID, params);
 294 }
 295
 296 int mfCSetBlock(uint8_t blockNo, uint8_t *data, uint8_t *uid, uint8_t params) {
 297
 298         uint8_t isOK = 0;
 299         UsbCommand c = {CMD_MIFARE_CSETBLOCK, {params, blockNo, 0}};
 300         memcpy(c.d.asBytes, data, 16);
 301         clearCommandBuffer();
 302         SendCommand(&c);
 303         UsbCommand resp;
 304         if (WaitForResponseTimeout(CMD_ACK, &resp, 1500)) {
 305                 isOK  = resp.arg[0] & 0xff;
 306                 if (uid != NULL)
 307                         memcpy(uid, resp.d.asBytes, 4);
 308                 if (!isOK)
 309                         return 2;
 310         } else {
 311                 PrintAndLog("Command execute timeout");
 312                 return 1;
 313         }
 314         return 0;
 315 }
 316
 317 int mfCGetBlock(uint8_t blockNo, uint8_t *data, uint8_t params) {
 318         uint8_t isOK = 0;
 319         UsbCommand c = {CMD_MIFARE_CGETBLOCK, {params, blockNo, 0}};
 320         clearCommandBuffer();
 321         SendCommand(&c);
 322         UsbCommand resp;
 323         if (WaitForResponseTimeout(CMD_ACK,&resp,1500)) {
 324                 isOK  = resp.arg[0] & 0xff;
 325                 memcpy(data, resp.d.asBytes, 16);
 326                 if (!isOK) return 2;
 327         } else {
 328                 PrintAndLog("Command execute timeout");
 329                 return 1;
 330         }
 331         return 0;
 332 }
 333
 334 // SNIFFER
 335
 336 // constants
 337 static uint8_t trailerAccessBytes[4] = {0x08, 0x77, 0x8F, 0x00};
 338
 339 // variables
 340 char logHexFileName[FILE_PATH_SIZE] = {0x00};
 341 static uint8_t traceCard[4096] = {0x00};
 342 static char traceFileName[FILE_PATH_SIZE] = {0x00};
 343 static int traceState = TRACE_IDLE;
 344 static uint8_t traceCurBlock = 0;
 345 static uint8_t traceCurKey = 0;
 346
 347 struct Crypto1State *traceCrypto1 = NULL;
 348
 349 struct Crypto1State *revstate = NULL;
 350
 351 uint64_t key = 0;
 352 uint32_t ks2 = 0;
 353 uint32_t ks3 = 0;
 354
 355 uint32_t uid = 0;     // serial number
 356 uint32_t nt =0;      // tag challenge
 357 uint32_t nr_enc =0;  // encrypted reader challenge
 358 uint32_t ar_enc =0;  // encrypted reader response
 359 uint32_t at_enc =0;  // encrypted tag response
 360
 361 int isTraceCardEmpty(void) {
 362         return ((traceCard[0] == 0) && (traceCard[1] == 0) && (traceCard[2] == 0) && (traceCard[3] == 0));
 363 }
 364
 365 int isBlockEmpty(int blockN) {
 366         for (int i = 0; i < 16; i++)
 367                 if (traceCard[blockN * 16 + i] != 0) return 0;
 368
 369         return 1;
 370 }
 371
 372 int isBlockTrailer(int blockN) {
 373         return ((blockN & 0x03) == 0x03);
 374 }
 375
 376 int loadTraceCard(uint8_t *tuid) {
 377         FILE * f;
 378         char buf[64] = {0x00};
 379         uint8_t buf8[64] = {0x00};
 380         int i, blockNum;
 381
 382         if (!isTraceCardEmpty())
 383                 saveTraceCard();
 384
 385         memset(traceCard, 0x00, 4096);
 386         memcpy(traceCard, tuid + 3, 4);
 387
 388         FillFileNameByUID(traceFileName, tuid, ".eml", 7);
 389
 390         f = fopen(traceFileName, "r");
 391         if (!f) return 1;
 392
 393         blockNum = 0;
 394
 395         while(!feof(f)){
 396
 397                 memset(buf, 0, sizeof(buf));
 398                 if (fgets(buf, sizeof(buf), f) == NULL) {
 399                         PrintAndLog("File reading error.");
 400                         fclose(f);
 401                         return 2;
 402                 }
 403
 404                 if (strlen(buf) < 32){
 405                         if (feof(f)) break;
 406                         PrintAndLog("File content error. Block data must include 32 HEX symbols");
 407                         fclose(f);
 408                         return 2;
 409                 }
 410                 for (i = 0; i < 32; i += 2)
 411                         sscanf(&buf[i], "%02x", (unsigned int *)&buf8[i / 2]);
 412
 413                 memcpy(traceCard + blockNum * 16, buf8, 16);
 414
 415                 blockNum++;
 416         }
 417         fclose(f);
 418
 419         return 0;
 420 }
 421
 422 int saveTraceCard(void) {
 423         FILE * f;
 424
 425         if ((!strlen(traceFileName)) || (isTraceCardEmpty())) return 0;
 426
 427         f = fopen(traceFileName, "w+");
 428         if ( !f ) return 1;
 429
 430         for (int i = 0; i < 64; i++) {  // blocks
 431                 for (int j = 0; j < 16; j++)  // bytes
 432                         fprintf(f, "%02x", *(traceCard + i * 16 + j));
 433                 fprintf(f,"\n");
 434         }
 435         fclose(f);
 436         return 0;
 437 }
 438
 439 int mfTraceInit(uint8_t *tuid, uint8_t *atqa, uint8_t sak, bool wantSaveToEmlFile) {
 440
 441         if (traceCrypto1)
 442                 crypto1_destroy(traceCrypto1);
 443
 444         traceCrypto1 = NULL;
 445
 446         if (wantSaveToEmlFile)
 447                 loadTraceCard(tuid);
 448
 449         traceCard[4] = traceCard[0] ^ traceCard[1] ^ traceCard[2] ^ traceCard[3];
 450         traceCard[5] = sak;
 451         memcpy(&traceCard[6], atqa, 2);
 452         traceCurBlock = 0;
 453         uid = bytes_to_num(tuid + 3, 4);
 454
 455         traceState = TRACE_IDLE;
 456
 457         return 0;
 458 }
 459
 460 void mf_crypto1_decrypt(struct Crypto1State *pcs, uint8_t *data, int len, bool isEncrypted){
 461         uint8_t bt = 0;
 462         int i;
 463
 464         if (len != 1) {
 465                 for (i = 0; i < len; i++)
 466                         data[i] = crypto1_byte(pcs, 0x00, isEncrypted) ^ data[i];
 467         } else {
 468                 bt = 0;
 469                 bt |= (crypto1_bit(pcs, 0, isEncrypted) ^ BIT(data[0], 0)) << 0;
 470                 bt |= (crypto1_bit(pcs, 0, isEncrypted) ^ BIT(data[0], 1)) << 1;
 471                 bt |= (crypto1_bit(pcs, 0, isEncrypted) ^ BIT(data[0], 2)) << 2;
 472                 bt |= (crypto1_bit(pcs, 0, isEncrypted) ^ BIT(data[0], 3)) << 3;
 473                 data[0] = bt;
 474         }
 475         return;
 476 }
 477
 478 int mfTraceDecode(uint8_t *data_src, int len, bool wantSaveToEmlFile) {
 479
 480         uint8_t data[64];
 481
 482         if (traceState == TRACE_ERROR) return 1;
 483
 484         if (len > 64) {
 485                 traceState = TRACE_ERROR;
 486                 return 1;
 487         }
 488
 489         memcpy(data, data_src, len);
 490         if ((traceCrypto1) && ((traceState == TRACE_IDLE) || (traceState > TRACE_AUTH_OK))) {
 491                 mf_crypto1_decrypt(traceCrypto1, data, len, 0);
 492                 PrintAndLog("dec> %s", sprint_hex(data, len));
 493                 AddLogHex(logHexFileName, "dec> ", data, len);
 494         }
 495
 496         switch (traceState) {
 497         case TRACE_IDLE:
 498                 // check packet crc16!
 499                 if ((len >= 4) && (!CheckCrc14443(CRC_14443_A, data, len))) {
 500                         PrintAndLog("dec> CRC ERROR!!!");
 501                         AddLogLine(logHexFileName, "dec> ", "CRC ERROR!!!");
 502                         traceState = TRACE_ERROR;  // do not decrypt the next commands
 503                         return 1;
 504                 }
 505
 506                 // AUTHENTICATION
 507                 if ((len == 4) && ((data[0] == 0x60) || (data[0] == 0x61))) {
 508                         traceState = TRACE_AUTH1;
 509                         traceCurBlock = data[1];
 510                         traceCurKey = data[0] == 60 ? 1:0;
 511                         return 0;
 512                 }
 513
 514                 // READ
 515                 if ((len ==4) && ((data[0] == 0x30))) {
 516                         traceState = TRACE_READ_DATA;
 517                         traceCurBlock = data[1];
 518                         return 0;
 519                 }
 520
 521                 // WRITE
 522                 if ((len ==4) && ((data[0] == 0xA0))) {
 523                         traceState = TRACE_WRITE_OK;
 524                         traceCurBlock = data[1];
 525                         return 0;
 526                 }
 527
 528                 // HALT
 529                 if ((len ==4) && ((data[0] == 0x50) && (data[1] == 0x00))) {
 530                         traceState = TRACE_ERROR;  // do not decrypt the next commands
 531                         return 0;
 532                 }
 533
 534                 return 0;
 535         break;
 536
 537         case TRACE_READ_DATA:
 538                 if (len == 18) {
 539                         traceState = TRACE_IDLE;
 540
 541                         if (isBlockTrailer(traceCurBlock)) {
 542                                 memcpy(traceCard + traceCurBlock * 16 + 6, data + 6, 4);
 543                         } else {
 544                                 memcpy(traceCard + traceCurBlock * 16, data, 16);
 545                         }
 546                         if (wantSaveToEmlFile) saveTraceCard();
 547                         return 0;
 548                 } else {
 549                         traceState = TRACE_ERROR;
 550                         return 1;
 551                 }
 552         break;
 553
 554         case TRACE_WRITE_OK:
 555                 if ((len == 1) && (data[0] == 0x0a)) {
 556                         traceState = TRACE_WRITE_DATA;
 557
 558                         return 0;
 559                 } else {
 560                         traceState = TRACE_ERROR;
 561                         return 1;
 562                 }
 563         break;
 564
 565         case TRACE_WRITE_DATA:
 566                 if (len == 18) {
 567                         traceState = TRACE_IDLE;
 568
 569                         memcpy(traceCard + traceCurBlock * 16, data, 16);
 570                         if (wantSaveToEmlFile) saveTraceCard();
 571                         return 0;
 572                 } else {
 573                         traceState = TRACE_ERROR;
 574                         return 1;
 575                 }
 576         break;
 577
 578         case TRACE_AUTH1:
 579                 if (len == 4) {
 580                         traceState = TRACE_AUTH2;
 581                         nt = bytes_to_num(data, 4);
 582                         return 0;
 583                 } else {
 584                         traceState = TRACE_ERROR;
 585                         return 1;
 586                 }
 587         break;
 588
 589         case TRACE_AUTH2:
 590                 if (len == 8) {
 591                         traceState = TRACE_AUTH_OK;
 592
 593                         nr_enc = bytes_to_num(data, 4);
 594                         ar_enc = bytes_to_num(data + 4, 4);
 595                         return 0;
 596                 } else {
 597                         traceState = TRACE_ERROR;
 598                         return 1;
 599                 }
 600         break;
 601
 602         case TRACE_AUTH_OK:
 603                 if (len ==4) {
 604                         traceState = TRACE_IDLE;
 605
 606                         at_enc = bytes_to_num(data, 4);
 607
 608                         //  decode key here)
 609                         ks2 = ar_enc ^ prng_successor(nt, 64);
 610                         ks3 = at_enc ^ prng_successor(nt, 96);
 611                         revstate = lfsr_recovery64(ks2, ks3);
 612                         lfsr_rollback_word(revstate, 0, 0);
 613                         lfsr_rollback_word(revstate, 0, 0);
 614                         lfsr_rollback_word(revstate, nr_enc, 1);
 615                         lfsr_rollback_word(revstate, uid ^ nt, 0);
 616
 617                         crypto1_get_lfsr(revstate, &key);
 618                         printf("Key: %012"llx"\n",key);
 619                         AddLogUint64(logHexFileName, "key: ", key);
 620
 621                         int blockShift = ((traceCurBlock & 0xFC) + 3) * 16;
 622                         if (isBlockEmpty((traceCurBlock & 0xFC) + 3)) memcpy(traceCard + blockShift + 6, trailerAccessBytes, 4);
 623
 624                         if (traceCurKey) {
 625                                 num_to_bytes(key, 6, traceCard + blockShift + 10);
 626                         } else {
 627                                 num_to_bytes(key, 6, traceCard + blockShift);
 628                         }
 629                         if (wantSaveToEmlFile) saveTraceCard();
 630
 631                         if (traceCrypto1) {
 632                                 crypto1_destroy(traceCrypto1);
 633                         }
 634
 635                         // set cryptosystem state
 636                         traceCrypto1 = lfsr_recovery64(ks2, ks3);
 637
 638 //      nt = crypto1_word(traceCrypto1, nt ^ uid, 1) ^ nt;
 639
 640         /*      traceCrypto1 = crypto1_create(key); // key in lfsr
 641                 crypto1_word(traceCrypto1, nt ^ uid, 0);
 642                 crypto1_word(traceCrypto1, ar, 1);
 643                 crypto1_word(traceCrypto1, 0, 0);
 644                 crypto1_word(traceCrypto1, 0, 0);*/
 645
 646                         return 0;
 647                 } else {
 648                         traceState = TRACE_ERROR;
 649                         return 1;
 650                 }
 651         break;
 652
 653         default:
 654                 traceState = TRACE_ERROR;
 655                 return 1;
 656         }
 657
 658         return 0;
 659 }
 660
 661 int tryDecryptWord(uint32_t nt, uint32_t ar_enc, uint32_t at_enc, uint8_t *data, int len){
 662         /*
 663         uint32_t nt;      // tag challenge
 664         uint32_t nr_enc;  // encrypted reader challenge
 665         uint32_t ar_enc;  // encrypted reader response
 666         uint32_t at_enc;  // encrypted tag response
 667         */
 668         struct Crypto1State *pcs = NULL;
 669
 670         ks2 = ar_enc ^ prng_successor(nt, 64);
 671         ks3 = at_enc ^ prng_successor(nt, 96);
 672
 673         PrintAndLog("Decrypting data with:");
 674         PrintAndLog("      nt: %08x",nt);
 675         PrintAndLog("  ar_enc: %08x",ar_enc);
 676         PrintAndLog("  at_enc: %08x",at_enc);
 677         PrintAndLog("\nEncrypted data: [%s]", sprint_hex(data,len) );
 678
 679         pcs = lfsr_recovery64(ks2, ks3);
 680         mf_crypto1_decrypt(pcs, data, len, FALSE);
 681         PrintAndLog("Decrypted data: [%s]", sprint_hex(data,len) );
 682         crypto1_destroy(pcs);
 683         return 0;
 684 }