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 #include <time.h>
  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 1;
  27         if (*(uint64_t*)b < *(uint64_t*)a) return -1;
  28         return 0;
  29
  30         //return (*(uint64_t*)b > *(uint64_t*)a) - (*(uint64_t*)b < *(uint64_t*)a);
  31 }
  32
  33 // Compare 16 Bits out of cryptostate
  34 int Compare16Bits(const void * a, const void * b) {
  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         clock_t t1 = clock();
  70         struct Crypto1State *p1;
  71         StateList_t *statelist = arg;
  72
  73         statelist->head.slhead = lfsr_recovery32(statelist->ks1, statelist->nt ^ statelist->uid);
  74
  75         for (p1 = statelist->head.slhead; *(uint64_t *)p1 != 0; p1++);
  76
  77         statelist->len = p1 - statelist->head.slhead;
  78         statelist->tail.sltail = --p1;
  79         qsort(statelist->head.slhead, statelist->len, sizeof(uint64_t), Compare16Bits);
  80
  81
  82         t1 = clock() - t1;
  83         printf("lfsr_recovery32 takes %.0f ticks \n", (float)t1);
  84         return statelist->head.slhead;
  85 }
  86
  87 int mfnested(uint8_t blockNo, uint8_t keyType, uint8_t * key, uint8_t trgBlockNo, uint8_t trgKeyType, uint8_t * resultKey, bool calibrate)
  88 {
  89         uint16_t i;
  90         uint32_t uid;
  91         UsbCommand resp;
  92         StateList_t statelists[2];
  93         struct Crypto1State *p1, *p2, *p3, *p4;
  94
  95         UsbCommand c = {CMD_MIFARE_NESTED, {blockNo + keyType * 0x100, trgBlockNo + trgKeyType * 0x100, calibrate}};
  96         memcpy(c.d.asBytes, key, 6);
  97         clearCommandBuffer();
  98         SendCommand(&c);
  99         if (!WaitForResponseTimeout(CMD_ACK, &resp, 1500)) return -1;
 100
 101         // error during nested
 102         if (resp.arg[0]) return resp.arg[0];
 103
 104         memcpy(&uid, resp.d.asBytes, 4);
 105
 106         for (i = 0; i < 2; i++) {
 107                 statelists[i].blockNo = resp.arg[2] & 0xff;
 108                 statelists[i].keyType = (resp.arg[2] >> 8) & 0xff;
 109                 statelists[i].uid = uid;
 110                 memcpy(&statelists[i].nt,  (void *)(resp.d.asBytes + 4 + i * 8 + 0), 4);
 111                 memcpy(&statelists[i].ks1, (void *)(resp.d.asBytes + 4 + i * 8 + 4), 4);
 112         }
 113
 114         // calc keys
 115         pthread_t thread_id[2];
 116
 117         // create and run worker threads
 118         for (i = 0; i < 2; i++)
 119                 pthread_create(thread_id + i, NULL, nested_worker_thread, &statelists[i]);
 120
 121         // wait for threads to terminate:
 122         for (i = 0; i < 2; i++)
 123                 pthread_join(thread_id[i], (void*)&statelists[i].head.slhead);
 124
 125         // the first 16 Bits of the cryptostate already contain part of our key.
 126         // Create the intersection of the two lists based on these 16 Bits and
 127         // roll back the cryptostate
 128         p1 = p3 = statelists[0].head.slhead;
 129         p2 = p4 = statelists[1].head.slhead;
 130
 131         while (p1 <= statelists[0].tail.sltail && p2 <= statelists[1].tail.sltail) {
 132                 if (Compare16Bits(p1, p2) == 0) {
 133
 134                         struct Crypto1State savestate, *savep = &savestate;
 135                         savestate = *p1;
 136                         while(Compare16Bits(p1, savep) == 0 && p1 <= statelists[0].tail.sltail) {
 137                                 *p3 = *p1;
 138                                 lfsr_rollback_word(p3, statelists[0].nt ^ statelists[0].uid, 0);
 139                                 p3++;
 140                                 p1++;
 141                         }
 142                         savestate = *p2;
 143                         while(Compare16Bits(p2, savep) == 0 && p2 <= statelists[1].tail.sltail) {
 144                                 *p4 = *p2;
 145                                 lfsr_rollback_word(p4, statelists[1].nt ^ statelists[1].uid, 0);
 146                                 p4++;
 147                                 p2++;
 148                         }
 149                 }
 150                 else {
 151                         while (Compare16Bits(p1, p2) == -1) p1++;
 152                         while (Compare16Bits(p1, p2) == 1) p2++;
 153                 }
 154         }
 155
 156         p3->even = 0; p3->odd = 0;
 157         p4->even = 0; p4->odd = 0;
 158         statelists[0].len = p3 - statelists[0].head.slhead;
 159         statelists[1].len = p4 - statelists[1].head.slhead;
 160         statelists[0].tail.sltail=--p3;
 161         statelists[1].tail.sltail=--p4;
 162
 163         // the statelists now contain possible keys. The key we are searching for must be in the
 164         // intersection of both lists. Create the intersection:
 165         qsort(statelists[0].head.keyhead, statelists[0].len, sizeof(uint64_t), compar_int);
 166         qsort(statelists[1].head.keyhead, statelists[1].len, sizeof(uint64_t), compar_int);
 167
 168         uint64_t *p5, *p6, *p7;
 169         p5 = p7 = statelists[0].head.keyhead;
 170         p6 = statelists[1].head.keyhead;
 171
 172         while (p5 <= statelists[0].tail.keytail && p6 <= statelists[1].tail.keytail) {
 173                 if (compar_int(p5, p6) == 0) {
 174                         *p7++ = *p5++;
 175                         p6++;
 176                 }
 177                 else {
 178                         while (compar_int(p5, p6) == -1) p5++;
 179                         while (compar_int(p5, p6) == 1) p6++;
 180                 }
 181         }
 182         statelists[0].len = p7 - statelists[0].head.keyhead;
 183         statelists[0].tail.keytail = --p7;
 184
 185         uint32_t numOfCandidates = statelists[0].len;
 186         if ( numOfCandidates == 0 ) goto out;
 187
 188         memset(resultKey, 0, 6);
 189         uint64_t key64 = 0;
 190
 191         // The list may still contain several key candidates. Test each of them with mfCheckKeys
 192         // uint32_t max_keys = keycnt > (USB_CMD_DATA_SIZE/6) ? (USB_CMD_DATA_SIZE/6) : keycnt;
 193         uint8_t keyBlock[USB_CMD_DATA_SIZE] = {0x00};
 194
 195         clock_t t1 = clock();
 196         for (i = 0; i < numOfCandidates; ++i){
 197                 crypto1_get_lfsr(statelists[0].head.slhead + i, &key64);
 198                 num_to_bytes(key64, 6, keyBlock + i * 6);
 199         }
 200
 201         if (!mfCheckKeys(statelists[0].blockNo, statelists[0].keyType, false, numOfCandidates, keyBlock, &key64)) {
 202                 free(statelists[0].head.slhead);
 203                 free(statelists[1].head.slhead);
 204                 num_to_bytes(key64, 6, resultKey);
 205
 206                 t1 = clock() - t1;
 207                 printf("Check candidates takes %.0f ticks \n", (float)t1);
 208
 209                 PrintAndLog("UID: %08x target block:%3u key type: %c  -- Found key [%012"llx"]",
 210                         uid,
 211                         (uint16_t)resp.arg[2] & 0xff,
 212                         (resp.arg[2] >> 8) ? 'B' : 'A',
 213                         key64
 214                 );
 215                 return -5;
 216         }
 217
 218 out:
 219         PrintAndLog("UID: %08x target block:%3u key type: %c",
 220                         uid,
 221                         (uint16_t)resp.arg[2] & 0xff,
 222                         (resp.arg[2] >> 8) ? 'B' : 'A'
 223         );
 224
 225         free(statelists[0].head.slhead);
 226         free(statelists[1].head.slhead);
 227         return -4;
 228 }
 229
 230 int mfCheckKeys (uint8_t blockNo, uint8_t keyType, bool clear_trace, uint8_t keycnt, uint8_t * keyBlock, uint64_t * key){
 231
 232         *key = 0;
 233         UsbCommand c = {CMD_MIFARE_CHKKEYS, { (blockNo | (keyType<<8)), clear_trace, keycnt}};
 234         memcpy(c.d.asBytes, keyBlock, 6 * keycnt);
 235         clearCommandBuffer();
 236         SendCommand(&c);
 237         UsbCommand resp;
 238         if (!WaitForResponseTimeout(CMD_ACK,&resp, 3000)) return 1;
 239         if ((resp.arg[0] & 0xff) != 0x01) return 2;
 240         *key = bytes_to_num(resp.d.asBytes, 6);
 241         return 0;
 242 }
 243
 244 // EMULATOR
 245
 246 int mfEmlGetMem(uint8_t *data, int blockNum, int blocksCount) {
 247         UsbCommand c = {CMD_MIFARE_EML_MEMGET, {blockNum, blocksCount, 0}};
 248         clearCommandBuffer();
 249         SendCommand(&c);
 250         UsbCommand resp;
 251         if (!WaitForResponseTimeout(CMD_ACK,&resp,1500)) return 1;
 252         memcpy(data, resp.d.asBytes, blocksCount * 16);
 253         return 0;
 254 }
 255
 256 int mfEmlSetMem(uint8_t *data, int blockNum, int blocksCount) {
 257         return mfEmlSetMem_xt(data, blockNum, blocksCount, 16);
 258 }
 259
 260 int mfEmlSetMem_xt(uint8_t *data, int blockNum, int blocksCount, int blockBtWidth) {
 261         UsbCommand c = {CMD_MIFARE_EML_MEMSET, {blockNum, blocksCount, blockBtWidth}};
 262         memcpy(c.d.asBytes, data, blocksCount * blockBtWidth);
 263
 264         clearCommandBuffer();
 265         SendCommand(&c);
 266         return 0;
 267 }
 268
 269 // "MAGIC" CARD
 270
 271 int mfCSetUID(uint8_t *uid, uint8_t *atqa, uint8_t *sak, uint8_t *oldUID, uint8_t wipecard) {
 272
 273         uint8_t params = MAGIC_SINGLE;
 274         uint8_t block0[16];
 275         memset(block0, 0x00, sizeof(block0));
 276
 277         int old = mfCGetBlock(0, block0, params);
 278         if (old == 0)
 279                 PrintAndLog("old block 0:  %s", sprint_hex(block0, sizeof(block0)));
 280         else
 281                 PrintAndLog("Couldn't get old data. Will write over the last bytes of Block 0.");
 282
 283         // fill in the new values
 284         // UID
 285         memcpy(block0, uid, 4);
 286         // Mifare UID BCC
 287         block0[4] = block0[0]^block0[1]^block0[2]^block0[3];
 288         // mifare classic SAK(byte 5) and ATQA(byte 6 and 7, reversed)
 289         if ( sak != NULL )
 290                 block0[5]=sak[0];
 291
 292         if ( atqa != NULL ) {
 293                 block0[6]=atqa[1];
 294                 block0[7]=atqa[0];
 295         }
 296         PrintAndLog("new block 0:  %s", sprint_hex(block0,16));
 297
 298         if ( wipecard )          params |= MAGIC_WIPE;
 299         if ( oldUID == NULL) params |= MAGIC_UID;
 300
 301         return mfCSetBlock(0, block0, oldUID, params);
 302 }
 303
 304 int mfCSetBlock(uint8_t blockNo, uint8_t *data, uint8_t *uid, uint8_t params) {
 305
 306         uint8_t isOK = 0;
 307         UsbCommand c = {CMD_MIFARE_CSETBLOCK, {params, blockNo, 0}};
 308         memcpy(c.d.asBytes, data, 16);
 309         clearCommandBuffer();
 310         SendCommand(&c);
 311         UsbCommand resp;
 312         if (WaitForResponseTimeout(CMD_ACK, &resp, 1500)) {
 313                 isOK  = resp.arg[0] & 0xff;
 314                 if (uid != NULL)
 315                         memcpy(uid, resp.d.asBytes, 4);
 316                 if (!isOK)
 317                         return 2;
 318         } else {
 319                 PrintAndLog("Command execute timeout");
 320                 return 1;
 321         }
 322         return 0;
 323 }
 324
 325 int mfCGetBlock(uint8_t blockNo, uint8_t *data, uint8_t params) {
 326         uint8_t isOK = 0;
 327         UsbCommand c = {CMD_MIFARE_CGETBLOCK, {params, blockNo, 0}};
 328         clearCommandBuffer();
 329         SendCommand(&c);
 330         UsbCommand resp;
 331         if (WaitForResponseTimeout(CMD_ACK,&resp,1500)) {
 332                 isOK  = resp.arg[0] & 0xff;
 333                 memcpy(data, resp.d.asBytes, 16);
 334                 if (!isOK) return 2;
 335         } else {
 336                 PrintAndLog("Command execute timeout");
 337                 return 1;
 338         }
 339         return 0;
 340 }
 341
 342 // SNIFFER
 343
 344 // constants
 345 static uint8_t trailerAccessBytes[4] = {0x08, 0x77, 0x8F, 0x00};
 346
 347 // variables
 348 char logHexFileName[FILE_PATH_SIZE] = {0x00};
 349 static uint8_t traceCard[4096] = {0x00};
 350 static char traceFileName[FILE_PATH_SIZE] = {0x00};
 351 static int traceState = TRACE_IDLE;
 352 static uint8_t traceCurBlock = 0;
 353 static uint8_t traceCurKey = 0;
 354
 355 struct Crypto1State *traceCrypto1 = NULL;
 356
 357 struct Crypto1State *revstate = NULL;
 358
 359 uint64_t key = 0;
 360 uint32_t ks2 = 0;
 361 uint32_t ks3 = 0;
 362
 363 uint32_t uid = 0;     // serial number
 364 uint32_t nt =0;      // tag challenge
 365 uint32_t nr_enc =0;  // encrypted reader challenge
 366 uint32_t ar_enc =0;  // encrypted reader response
 367 uint32_t at_enc =0;  // encrypted tag response
 368
 369 int isTraceCardEmpty(void) {
 370         return ((traceCard[0] == 0) && (traceCard[1] == 0) && (traceCard[2] == 0) && (traceCard[3] == 0));
 371 }
 372
 373 int isBlockEmpty(int blockN) {
 374         for (int i = 0; i < 16; i++)
 375                 if (traceCard[blockN * 16 + i] != 0) return 0;
 376
 377         return 1;
 378 }
 379
 380 int isBlockTrailer(int blockN) {
 381         return ((blockN & 0x03) == 0x03);
 382 }
 383
 384 int loadTraceCard(uint8_t *tuid) {
 385         FILE * f;
 386         char buf[64] = {0x00};
 387         uint8_t buf8[64] = {0x00};
 388         int i, blockNum;
 389
 390         if (!isTraceCardEmpty())
 391                 saveTraceCard();
 392
 393         memset(traceCard, 0x00, 4096);
 394         memcpy(traceCard, tuid + 3, 4);
 395
 396         FillFileNameByUID(traceFileName, tuid, ".eml", 7);
 397
 398         f = fopen(traceFileName, "r");
 399         if (!f) return 1;
 400
 401         blockNum = 0;
 402
 403         while(!feof(f)){
 404
 405                 memset(buf, 0, sizeof(buf));
 406                 if (fgets(buf, sizeof(buf), f) == NULL) {
 407                         PrintAndLog("File reading error.");
 408                         fclose(f);
 409                         return 2;
 410                 }
 411
 412                 if (strlen(buf) < 32){
 413                         if (feof(f)) break;
 414                         PrintAndLog("File content error. Block data must include 32 HEX symbols");
 415                         fclose(f);
 416                         return 2;
 417                 }
 418                 for (i = 0; i < 32; i += 2)
 419                         sscanf(&buf[i], "%02x", (unsigned int *)&buf8[i / 2]);
 420
 421                 memcpy(traceCard + blockNum * 16, buf8, 16);
 422
 423                 blockNum++;
 424         }
 425         fclose(f);
 426
 427         return 0;
 428 }
 429
 430 int saveTraceCard(void) {
 431         FILE * f;
 432
 433         if ((!strlen(traceFileName)) || (isTraceCardEmpty())) return 0;
 434
 435         f = fopen(traceFileName, "w+");
 436         if ( !f ) return 1;
 437
 438         for (int i = 0; i < 64; i++) {  // blocks
 439                 for (int j = 0; j < 16; j++)  // bytes
 440                         fprintf(f, "%02x", *(traceCard + i * 16 + j));
 441                 fprintf(f,"\n");
 442         }
 443         fclose(f);
 444         return 0;
 445 }
 446
 447 int mfTraceInit(uint8_t *tuid, uint8_t *atqa, uint8_t sak, bool wantSaveToEmlFile) {
 448
 449         if (traceCrypto1)
 450                 crypto1_destroy(traceCrypto1);
 451
 452         traceCrypto1 = NULL;
 453
 454         if (wantSaveToEmlFile)
 455                 loadTraceCard(tuid);
 456
 457         traceCard[4] = traceCard[0] ^ traceCard[1] ^ traceCard[2] ^ traceCard[3];
 458         traceCard[5] = sak;
 459         memcpy(&traceCard[6], atqa, 2);
 460         traceCurBlock = 0;
 461         uid = bytes_to_num(tuid + 3, 4);
 462
 463         traceState = TRACE_IDLE;
 464
 465         return 0;
 466 }
 467
 468 void mf_crypto1_decrypt(struct Crypto1State *pcs, uint8_t *data, int len, bool isEncrypted){
 469         uint8_t bt = 0;
 470         int i;
 471
 472         if (len != 1) {
 473                 for (i = 0; i < len; i++)
 474                         data[i] = crypto1_byte(pcs, 0x00, isEncrypted) ^ data[i];
 475         } else {
 476                 bt = 0;
 477                 bt |= (crypto1_bit(pcs, 0, isEncrypted) ^ BIT(data[0], 0)) << 0;
 478                 bt |= (crypto1_bit(pcs, 0, isEncrypted) ^ BIT(data[0], 1)) << 1;
 479                 bt |= (crypto1_bit(pcs, 0, isEncrypted) ^ BIT(data[0], 2)) << 2;
 480                 bt |= (crypto1_bit(pcs, 0, isEncrypted) ^ BIT(data[0], 3)) << 3;
 481                 data[0] = bt;
 482         }
 483         return;
 484 }
 485
 486 int mfTraceDecode(uint8_t *data_src, int len, bool wantSaveToEmlFile) {
 487
 488         uint8_t data[64];
 489
 490         if (traceState == TRACE_ERROR) return 1;
 491
 492         if (len > 64) {
 493                 traceState = TRACE_ERROR;
 494                 return 1;
 495         }
 496
 497         memcpy(data, data_src, len);
 498         if ((traceCrypto1) && ((traceState == TRACE_IDLE) || (traceState > TRACE_AUTH_OK))) {
 499                 mf_crypto1_decrypt(traceCrypto1, data, len, 0);
 500                 PrintAndLog("dec> %s", sprint_hex(data, len));
 501                 AddLogHex(logHexFileName, "dec> ", data, len);
 502         }
 503
 504         switch (traceState) {
 505         case TRACE_IDLE:
 506                 // check packet crc16!
 507                 if ((len >= 4) && (!CheckCrc14443(CRC_14443_A, data, len))) {
 508                         PrintAndLog("dec> CRC ERROR!!!");
 509                         AddLogLine(logHexFileName, "dec> ", "CRC ERROR!!!");
 510                         traceState = TRACE_ERROR;  // do not decrypt the next commands
 511                         return 1;
 512                 }
 513
 514                 // AUTHENTICATION
 515                 if ((len == 4) && ((data[0] == 0x60) || (data[0] == 0x61))) {
 516                         traceState = TRACE_AUTH1;
 517                         traceCurBlock = data[1];
 518                         traceCurKey = data[0] == 60 ? 1:0;
 519                         return 0;
 520                 }
 521
 522                 // READ
 523                 if ((len ==4) && ((data[0] == 0x30))) {
 524                         traceState = TRACE_READ_DATA;
 525                         traceCurBlock = data[1];
 526                         return 0;
 527                 }
 528
 529                 // WRITE
 530                 if ((len ==4) && ((data[0] == 0xA0))) {
 531                         traceState = TRACE_WRITE_OK;
 532                         traceCurBlock = data[1];
 533                         return 0;
 534                 }
 535
 536                 // HALT
 537                 if ((len ==4) && ((data[0] == 0x50) && (data[1] == 0x00))) {
 538                         traceState = TRACE_ERROR;  // do not decrypt the next commands
 539                         return 0;
 540                 }
 541
 542                 return 0;
 543         break;
 544
 545         case TRACE_READ_DATA:
 546                 if (len == 18) {
 547                         traceState = TRACE_IDLE;
 548
 549                         if (isBlockTrailer(traceCurBlock)) {
 550                                 memcpy(traceCard + traceCurBlock * 16 + 6, data + 6, 4);
 551                         } else {
 552                                 memcpy(traceCard + traceCurBlock * 16, data, 16);
 553                         }
 554                         if (wantSaveToEmlFile) saveTraceCard();
 555                         return 0;
 556                 } else {
 557                         traceState = TRACE_ERROR;
 558                         return 1;
 559                 }
 560         break;
 561
 562         case TRACE_WRITE_OK:
 563                 if ((len == 1) && (data[0] == 0x0a)) {
 564                         traceState = TRACE_WRITE_DATA;
 565
 566                         return 0;
 567                 } else {
 568                         traceState = TRACE_ERROR;
 569                         return 1;
 570                 }
 571         break;
 572
 573         case TRACE_WRITE_DATA:
 574                 if (len == 18) {
 575                         traceState = TRACE_IDLE;
 576
 577                         memcpy(traceCard + traceCurBlock * 16, data, 16);
 578                         if (wantSaveToEmlFile) saveTraceCard();
 579                         return 0;
 580                 } else {
 581                         traceState = TRACE_ERROR;
 582                         return 1;
 583                 }
 584         break;
 585
 586         case TRACE_AUTH1:
 587                 if (len == 4) {
 588                         traceState = TRACE_AUTH2;
 589                         nt = bytes_to_num(data, 4);
 590                         return 0;
 591                 } else {
 592                         traceState = TRACE_ERROR;
 593                         return 1;
 594                 }
 595         break;
 596
 597         case TRACE_AUTH2:
 598                 if (len == 8) {
 599                         traceState = TRACE_AUTH_OK;
 600
 601                         nr_enc = bytes_to_num(data, 4);
 602                         ar_enc = bytes_to_num(data + 4, 4);
 603                         return 0;
 604                 } else {
 605                         traceState = TRACE_ERROR;
 606                         return 1;
 607                 }
 608         break;
 609
 610         case TRACE_AUTH_OK:
 611                 if (len ==4) {
 612                         traceState = TRACE_IDLE;
 613
 614                         at_enc = bytes_to_num(data, 4);
 615
 616                         //  decode key here)
 617                         ks2 = ar_enc ^ prng_successor(nt, 64);
 618                         ks3 = at_enc ^ prng_successor(nt, 96);
 619                         revstate = lfsr_recovery64(ks2, ks3);
 620                         lfsr_rollback_word(revstate, 0, 0);
 621                         lfsr_rollback_word(revstate, 0, 0);
 622                         lfsr_rollback_word(revstate, nr_enc, 1);
 623                         lfsr_rollback_word(revstate, uid ^ nt, 0);
 624
 625                         crypto1_get_lfsr(revstate, &key);
 626                         printf("Key: %012"llx"\n",key);
 627                         AddLogUint64(logHexFileName, "key: ", key);
 628
 629                         int blockShift = ((traceCurBlock & 0xFC) + 3) * 16;
 630                         if (isBlockEmpty((traceCurBlock & 0xFC) + 3)) memcpy(traceCard + blockShift + 6, trailerAccessBytes, 4);
 631
 632                         if (traceCurKey) {
 633                                 num_to_bytes(key, 6, traceCard + blockShift + 10);
 634                         } else {
 635                                 num_to_bytes(key, 6, traceCard + blockShift);
 636                         }
 637                         if (wantSaveToEmlFile) saveTraceCard();
 638
 639                         if (traceCrypto1) {
 640                                 crypto1_destroy(traceCrypto1);
 641                         }
 642
 643                         // set cryptosystem state
 644                         traceCrypto1 = lfsr_recovery64(ks2, ks3);
 645
 646 //      nt = crypto1_word(traceCrypto1, nt ^ uid, 1) ^ nt;
 647
 648         /*      traceCrypto1 = crypto1_create(key); // key in lfsr
 649                 crypto1_word(traceCrypto1, nt ^ uid, 0);
 650                 crypto1_word(traceCrypto1, ar, 1);
 651                 crypto1_word(traceCrypto1, 0, 0);
 652                 crypto1_word(traceCrypto1, 0, 0);*/
 653
 654                         return 0;
 655                 } else {
 656                         traceState = TRACE_ERROR;
 657                         return 1;
 658                 }
 659         break;
 660
 661         default:
 662                 traceState = TRACE_ERROR;
 663                 return 1;
 664         }
 665
 666         return 0;
 667 }
 668
 669 int tryDecryptWord(uint32_t nt, uint32_t ar_enc, uint32_t at_enc, uint8_t *data, int len){
 670         /*
 671         uint32_t nt;      // tag challenge
 672         uint32_t nr_enc;  // encrypted reader challenge
 673         uint32_t ar_enc;  // encrypted reader response
 674         uint32_t at_enc;  // encrypted tag response
 675         */
 676         struct Crypto1State *pcs = NULL;
 677
 678         ks2 = ar_enc ^ prng_successor(nt, 64);
 679         ks3 = at_enc ^ prng_successor(nt, 96);
 680
 681         PrintAndLog("Decrypting data with:");
 682         PrintAndLog("      nt: %08x",nt);
 683         PrintAndLog("  ar_enc: %08x",ar_enc);
 684         PrintAndLog("  at_enc: %08x",at_enc);
 685         PrintAndLog("\nEncrypted data: [%s]", sprint_hex(data,len) );
 686
 687         pcs = lfsr_recovery64(ks2, ks3);
 688         mf_crypto1_decrypt(pcs, data, len, FALSE);
 689         PrintAndLog("Decrypted data: [%s]", sprint_hex(data,len) );
 690         crypto1_destroy(pcs);
 691         return 0;
 692 }