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 #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         struct Crypto1State *p1;
  70         StateList_t *statelist = arg;
  71         statelist->head.slhead = lfsr_recovery32(statelist->ks1, statelist->nt ^ statelist->uid);
  72
  73         for (p1 = statelist->head.slhead; *(uint64_t *)p1 != 0; p1++);
  74
  75         statelist->len = p1 - statelist->head.slhead;
  76         statelist->tail.sltail = --p1;
  77         qsort(statelist->head.slhead, statelist->len, sizeof(uint64_t), Compare16Bits);
  78         return statelist->head.slhead;
  79 }
  80
  81 int mfnested(uint8_t blockNo, uint8_t keyType, uint8_t * key, uint8_t trgBlockNo, uint8_t trgKeyType, uint8_t * resultKey, bool calibrate)
  82 {
  83         uint16_t i;
  84         uint32_t uid;
  85         UsbCommand resp;
  86         StateList_t statelists[2];
  87         struct Crypto1State *p1, *p2, *p3, *p4;
  88
  89         UsbCommand c = {CMD_MIFARE_NESTED, {blockNo + keyType * 0x100, trgBlockNo + trgKeyType * 0x100, calibrate}};
  90         memcpy(c.d.asBytes, key, 6);
  91         clearCommandBuffer();
  92         SendCommand(&c);
  93         if (!WaitForResponseTimeout(CMD_ACK, &resp, 1500)) return -1;
  94
  95         // error during nested
  96         if (resp.arg[0]) return resp.arg[0];
  97
  98         memcpy(&uid, resp.d.asBytes, 4);
  99
 100         for (i = 0; i < 2; i++) {
 101                 statelists[i].blockNo = resp.arg[2] & 0xff;
 102                 statelists[i].keyType = (resp.arg[2] >> 8) & 0xff;
 103                 statelists[i].uid = uid;
 104                 memcpy(&statelists[i].nt,  (void *)(resp.d.asBytes + 4 + i * 8 + 0), 4);
 105                 memcpy(&statelists[i].ks1, (void *)(resp.d.asBytes + 4 + i * 8 + 4), 4);
 106         }
 107
 108         // calc keys
 109         pthread_t thread_id[2];
 110
 111         // create and run worker threads
 112         for (i = 0; i < 2; i++)
 113                 pthread_create(thread_id + i, NULL, nested_worker_thread, &statelists[i]);
 114
 115         // wait for threads to terminate:
 116         for (i = 0; i < 2; i++)
 117                 pthread_join(thread_id[i], (void*)&statelists[i].head.slhead);
 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
 125         while (p1 <= statelists[0].tail.sltail && p2 <= statelists[1].tail.sltail) {
 126                 if (Compare16Bits(p1, p2) == 0) {
 127
 128                         struct Crypto1State savestate, *savep = &savestate;
 129                         savestate = *p1;
 130                         while(Compare16Bits(p1, savep) == 0 && p1 <= statelists[0].tail.sltail) {
 131                                 *p3 = *p1;
 132                                 lfsr_rollback_word(p3, statelists[0].nt ^ statelists[0].uid, 0);
 133                                 p3++;
 134                                 p1++;
 135                         }
 136                         savestate = *p2;
 137                         while(Compare16Bits(p2, savep) == 0 && p2 <= statelists[1].tail.sltail) {
 138                                 *p4 = *p2;
 139                                 lfsr_rollback_word(p4, statelists[1].nt ^ statelists[1].uid, 0);
 140                                 p4++;
 141                                 p2++;
 142                         }
 143                 }
 144                 else {
 145                         while (Compare16Bits(p1, p2) == -1) p1++;
 146                         while (Compare16Bits(p1, p2) == 1) p2++;
 147                 }
 148         }
 149
 150         p3->even = 0; p3->odd = 0;
 151         p4->even = 0; p4->odd = 0;
 152         statelists[0].len = p3 - statelists[0].head.slhead;
 153         statelists[1].len = p4 - statelists[1].head.slhead;
 154         statelists[0].tail.sltail=--p3;
 155         statelists[1].tail.sltail=--p4;
 156
 157         // the statelists now contain possible keys. The key we are searching for must be in the
 158         // intersection of both lists. Create the intersection:
 159         qsort(statelists[0].head.keyhead, statelists[0].len, sizeof(uint64_t), compar_int);
 160         qsort(statelists[1].head.keyhead, statelists[1].len, sizeof(uint64_t), compar_int);
 161
 162         uint64_t *p5, *p6, *p7;
 163         p5 = p7 = statelists[0].head.keyhead;
 164         p6 = statelists[1].head.keyhead;
 165
 166         while (p5 <= statelists[0].tail.keytail && p6 <= statelists[1].tail.keytail) {
 167                 if (compar_int(p5, p6) == 0) {
 168                         *p7++ = *p5++;
 169                         p6++;
 170                 }
 171                 else {
 172                         while (compar_int(p5, p6) == -1) p5++;
 173                         while (compar_int(p5, p6) == 1) p6++;
 174                 }
 175         }
 176         statelists[0].len = p7 - statelists[0].head.keyhead;
 177         statelists[0].tail.keytail = --p7;
 178
 179         uint32_t numOfCandidates = statelists[0].len;
 180         if ( numOfCandidates == 0 ) goto out;
 181
 182         memset(resultKey, 0, 6);
 183         uint64_t key64 = 0;
 184
 185         // The list may still contain several key candidates. Test each of them with mfCheckKeys
 186         // uint32_t max_keys = keycnt > (USB_CMD_DATA_SIZE/6) ? (USB_CMD_DATA_SIZE/6) : keycnt;
 187         uint8_t keyBlock[USB_CMD_DATA_SIZE] = {0x00};
 188
 189         for (i = 0; i < numOfCandidates; ++i){
 190                 crypto1_get_lfsr(statelists[0].head.slhead + i, &key64);
 191                 num_to_bytes(key64, 6, keyBlock + i * 6);
 192         }
 193
 194         if (!mfCheckKeys(statelists[0].blockNo, statelists[0].keyType, false, numOfCandidates, keyBlock, &key64)) {
 195                 free(statelists[0].head.slhead);
 196                 free(statelists[1].head.slhead);
 197                 num_to_bytes(key64, 6, resultKey);
 198
 199                 PrintAndLog("UID: %08x target block:%3u key type: %c  -- Found key [%012"llx"]",
 200                         uid,
 201                         (uint16_t)resp.arg[2] & 0xff,
 202                         (resp.arg[2] >> 8) ? 'B' : 'A',
 203                         key64
 204                 );
 205                 return -5;
 206         }
 207
 208 out:
 209         PrintAndLog("UID: %08x target block:%3u key type: %c",
 210                         uid,
 211                         (uint16_t)resp.arg[2] & 0xff,
 212                         (resp.arg[2] >> 8) ? 'B' : 'A'
 213         );
 214
 215         free(statelists[0].head.slhead);
 216         free(statelists[1].head.slhead);
 217         return -4;
 218 }
 219
 220 int mfCheckKeys (uint8_t blockNo, uint8_t keyType, bool clear_trace, uint8_t keycnt, uint8_t * keyBlock, uint64_t * key){
 221         *key = 0;
 222         UsbCommand c = {CMD_MIFARE_CHKKEYS, { (blockNo | (keyType<<8)), clear_trace, keycnt}};
 223         memcpy(c.d.asBytes, keyBlock, 6 * keycnt);
 224         clearCommandBuffer();
 225         SendCommand(&c);
 226         UsbCommand resp;
 227         if (!WaitForResponseTimeout(CMD_ACK, &resp, 2500)) return 1;
 228         if ((resp.arg[0] & 0xff) != 0x01) return 2;
 229         *key = bytes_to_num(resp.d.asBytes, 6);
 230         return 0;
 231 }
 232
 233 // EMULATOR
 234
 235 int mfEmlGetMem(uint8_t *data, int blockNum, int blocksCount) {
 236         UsbCommand c = {CMD_MIFARE_EML_MEMGET, {blockNum, blocksCount, 0}};
 237         clearCommandBuffer();
 238         SendCommand(&c);
 239         UsbCommand resp;
 240         if (!WaitForResponseTimeout(CMD_ACK,&resp,1500)) return 1;
 241         memcpy(data, resp.d.asBytes, blocksCount * 16);
 242         return 0;
 243 }
 244
 245 int mfEmlSetMem(uint8_t *data, int blockNum, int blocksCount) {
 246         return mfEmlSetMem_xt(data, blockNum, blocksCount, 16);
 247 }
 248
 249 int mfEmlSetMem_xt(uint8_t *data, int blockNum, int blocksCount, int blockBtWidth) {
 250         UsbCommand c = {CMD_MIFARE_EML_MEMSET, {blockNum, blocksCount, blockBtWidth}};
 251         memcpy(c.d.asBytes, data, blocksCount * blockBtWidth);
 252         clearCommandBuffer();
 253         SendCommand(&c);
 254         return 0;
 255 }
 256
 257 // "MAGIC" CARD
 258 int mfCSetUID(uint8_t *uid, uint8_t *atqa, uint8_t *sak, uint8_t *oldUID, uint8_t wipecard) {
 259
 260         uint8_t params = MAGIC_SINGLE;
 261         uint8_t block0[16];
 262         memset(block0, 0x00, sizeof(block0));
 263
 264         int old = mfCGetBlock(0, block0, params);
 265         if (old == 0)
 266                 PrintAndLog("old block 0:  %s", sprint_hex(block0, sizeof(block0)));
 267         else
 268                 PrintAndLog("Couldn't get old data. Will write over the last bytes of Block 0.");
 269
 270         // fill in the new values
 271         // UID
 272         memcpy(block0, uid, 4);
 273         // Mifare UID BCC
 274         block0[4] = block0[0]^block0[1]^block0[2]^block0[3];
 275         // mifare classic SAK(byte 5) and ATQA(byte 6 and 7, reversed)
 276         if ( sak != NULL )
 277                 block0[5]=sak[0];
 278
 279         if ( atqa != NULL ) {
 280                 block0[6]=atqa[1];
 281                 block0[7]=atqa[0];
 282         }
 283         PrintAndLog("new block 0:  %s", sprint_hex(block0,16));
 284
 285         if ( wipecard )          params |= MAGIC_WIPE;
 286         if ( oldUID == NULL) params |= MAGIC_UID;
 287
 288         return mfCSetBlock(0, block0, oldUID, params);
 289 }
 290
 291 int mfCSetBlock(uint8_t blockNo, uint8_t *data, uint8_t *uid, uint8_t params) {
 292
 293         uint8_t isOK = 0;
 294         UsbCommand c = {CMD_MIFARE_CSETBLOCK, {params, blockNo, 0}};
 295         memcpy(c.d.asBytes, data, 16);
 296         clearCommandBuffer();
 297         SendCommand(&c);
 298         UsbCommand resp;
 299         if (WaitForResponseTimeout(CMD_ACK, &resp, 1500)) {
 300                 isOK  = resp.arg[0] & 0xff;
 301                 if (uid != NULL)
 302                         memcpy(uid, resp.d.asBytes, 4);
 303                 if (!isOK)
 304                         return 2;
 305         } else {
 306                 PrintAndLog("Command execute timeout");
 307                 return 1;
 308         }
 309         return 0;
 310 }
 311
 312 int mfCGetBlock(uint8_t blockNo, uint8_t *data, uint8_t params) {
 313         uint8_t isOK = 0;
 314         UsbCommand c = {CMD_MIFARE_CGETBLOCK, {params, blockNo, 0}};
 315         clearCommandBuffer();
 316         SendCommand(&c);
 317         UsbCommand resp;
 318         if (WaitForResponseTimeout(CMD_ACK,&resp,1500)) {
 319                 isOK  = resp.arg[0] & 0xff;
 320                 memcpy(data, resp.d.asBytes, 16);
 321                 if (!isOK) return 2;
 322         } else {
 323                 PrintAndLog("Command execute timeout");
 324                 return 1;
 325         }
 326         return 0;
 327 }
 328
 329 // SNIFFER
 330 // [iceman] so many global variables....
 331
 332 // constants
 333 static uint8_t trailerAccessBytes[4] = {0x08, 0x77, 0x8F, 0x00};
 334
 335 // variables
 336 char logHexFileName[FILE_PATH_SIZE] = {0x00};
 337 static uint8_t traceCard[4096] = {0x00};
 338 static char traceFileName[FILE_PATH_SIZE] = {0x00};
 339 static int traceState = TRACE_IDLE;
 340 static uint8_t traceCurBlock = 0;
 341 static uint8_t traceCurKey = 0;
 342
 343 struct Crypto1State *traceCrypto1 = NULL;
 344 struct Crypto1State *revstate = NULL;
 345
 346 uint64_t key = 0;
 347 uint32_t ks2 = 0;
 348 uint32_t ks3 = 0;
 349
 350 uint32_t uid = 0;     // serial number
 351 uint32_t nt =0;      // tag challenge
 352 uint32_t nr_enc =0;  // encrypted reader challenge
 353 uint32_t ar_enc =0;  // encrypted reader response
 354 uint32_t at_enc =0;  // encrypted tag response
 355
 356 int isTraceCardEmpty(void) {
 357         return ((traceCard[0] == 0) && (traceCard[1] == 0) && (traceCard[2] == 0) && (traceCard[3] == 0));
 358 }
 359
 360 int isBlockEmpty(int blockN) {
 361         for (int i = 0; i < 16; i++)
 362                 if (traceCard[blockN * 16 + i] != 0) return 0;
 363
 364         return 1;
 365 }
 366
 367 int isBlockTrailer(int blockN) {
 368         return ((blockN & 0x03) == 0x03);
 369 }
 370
 371 int loadTraceCard(uint8_t *tuid) {
 372         FILE * f;
 373         char buf[64] = {0x00};
 374         uint8_t buf8[64] = {0x00};
 375         int i, blockNum;
 376
 377         if (!isTraceCardEmpty())
 378                 saveTraceCard();
 379
 380         memset(traceCard, 0x00, 4096);
 381         memcpy(traceCard, tuid + 3, 4);
 382
 383         FillFileNameByUID(traceFileName, tuid, ".eml", 7);
 384
 385         f = fopen(traceFileName, "r");
 386         if (!f) return 1;
 387
 388         blockNum = 0;
 389
 390         while(!feof(f)){
 391
 392                 memset(buf, 0, sizeof(buf));
 393                 if (fgets(buf, sizeof(buf), f) == NULL) {
 394                         PrintAndLog("File reading error.");
 395                         fclose(f);
 396                         return 2;
 397                 }
 398
 399                 if (strlen(buf) < 32){
 400                         if (feof(f)) break;
 401                         PrintAndLog("File content error. Block data must include 32 HEX symbols");
 402                         fclose(f);
 403                         return 2;
 404                 }
 405                 for (i = 0; i < 32; i += 2)
 406                         sscanf(&buf[i], "%02x", (unsigned int *)&buf8[i / 2]);
 407
 408                 memcpy(traceCard + blockNum * 16, buf8, 16);
 409
 410                 blockNum++;
 411         }
 412         fclose(f);
 413
 414         return 0;
 415 }
 416
 417 int saveTraceCard(void) {
 418         FILE * f;
 419
 420         if ((!strlen(traceFileName)) || (isTraceCardEmpty())) return 0;
 421
 422         f = fopen(traceFileName, "w+");
 423         if ( !f ) return 1;
 424
 425         for (int i = 0; i < 64; i++) {  // blocks
 426                 for (int j = 0; j < 16; j++)  // bytes
 427                         fprintf(f, "%02x", *(traceCard + i * 16 + j));
 428                 fprintf(f,"\n");
 429         }
 430         fclose(f);
 431         return 0;
 432 }
 433
 434 int mfTraceInit(uint8_t *tuid, uint8_t *atqa, uint8_t sak, bool wantSaveToEmlFile) {
 435
 436         if (traceCrypto1)
 437                 crypto1_destroy(traceCrypto1);
 438
 439         traceCrypto1 = NULL;
 440
 441         if (wantSaveToEmlFile)
 442                 loadTraceCard(tuid);
 443
 444         traceCard[4] = traceCard[0] ^ traceCard[1] ^ traceCard[2] ^ traceCard[3];
 445         traceCard[5] = sak;
 446         memcpy(&traceCard[6], atqa, 2);
 447         traceCurBlock = 0;
 448         uid = bytes_to_num(tuid + 3, 4);
 449
 450         traceState = TRACE_IDLE;
 451
 452         return 0;
 453 }
 454
 455 void mf_crypto1_decrypt(struct Crypto1State *pcs, uint8_t *data, int len, bool isEncrypted){
 456         uint8_t bt = 0;
 457         int i;
 458
 459         if (len != 1) {
 460                 for (i = 0; i < len; i++)
 461                         data[i] = crypto1_byte(pcs, 0x00, isEncrypted) ^ data[i];
 462         } else {
 463                 bt = 0;
 464                 bt |= (crypto1_bit(pcs, 0, isEncrypted) ^ BIT(data[0], 0)) << 0;
 465                 bt |= (crypto1_bit(pcs, 0, isEncrypted) ^ BIT(data[0], 1)) << 1;
 466                 bt |= (crypto1_bit(pcs, 0, isEncrypted) ^ BIT(data[0], 2)) << 2;
 467                 bt |= (crypto1_bit(pcs, 0, isEncrypted) ^ BIT(data[0], 3)) << 3;
 468                 data[0] = bt;
 469         }
 470         return;
 471 }
 472
 473 int mfTraceDecode(uint8_t *data_src, int len, bool wantSaveToEmlFile) {
 474
 475         uint8_t data[64];
 476         memset(data, 0x00, sizeof(data));
 477
 478         if (traceState == TRACE_ERROR) return 1;
 479
 480         if (len > 64) {
 481                 traceState = TRACE_ERROR;
 482                 return 1;
 483         }
 484
 485         memcpy(data, data_src, len);
 486         if ((traceCrypto1) && ((traceState == TRACE_IDLE) || (traceState > TRACE_AUTH_OK))) {
 487                 mf_crypto1_decrypt(traceCrypto1, data, len, 0);
 488                 PrintAndLog("dec> %s", sprint_hex(data, len));
 489                 AddLogHex(logHexFileName, "dec> ", data, len);
 490         }
 491
 492         switch (traceState) {
 493         case TRACE_IDLE:
 494                 // check packet crc16!
 495                 if ((len >= 4) && (!CheckCrc14443(CRC_14443_A, data, len))) {
 496                         PrintAndLog("dec> CRC ERROR!!!");
 497                         AddLogLine(logHexFileName, "dec> ", "CRC ERROR!!!");
 498                         traceState = TRACE_ERROR;  // do not decrypt the next commands
 499                         return 1;
 500                 }
 501
 502                 // AUTHENTICATION
 503                 if ((len == 4) && ((data[0] == MIFARE_AUTH_KEYA) || (data[0] == MIFARE_AUTH_KEYB))) {
 504                         traceState = TRACE_AUTH1;
 505                         traceCurBlock = data[1];
 506                         traceCurKey = data[0] == 60 ? 1:0;
 507                         return 0;
 508                 }
 509
 510                 // READ
 511                 if ((len ==4) && ((data[0] == ISO14443A_CMD_READBLOCK))) {
 512                         traceState = TRACE_READ_DATA;
 513                         traceCurBlock = data[1];
 514                         return 0;
 515                 }
 516
 517                 // WRITE
 518                 if ((len ==4) && ((data[0] == ISO14443A_CMD_WRITEBLOCK))) {
 519                         traceState = TRACE_WRITE_OK;
 520                         traceCurBlock = data[1];
 521                         return 0;
 522                 }
 523
 524                 // HALT
 525                 if ((len ==4) && ((data[0] == ISO14443A_CMD_HALT) && (data[1] == 0x00))) {
 526                         traceState = TRACE_ERROR;  // do not decrypt the next commands
 527                         return 0;
 528                 }
 529
 530                 return 0;
 531         break;
 532
 533         case TRACE_READ_DATA:
 534                 if (len == 18) {
 535                         traceState = TRACE_IDLE;
 536
 537                         if (isBlockTrailer(traceCurBlock)) {
 538                                 memcpy(traceCard + traceCurBlock * 16 + 6, data + 6, 4);
 539                         } else {
 540                                 memcpy(traceCard + traceCurBlock * 16, data, 16);
 541                         }
 542                         if (wantSaveToEmlFile) saveTraceCard();
 543                         return 0;
 544                 } else {
 545                         traceState = TRACE_ERROR;
 546                         return 1;
 547                 }
 548         break;
 549
 550         case TRACE_WRITE_OK:
 551                 if ((len == 1) && (data[0] == 0x0a)) {
 552                         traceState = TRACE_WRITE_DATA;
 553
 554                         return 0;
 555                 } else {
 556                         traceState = TRACE_ERROR;
 557                         return 1;
 558                 }
 559         break;
 560
 561         case TRACE_WRITE_DATA:
 562                 if (len == 18) {
 563                         traceState = TRACE_IDLE;
 564
 565                         memcpy(traceCard + traceCurBlock * 16, data, 16);
 566                         if (wantSaveToEmlFile) saveTraceCard();
 567                         return 0;
 568                 } else {
 569                         traceState = TRACE_ERROR;
 570                         return 1;
 571                 }
 572         break;
 573
 574         case TRACE_AUTH1:
 575                 if (len == 4) {
 576                         traceState = TRACE_AUTH2;
 577                         nt = bytes_to_num(data, 4);
 578                         return 0;
 579                 } else {
 580                         traceState = TRACE_ERROR;
 581                         return 1;
 582                 }
 583         break;
 584
 585         case TRACE_AUTH2:
 586                 if (len == 8) {
 587                         traceState = TRACE_AUTH_OK;
 588
 589                         nr_enc = bytes_to_num(data, 4);
 590                         ar_enc = bytes_to_num(data + 4, 4);
 591                         return 0;
 592                 } else {
 593                         traceState = TRACE_ERROR;
 594                         return 1;
 595                 }
 596         break;
 597
 598         case TRACE_AUTH_OK:
 599                 if (len ==4) {
 600                         traceState = TRACE_IDLE;
 601
 602                         at_enc = bytes_to_num(data, 4);
 603
 604                         //  decode key here)
 605                         ks2 = ar_enc ^ prng_successor(nt, 64);
 606                         ks3 = at_enc ^ prng_successor(nt, 96);
 607                         revstate = lfsr_recovery64(ks2, ks3);
 608                         lfsr_rollback_word(revstate, 0, 0);
 609                         lfsr_rollback_word(revstate, 0, 0);
 610                         lfsr_rollback_word(revstate, nr_enc, 1);
 611                         lfsr_rollback_word(revstate, uid ^ nt, 0);
 612
 613                         crypto1_get_lfsr(revstate, &key);
 614                         printf("Key: %012"llx"\n",key);
 615                         AddLogUint64(logHexFileName, "key: ", key);
 616
 617                         int blockShift = ((traceCurBlock & 0xFC) + 3) * 16;
 618                         if (isBlockEmpty((traceCurBlock & 0xFC) + 3)) memcpy(traceCard + blockShift + 6, trailerAccessBytes, 4);
 619
 620                         if (traceCurKey) {
 621                                 num_to_bytes(key, 6, traceCard + blockShift + 10);
 622                         } else {
 623                                 num_to_bytes(key, 6, traceCard + blockShift);
 624                         }
 625                         if (wantSaveToEmlFile) saveTraceCard();
 626
 627                         if (traceCrypto1) {
 628                                 crypto1_destroy(traceCrypto1);
 629                         }
 630
 631                         // set cryptosystem state
 632                         traceCrypto1 = lfsr_recovery64(ks2, ks3);
 633
 634 //      nt = crypto1_word(traceCrypto1, nt ^ uid, 1) ^ nt;
 635
 636         /*      traceCrypto1 = crypto1_create(key); // key in lfsr
 637                 crypto1_word(traceCrypto1, nt ^ uid, 0);
 638                 crypto1_word(traceCrypto1, ar, 1);
 639                 crypto1_word(traceCrypto1, 0, 0);
 640                 crypto1_word(traceCrypto1, 0, 0);*/
 641
 642                         return 0;
 643                 } else {
 644                         traceState = TRACE_ERROR;
 645                         return 1;
 646                 }
 647         break;
 648
 649         default:
 650                 traceState = TRACE_ERROR;
 651                 return 1;
 652         }
 653
 654         return 0;
 655 }
 656
 657 int tryDecryptWord(uint32_t nt, uint32_t ar_enc, uint32_t at_enc, uint8_t *data, int len){
 658         /*
 659         uint32_t nt;      // tag challenge
 660         uint32_t nr_enc;  // encrypted reader challenge
 661         uint32_t ar_enc;  // encrypted reader response
 662         uint32_t at_enc;  // encrypted tag response
 663         */
 664         struct Crypto1State *pcs = NULL;
 665
 666         ks2 = ar_enc ^ prng_successor(nt, 64);
 667         ks3 = at_enc ^ prng_successor(nt, 96);
 668
 669         PrintAndLog("Decrypting data with:");
 670         PrintAndLog("      nt: %08x",nt);
 671         PrintAndLog("  ar_enc: %08x",ar_enc);
 672         PrintAndLog("  at_enc: %08x",at_enc);
 673         PrintAndLog("\nEncrypted data: [%s]", sprint_hex(data,len) );
 674
 675         pcs = lfsr_recovery64(ks2, ks3);
 676         mf_crypto1_decrypt(pcs, data, len, FALSE);
 677         PrintAndLog("Decrypted data: [%s]", sprint_hex(data,len) );
 678         crypto1_destroy(pcs);
 679         return 0;
 680 }