cvs.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          if ((*(uint64_t*)b & 0x00ff000000ff0000) < (*(uint64_t*)a & 0x00ff000000ff0000)) return -1;
  36          if ((*(uint64_t*)b & 0x00ff000000ff0000) > (*(uint64_t*)a & 0x00ff000000ff0000)) return 1;
  37          return 0;
  38
  39         /*return
  40                 ((*(uint64_t*)b & 0x00ff000000ff0000) > (*(uint64_t*)a & 0x00ff000000ff0000))
  41                 -
  42                 ((*(uint64_t*)b & 0x00ff000000ff0000) < (*(uint64_t*)a & 0x00ff000000ff0000))
  43                 ;
  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         uid = bytes_to_num(resp.d.asBytes, 4);
 102
 103         for (i = 0; i < 2; i++) {
 104                 statelists[i].blockNo = resp.arg[2] & 0xff;
 105                 statelists[i].keyType = (resp.arg[2] >> 8) & 0xff;
 106                 statelists[i].uid = uid;
 107                 memcpy(&statelists[i].nt,  (void *)(resp.d.asBytes + 4 + i * 8 + 0), 4);
 108                 memcpy(&statelists[i].ks1, (void *)(resp.d.asBytes + 4 + i * 8 + 4), 4);
 109         }
 110
 111         // calc keys
 112         pthread_t thread_id[2];
 113
 114         // create and run worker threads
 115         for (i = 0; i < 2; i++)
 116                 pthread_create(thread_id + i, NULL, nested_worker_thread, &statelists[i]);
 117
 118         // wait for threads to terminate:
 119         for (i = 0; i < 2; i++)
 120                 pthread_join(thread_id[i], (void*)&statelists[i].head.slhead);
 121
 122         // the first 16 Bits of the cryptostate already contain part of our key.
 123         // Create the intersection of the two lists based on these 16 Bits and
 124         // roll back the cryptostate
 125         p1 = p3 = statelists[0].head.slhead;
 126         p2 = p4 = statelists[1].head.slhead;
 127
 128         while (p1 <= statelists[0].tail.sltail && p2 <= statelists[1].tail.sltail) {
 129                 if (Compare16Bits(p1, p2) == 0) {
 130
 131                         struct Crypto1State savestate, *savep = &savestate;
 132                         savestate = *p1;
 133                         while(Compare16Bits(p1, savep) == 0 && p1 <= statelists[0].tail.sltail) {
 134                                 *p3 = *p1;
 135                                 lfsr_rollback_word(p3, statelists[0].nt ^ statelists[0].uid, 0);
 136                                 p3++;
 137                                 p1++;
 138                         }
 139                         savestate = *p2;
 140                         while(Compare16Bits(p2, savep) == 0 && p2 <= statelists[1].tail.sltail) {
 141                                 *p4 = *p2;
 142                                 lfsr_rollback_word(p4, statelists[1].nt ^ statelists[1].uid, 0);
 143                                 p4++;
 144                                 p2++;
 145                         }
 146                 }
 147                 else {
 148                         while (Compare16Bits(p1, p2) == -1) p1++;
 149                         while (Compare16Bits(p1, p2) == 1) p2++;
 150                 }
 151         }
 152
 153         p3->even = 0; p3->odd = 0;
 154         p4->even = 0; p4->odd = 0;
 155         statelists[0].len = p3 - statelists[0].head.slhead;
 156         statelists[1].len = p4 - statelists[1].head.slhead;
 157         statelists[0].tail.sltail=--p3;
 158         statelists[1].tail.sltail=--p4;
 159
 160         // the statelists now contain possible keys. The key we are searching for must be in the
 161         // intersection of both lists. Create the intersection:
 162         qsort(statelists[0].head.keyhead, statelists[0].len, sizeof(uint64_t), compar_int);
 163         qsort(statelists[1].head.keyhead, statelists[1].len, sizeof(uint64_t), compar_int);
 164
 165         uint64_t *p5, *p6, *p7;
 166         p5 = p7 = statelists[0].head.keyhead;
 167         p6 = statelists[1].head.keyhead;
 168         while (p5 <= statelists[0].tail.keytail && p6 <= statelists[1].tail.keytail) {
 169                 if (compar_int(p5, p6) == 0) {
 170                         *p7++ = *p5++;
 171                         p6++;
 172                 }
 173                 else {
 174                         while (compar_int(p5, p6) == -1) p5++;
 175                         while (compar_int(p5, p6) == 1) p6++;
 176                 }
 177         }
 178         statelists[0].len = p7 - statelists[0].head.keyhead;
 179         statelists[0].tail.keytail = --p7;
 180
 181         memset(resultKey, 0, 6);
 182         uint64_t key64 = 0;
 183
 184         // The list may still contain several key candidates. Test each of them with mfCheckKeys
 185         // uint32_t max_keys = keycnt > (USB_CMD_DATA_SIZE/6) ? (USB_CMD_DATA_SIZE/6) : keycnt;
 186
 187         uint32_t numOfCandidates = statelists[0].len;
 188         if ( numOfCandidates == 0 ) goto out;
 189
 190         uint8_t *keyBlock = malloc(numOfCandidates*6);
 191         if (keyBlock == NULL) return -6;
 192
 193         for (i = 0; i < numOfCandidates; ++i){
 194                 crypto1_get_lfsr(statelists[0].head.slhead + i, &key64);
 195                 num_to_bytes(key64, 6, keyBlock + i * 6);
 196         }
 197
 198         if (!mfCheckKeys(statelists[0].blockNo, statelists[0].keyType, false, numOfCandidates, keyBlock, &key64)) {
 199                 free(statelists[0].head.slhead);
 200                 free(statelists[1].head.slhead);
 201                 free(keyBlock);
 202                 num_to_bytes(key64, 6, resultKey);
 203
 204                 PrintAndLog("UID: %08x target block:%3u key type: %c  -- Found key [%012"llx"]",
 205                         uid,
 206                         (uint16_t)resp.arg[2] & 0xff,
 207                         (resp.arg[2] >> 8) ? 'B' : 'A',
 208                         key64
 209                 );
 210                 return -5;
 211         }
 212
 213 out:
 214         PrintAndLog("UID: %08x target block:%3u key type: %c",
 215                         uid,
 216                         (uint16_t)resp.arg[2] & 0xff,
 217                         (resp.arg[2] >> 8) ? 'B' : 'A'
 218         );
 219
 220         free(statelists[0].head.slhead);
 221         free(statelists[1].head.slhead);
 222         return -4;
 223 }
 224
 225 int mfCheckKeys (uint8_t blockNo, uint8_t keyType, bool clear_trace, uint8_t keycnt, uint8_t * keyBlock, uint64_t * key){
 226
 227         *key = 0;
 228         UsbCommand c = {CMD_MIFARE_CHKKEYS, { (blockNo | (keyType<<8)), clear_trace, keycnt}};
 229         memcpy(c.d.asBytes, keyBlock, 6 * keycnt);
 230         clearCommandBuffer();
 231         SendCommand(&c);
 232         UsbCommand resp;
 233         if (!WaitForResponseTimeout(CMD_ACK,&resp, 3000)) return 1;
 234         if ((resp.arg[0] & 0xff) != 0x01) return 2;
 235         *key = bytes_to_num(resp.d.asBytes, 6);
 236         return 0;
 237 }
 238
 239 // EMULATOR
 240
 241 int mfEmlGetMem(uint8_t *data, int blockNum, int blocksCount) {
 242         UsbCommand c = {CMD_MIFARE_EML_MEMGET, {blockNum, blocksCount, 0}};
 243         clearCommandBuffer();
 244         SendCommand(&c);
 245         UsbCommand resp;
 246         if (!WaitForResponseTimeout(CMD_ACK,&resp,1500)) return 1;
 247         memcpy(data, resp.d.asBytes, blocksCount * 16);
 248         return 0;
 249 }
 250
 251 int mfEmlSetMem(uint8_t *data, int blockNum, int blocksCount) {
 252         return mfEmlSetMem_xt(data, blockNum, blocksCount, 16);
 253 }
 254
 255 int mfEmlSetMem_xt(uint8_t *data, int blockNum, int blocksCount, int blockBtWidth) {
 256         UsbCommand c = {CMD_MIFARE_EML_MEMSET, {blockNum, blocksCount, blockBtWidth}};
 257         memcpy(c.d.asBytes, data, blocksCount * blockBtWidth);
 258
 259         clearCommandBuffer();
 260         SendCommand(&c);
 261         return 0;
 262 }
 263
 264 // "MAGIC" CARD
 265
 266 int mfCSetUID(uint8_t *uid, uint8_t *atqa, uint8_t *sak, uint8_t *oldUID, uint8_t wipecard) {
 267
 268         uint8_t params = MAGIC_SINGLE;
 269         uint8_t block0[16];
 270         memset(block0, 0x00, sizeof(block0));
 271
 272         int old = mfCGetBlock(0, block0, params);
 273         if (old == 0)
 274                 PrintAndLog("old block 0:  %s", sprint_hex(block0, sizeof(block0)));
 275         else
 276                 PrintAndLog("Couldn't get old data. Will write over the last bytes of Block 0.");
 277
 278         // fill in the new values
 279         // UID
 280         memcpy(block0, uid, 4);
 281         // Mifare UID BCC
 282         block0[4] = block0[0]^block0[1]^block0[2]^block0[3];
 283         // mifare classic SAK(byte 5) and ATQA(byte 6 and 7, reversed)
 284         if ( sak != NULL )
 285                 block0[5]=sak[0];
 286
 287         if ( atqa != NULL ) {
 288                 block0[6]=atqa[1];
 289                 block0[7]=atqa[0];
 290         }
 291         PrintAndLog("new block 0:  %s", sprint_hex(block0,16));
 292
 293         if ( wipecard )          params |= MAGIC_WIPE;
 294         if ( oldUID == NULL) params |= MAGIC_UID;
 295
 296         return mfCSetBlock(0, block0, oldUID, params);
 297 }
 298
 299 int mfCSetBlock(uint8_t blockNo, uint8_t *data, uint8_t *uid, uint8_t params) {
 300
 301         uint8_t isOK = 0;
 302         UsbCommand c = {CMD_MIFARE_CSETBLOCK, {params, blockNo, 0}};
 303         memcpy(c.d.asBytes, data, 16);
 304         clearCommandBuffer();
 305         SendCommand(&c);
 306         UsbCommand resp;
 307         if (WaitForResponseTimeout(CMD_ACK, &resp, 1500)) {
 308                 isOK  = resp.arg[0] & 0xff;
 309                 if (uid != NULL)
 310                         memcpy(uid, resp.d.asBytes, 4);
 311                 if (!isOK)
 312                         return 2;
 313         } else {
 314                 PrintAndLog("Command execute timeout");
 315                 return 1;
 316         }
 317         return 0;
 318 }
 319
 320 int mfCGetBlock(uint8_t blockNo, uint8_t *data, uint8_t params) {
 321         uint8_t isOK = 0;
 322         UsbCommand c = {CMD_MIFARE_CGETBLOCK, {params, blockNo, 0}};
 323         clearCommandBuffer();
 324         SendCommand(&c);
 325         UsbCommand resp;
 326         if (WaitForResponseTimeout(CMD_ACK,&resp,1500)) {
 327                 isOK  = resp.arg[0] & 0xff;
 328                 memcpy(data, resp.d.asBytes, 16);
 329                 if (!isOK) return 2;
 330         } else {
 331                 PrintAndLog("Command execute timeout");
 332                 return 1;
 333         }
 334         return 0;
 335 }
 336
 337 // SNIFFER
 338
 339 // constants
 340 static uint8_t trailerAccessBytes[4] = {0x08, 0x77, 0x8F, 0x00};
 341
 342 // variables
 343 char logHexFileName[FILE_PATH_SIZE] = {0x00};
 344 static uint8_t traceCard[4096] = {0x00};
 345 static char traceFileName[FILE_PATH_SIZE] = {0x00};
 346 static int traceState = TRACE_IDLE;
 347 static uint8_t traceCurBlock = 0;
 348 static uint8_t traceCurKey = 0;
 349
 350 struct Crypto1State *traceCrypto1 = NULL;
 351
 352 struct Crypto1State *revstate = NULL;
 353
 354 uint64_t key = 0;
 355 uint32_t ks2 = 0;
 356 uint32_t ks3 = 0;
 357
 358 uint32_t uid = 0;     // serial number
 359 uint32_t nt =0;      // tag challenge
 360 uint32_t nr_enc =0;  // encrypted reader challenge
 361 uint32_t ar_enc =0;  // encrypted reader response
 362 uint32_t at_enc =0;  // encrypted tag response
 363
 364 int isTraceCardEmpty(void) {
 365         return ((traceCard[0] == 0) && (traceCard[1] == 0) && (traceCard[2] == 0) && (traceCard[3] == 0));
 366 }
 367
 368 int isBlockEmpty(int blockN) {
 369         for (int i = 0; i < 16; i++)
 370                 if (traceCard[blockN * 16 + i] != 0) return 0;
 371
 372         return 1;
 373 }
 374
 375 int isBlockTrailer(int blockN) {
 376         return ((blockN & 0x03) == 0x03);
 377 }
 378
 379 int loadTraceCard(uint8_t *tuid) {
 380         FILE * f;
 381         char buf[64] = {0x00};
 382         uint8_t buf8[64] = {0x00};
 383         int i, blockNum;
 384
 385         if (!isTraceCardEmpty())
 386                 saveTraceCard();
 387
 388         memset(traceCard, 0x00, 4096);
 389         memcpy(traceCard, tuid + 3, 4);
 390
 391         FillFileNameByUID(traceFileName, tuid, ".eml", 7);
 392
 393         f = fopen(traceFileName, "r");
 394         if (!f) return 1;
 395
 396         blockNum = 0;
 397
 398         while(!feof(f)){
 399
 400                 memset(buf, 0, sizeof(buf));
 401                 if (fgets(buf, sizeof(buf), f) == NULL) {
 402                         PrintAndLog("File reading error.");
 403                         fclose(f);
 404                         return 2;
 405                 }
 406
 407                 if (strlen(buf) < 32){
 408                         if (feof(f)) break;
 409                         PrintAndLog("File content error. Block data must include 32 HEX symbols");
 410                         fclose(f);
 411                         return 2;
 412                 }
 413                 for (i = 0; i < 32; i += 2)
 414                         sscanf(&buf[i], "%02x", (unsigned int *)&buf8[i / 2]);
 415
 416                 memcpy(traceCard + blockNum * 16, buf8, 16);
 417
 418                 blockNum++;
 419         }
 420         fclose(f);
 421
 422         return 0;
 423 }
 424
 425 int saveTraceCard(void) {
 426         FILE * f;
 427
 428         if ((!strlen(traceFileName)) || (isTraceCardEmpty())) return 0;
 429
 430         f = fopen(traceFileName, "w+");
 431         if ( !f ) return 1;
 432
 433         for (int i = 0; i < 64; i++) {  // blocks
 434                 for (int j = 0; j < 16; j++)  // bytes
 435                         fprintf(f, "%02x", *(traceCard + i * 16 + j));
 436                 fprintf(f,"\n");
 437         }
 438         fclose(f);
 439         return 0;
 440 }
 441
 442 int mfTraceInit(uint8_t *tuid, uint8_t *atqa, uint8_t sak, bool wantSaveToEmlFile) {
 443
 444         if (traceCrypto1)
 445                 crypto1_destroy(traceCrypto1);
 446
 447         traceCrypto1 = NULL;
 448
 449         if (wantSaveToEmlFile)
 450                 loadTraceCard(tuid);
 451
 452         traceCard[4] = traceCard[0] ^ traceCard[1] ^ traceCard[2] ^ traceCard[3];
 453         traceCard[5] = sak;
 454         memcpy(&traceCard[6], atqa, 2);
 455         traceCurBlock = 0;
 456         uid = bytes_to_num(tuid + 3, 4);
 457
 458         traceState = TRACE_IDLE;
 459
 460         return 0;
 461 }
 462
 463 void mf_crypto1_decrypt(struct Crypto1State *pcs, uint8_t *data, int len, bool isEncrypted){
 464         uint8_t bt = 0;
 465         int i;
 466
 467         if (len != 1) {
 468                 for (i = 0; i < len; i++)
 469                         data[i] = crypto1_byte(pcs, 0x00, isEncrypted) ^ data[i];
 470         } else {
 471                 bt = 0;
 472                 bt |= (crypto1_bit(pcs, 0, isEncrypted) ^ BIT(data[0], 0)) << 0;
 473                 bt |= (crypto1_bit(pcs, 0, isEncrypted) ^ BIT(data[0], 1)) << 1;
 474                 bt |= (crypto1_bit(pcs, 0, isEncrypted) ^ BIT(data[0], 2)) << 2;
 475                 bt |= (crypto1_bit(pcs, 0, isEncrypted) ^ BIT(data[0], 3)) << 3;
 476                 data[0] = bt;
 477         }
 478         return;
 479 }
 480
 481 int mfTraceDecode(uint8_t *data_src, int len, bool wantSaveToEmlFile) {
 482
 483         uint8_t data[64];
 484
 485         if (traceState == TRACE_ERROR) return 1;
 486
 487         if (len > 64) {
 488                 traceState = TRACE_ERROR;
 489                 return 1;
 490         }
 491
 492         memcpy(data, data_src, len);
 493         if ((traceCrypto1) && ((traceState == TRACE_IDLE) || (traceState > TRACE_AUTH_OK))) {
 494                 mf_crypto1_decrypt(traceCrypto1, data, len, 0);
 495                 PrintAndLog("dec> %s", sprint_hex(data, len));
 496                 AddLogHex(logHexFileName, "dec> ", data, len);
 497         }
 498
 499         switch (traceState) {
 500         case TRACE_IDLE:
 501                 // check packet crc16!
 502                 if ((len >= 4) && (!CheckCrc14443(CRC_14443_A, data, len))) {
 503                         PrintAndLog("dec> CRC ERROR!!!");
 504                         AddLogLine(logHexFileName, "dec> ", "CRC ERROR!!!");
 505                         traceState = TRACE_ERROR;  // do not decrypt the next commands
 506                         return 1;
 507                 }
 508
 509                 // AUTHENTICATION
 510                 if ((len == 4) && ((data[0] == 0x60) || (data[0] == 0x61))) {
 511                         traceState = TRACE_AUTH1;
 512                         traceCurBlock = data[1];
 513                         traceCurKey = data[0] == 60 ? 1:0;
 514                         return 0;
 515                 }
 516
 517                 // READ
 518                 if ((len ==4) && ((data[0] == 0x30))) {
 519                         traceState = TRACE_READ_DATA;
 520                         traceCurBlock = data[1];
 521                         return 0;
 522                 }
 523
 524                 // WRITE
 525                 if ((len ==4) && ((data[0] == 0xA0))) {
 526                         traceState = TRACE_WRITE_OK;
 527                         traceCurBlock = data[1];
 528                         return 0;
 529                 }
 530
 531                 // HALT
 532                 if ((len ==4) && ((data[0] == 0x50) && (data[1] == 0x00))) {
 533                         traceState = TRACE_ERROR;  // do not decrypt the next commands
 534                         return 0;
 535                 }
 536
 537                 return 0;
 538         break;
 539
 540         case TRACE_READ_DATA:
 541                 if (len == 18) {
 542                         traceState = TRACE_IDLE;
 543
 544                         if (isBlockTrailer(traceCurBlock)) {
 545                                 memcpy(traceCard + traceCurBlock * 16 + 6, data + 6, 4);
 546                         } else {
 547                                 memcpy(traceCard + traceCurBlock * 16, data, 16);
 548                         }
 549                         if (wantSaveToEmlFile) saveTraceCard();
 550                         return 0;
 551                 } else {
 552                         traceState = TRACE_ERROR;
 553                         return 1;
 554                 }
 555         break;
 556
 557         case TRACE_WRITE_OK:
 558                 if ((len == 1) && (data[0] == 0x0a)) {
 559                         traceState = TRACE_WRITE_DATA;
 560
 561                         return 0;
 562                 } else {
 563                         traceState = TRACE_ERROR;
 564                         return 1;
 565                 }
 566         break;
 567
 568         case TRACE_WRITE_DATA:
 569                 if (len == 18) {
 570                         traceState = TRACE_IDLE;
 571
 572                         memcpy(traceCard + traceCurBlock * 16, data, 16);
 573                         if (wantSaveToEmlFile) saveTraceCard();
 574                         return 0;
 575                 } else {
 576                         traceState = TRACE_ERROR;
 577                         return 1;
 578                 }
 579         break;
 580
 581         case TRACE_AUTH1:
 582                 if (len == 4) {
 583                         traceState = TRACE_AUTH2;
 584                         nt = bytes_to_num(data, 4);
 585                         return 0;
 586                 } else {
 587                         traceState = TRACE_ERROR;
 588                         return 1;
 589                 }
 590         break;
 591
 592         case TRACE_AUTH2:
 593                 if (len == 8) {
 594                         traceState = TRACE_AUTH_OK;
 595
 596                         nr_enc = bytes_to_num(data, 4);
 597                         ar_enc = bytes_to_num(data + 4, 4);
 598                         return 0;
 599                 } else {
 600                         traceState = TRACE_ERROR;
 601                         return 1;
 602                 }
 603         break;
 604
 605         case TRACE_AUTH_OK:
 606                 if (len ==4) {
 607                         traceState = TRACE_IDLE;
 608
 609                         at_enc = bytes_to_num(data, 4);
 610
 611                         //  decode key here)
 612                         ks2 = ar_enc ^ prng_successor(nt, 64);
 613                         ks3 = at_enc ^ prng_successor(nt, 96);
 614                         revstate = lfsr_recovery64(ks2, ks3);
 615                         lfsr_rollback_word(revstate, 0, 0);
 616                         lfsr_rollback_word(revstate, 0, 0);
 617                         lfsr_rollback_word(revstate, nr_enc, 1);
 618                         lfsr_rollback_word(revstate, uid ^ nt, 0);
 619
 620                         crypto1_get_lfsr(revstate, &key);
 621                         printf("Key: %012"llx"\n",key);
 622                         AddLogUint64(logHexFileName, "key: ", key);
 623
 624                         int blockShift = ((traceCurBlock & 0xFC) + 3) * 16;
 625                         if (isBlockEmpty((traceCurBlock & 0xFC) + 3)) memcpy(traceCard + blockShift + 6, trailerAccessBytes, 4);
 626
 627                         if (traceCurKey) {
 628                                 num_to_bytes(key, 6, traceCard + blockShift + 10);
 629                         } else {
 630                                 num_to_bytes(key, 6, traceCard + blockShift);
 631                         }
 632                         if (wantSaveToEmlFile) saveTraceCard();
 633
 634                         if (traceCrypto1) {
 635                                 crypto1_destroy(traceCrypto1);
 636                         }
 637
 638                         // set cryptosystem state
 639                         traceCrypto1 = lfsr_recovery64(ks2, ks3);
 640
 641 //      nt = crypto1_word(traceCrypto1, nt ^ uid, 1) ^ nt;
 642
 643         /*      traceCrypto1 = crypto1_create(key); // key in lfsr
 644                 crypto1_word(traceCrypto1, nt ^ uid, 0);
 645                 crypto1_word(traceCrypto1, ar, 1);
 646                 crypto1_word(traceCrypto1, 0, 0);
 647                 crypto1_word(traceCrypto1, 0, 0);*/
 648
 649                         return 0;
 650                 } else {
 651                         traceState = TRACE_ERROR;
 652                         return 1;
 653                 }
 654         break;
 655
 656         default:
 657                 traceState = TRACE_ERROR;
 658                 return 1;
 659         }
 660
 661         return 0;
 662 }
 663
 664 int tryDecryptWord(uint32_t nt, uint32_t ar_enc, uint32_t at_enc, uint8_t *data, int len){
 665         /*
 666         uint32_t nt;      // tag challenge
 667         uint32_t nr_enc;  // encrypted reader challenge
 668         uint32_t ar_enc;  // encrypted reader response
 669         uint32_t at_enc;  // encrypted tag response
 670         */
 671         struct Crypto1State *pcs = NULL;
 672
 673         ks2 = ar_enc ^ prng_successor(nt, 64);
 674         ks3 = at_enc ^ prng_successor(nt, 96);
 675
 676         PrintAndLog("Decrypting data with:");
 677         PrintAndLog("      nt: %08x",nt);
 678         PrintAndLog("  ar_enc: %08x",ar_enc);
 679         PrintAndLog("  at_enc: %08x",at_enc);
 680         PrintAndLog("\nEncrypted data: [%s]", sprint_hex(data,len) );
 681
 682         pcs = lfsr_recovery64(ks2, ks3);
 683         mf_crypto1_decrypt(pcs, data, len, FALSE);
 684         PrintAndLog("Decrypted data: [%s]", sprint_hex(data,len) );
 685         crypto1_destroy(pcs);
 686         return 0;
 687 }