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         //return (*(int64_t*)b > *(int64_t*)a) - (*(int64_t*)b < *(int64_t*)a);
  31 }
  32
  33 // Compare 16 Bits out of cryptostate
  34 int Compare16Bits(const void * a, const void * b) {
  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         // return
  46                 // ((*(int64_t*)b & 0x00ff000000ff0000) > (*(int64_t*)a & 0x00ff000000ff0000))
  47                 // -
  48                 // ((*(int64_t*)b & 0x00ff000000ff0000) < (*(int64_t*)a & 0x00ff000000ff0000))
  49                 // ;
  50 }
  51
  52 typedef
  53         struct {
  54                 union {
  55                         struct Crypto1State *slhead;
  56                         uint64_t *keyhead;
  57                 } head;
  58                 union {
  59                         struct Crypto1State *sltail;
  60                         uint64_t *keytail;
  61                 } tail;
  62                 uint32_t len;
  63                 uint32_t uid;
  64                 uint32_t blockNo;
  65                 uint32_t keyType;
  66                 uint32_t nt;
  67                 uint32_t ks1;
  68         } StateList_t;
  69
  70
  71 // wrapper function for multi-threaded lfsr_recovery32
  72 void* nested_worker_thread(void *arg)
  73 {
  74         struct Crypto1State *p1;
  75         StateList_t *statelist = arg;
  76
  77         statelist->head.slhead = lfsr_recovery32(statelist->ks1, statelist->nt ^ statelist->uid);
  78
  79         for (p1 = statelist->head.slhead; *(uint64_t *)p1 != 0; ++p1);
  80
  81         statelist->len = p1 - statelist->head.slhead;
  82         statelist->tail.sltail = --p1;
  83         qsort(statelist->head.slhead, statelist->len, sizeof(uint64_t), Compare16Bits);
  84
  85         return statelist->head.slhead;
  86 }
  87
  88 int mfnested(uint8_t blockNo, uint8_t keyType, uint8_t * key, uint8_t trgBlockNo, uint8_t trgKeyType, uint8_t * resultKey, bool calibrate)
  89 {
  90         uint16_t i;
  91         uint32_t uid;
  92         UsbCommand resp;
  93         StateList_t statelists[2];
  94         struct Crypto1State *p1, *p2, *p3, *p4;
  95
  96         UsbCommand c = {CMD_MIFARE_NESTED, {blockNo + keyType * 0x100, trgBlockNo + trgKeyType * 0x100, calibrate}};
  97         memcpy(c.d.asBytes, key, 6);
  98         clearCommandBuffer();
  99         SendCommand(&c);
 100         if (!WaitForResponseTimeout(CMD_ACK, &resp, 1500)) return -1;
 101
 102         // error during nested
 103         if (resp.arg[0]) return resp.arg[0];
 104
 105         memcpy(&uid, resp.d.asBytes, 4);
 106
 107         for (i = 0; i < 2; ++i) {
 108                 statelists[i].blockNo = resp.arg[2] & 0xff;
 109                 statelists[i].keyType = (resp.arg[2] >> 8) & 0xff;
 110                 statelists[i].uid = uid;
 111                 memcpy(&statelists[i].nt,  (void *)(resp.d.asBytes + 4 + i * 8 + 0), 4);
 112                 memcpy(&statelists[i].ks1, (void *)(resp.d.asBytes + 4 + i * 8 + 4), 4);
 113         }
 114
 115         // calc keys
 116         pthread_t thread_id[2];
 117
 118         // create and run worker threads
 119         for (i = 0; i < 2; i++)
 120                 pthread_create(thread_id + i, NULL, nested_worker_thread, &statelists[i]);
 121
 122         // wait for threads to terminate:
 123         for (i = 0; i < 2; i++)
 124                 pthread_join(thread_id[i], (void*)&statelists[i].head.slhead);
 125
 126
 127         // the first 16 Bits of the cryptostate already contain part of our key.
 128         // Create the intersection of the two lists based on these 16 Bits and
 129         // roll back the cryptostate
 130         p1 = p3 = statelists[0].head.slhead;
 131         p2 = p4 = statelists[1].head.slhead;
 132         while (p1 <= statelists[0].tail.sltail && p2 <= statelists[1].tail.sltail) {
 133                 if (Compare16Bits(p1, p2) == 0) {
 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         //      clock_t t1 = clock();
 169         //radixSort(statelists[0].head.keyhead, statelists[0].len);
 170         //radixSort(statelists[1].head.keyhead, statelists[1].len);
 171         // t1 = clock() - t1;
 172         // PrintAndLog("radixsort, ticks %.0f", (float)t1);
 173
 174         uint64_t *p5, *p6, *p7;
 175         p5 = p7 = statelists[0].head.keyhead;
 176         p6 = statelists[1].head.keyhead;
 177         while (p5 <= statelists[0].tail.keytail && p6 <= statelists[1].tail.keytail) {
 178                 if (compar_int(p5, p6) == 0) {
 179                         *p7++ = *p5++;
 180                         p6++;
 181                 }
 182                 else {
 183                         while (compar_int(p5, p6) == -1) p5++;
 184                         while (compar_int(p5, p6) == 1) p6++;
 185                 }
 186         }
 187         statelists[0].len = p7 - statelists[0].head.keyhead;
 188         statelists[0].tail.keytail = --p7;
 189
 190         memset(resultKey, 0, 6);
 191         uint64_t key64 = 0;
 192
 193         // The list may still contain several key candidates. Test each of them with mfCheckKeys
 194         for (i = 0; i < statelists[0].len; i++) {
 195
 196                 crypto1_get_lfsr(statelists[0].head.slhead + i, &key64);
 197                 num_to_bytes(key64, 6, resultKey);
 198
 199                 if (!mfCheckKeys(statelists[0].blockNo, statelists[0].keyType, false, 1, resultKey, &key64)) {
 200                         free(statelists[0].head.slhead);
 201                         free(statelists[1].head.slhead);
 202                         PrintAndLog("UID: %08x target block:%3u key type: %c  -- Found key [%012"llx"]", uid, (uint16_t)resp.arg[2] & 0xff, (resp.arg[2] >> 8)?'B':'A', key64);
 203                         return -5;
 204                 }
 205         }
 206         PrintAndLog("UID: %08x target block:%3u key type: %c", uid, (uint16_t)resp.arg[2] & 0xff, (resp.arg[2] >> 8)?'B':'A');
 207         free(statelists[0].head.slhead);
 208         free(statelists[1].head.slhead);
 209         return -4;
 210 }
 211
 212 int mfCheckKeys (uint8_t blockNo, uint8_t keyType, bool clear_trace, uint8_t keycnt, uint8_t * keyBlock, uint64_t * key){
 213
 214         *key = 0;
 215         UsbCommand c = {CMD_MIFARE_CHKKEYS, { (blockNo | (keyType<<8)), clear_trace, keycnt}};
 216         memcpy(c.d.asBytes, keyBlock, 6 * keycnt);
 217         clearCommandBuffer();
 218         SendCommand(&c);
 219         UsbCommand resp;
 220         if (!WaitForResponseTimeout(CMD_ACK,&resp, 3000)) return 1;
 221         if ((resp.arg[0] & 0xff) != 0x01) return 2;
 222         *key = bytes_to_num(resp.d.asBytes, 6);
 223         return 0;
 224 }
 225
 226 // EMULATOR
 227
 228 int mfEmlGetMem(uint8_t *data, int blockNum, int blocksCount) {
 229         UsbCommand c = {CMD_MIFARE_EML_MEMGET, {blockNum, blocksCount, 0}};
 230         clearCommandBuffer();
 231         SendCommand(&c);
 232         UsbCommand resp;
 233         if (!WaitForResponseTimeout(CMD_ACK,&resp,1500)) return 1;
 234         memcpy(data, resp.d.asBytes, blocksCount * 16);
 235         return 0;
 236 }
 237
 238 int mfEmlSetMem(uint8_t *data, int blockNum, int blocksCount) {
 239         return mfEmlSetMem_xt(data, blockNum, blocksCount, 16);
 240 }
 241
 242 int mfEmlSetMem_xt(uint8_t *data, int blockNum, int blocksCount, int blockBtWidth) {
 243         UsbCommand c = {CMD_MIFARE_EML_MEMSET, {blockNum, blocksCount, blockBtWidth}};
 244         memcpy(c.d.asBytes, data, blocksCount * blockBtWidth);
 245
 246         clearCommandBuffer();
 247         SendCommand(&c);
 248         return 0;
 249 }
 250
 251 // "MAGIC" CARD
 252
 253 int mfCSetUID(uint8_t *uid, uint8_t *atqa, uint8_t *sak, uint8_t *oldUID, uint8_t wipecard) {
 254
 255         uint8_t params = MAGIC_SINGLE;
 256         uint8_t block0[16];
 257         memset(block0, 0x00, sizeof(block0));
 258
 259         int old = mfCGetBlock(0, block0, params);
 260         if (old == 0)
 261                 PrintAndLog("old block 0:  %s", sprint_hex(block0, sizeof(block0)));
 262         else
 263                 PrintAndLog("Couldn't get old data. Will write over the last bytes of Block 0.");
 264
 265         // fill in the new values
 266         // UID
 267         memcpy(block0, uid, 4);
 268         // Mifare UID BCC
 269         block0[4] = block0[0]^block0[1]^block0[2]^block0[3];
 270         // mifare classic SAK(byte 5) and ATQA(byte 6 and 7, reversed)
 271         if ( sak != NULL )
 272                 block0[5]=sak[0];
 273
 274         if ( atqa != NULL ) {
 275                 block0[6]=atqa[1];
 276                 block0[7]=atqa[0];
 277         }
 278         PrintAndLog("new block 0:  %s", sprint_hex(block0,16));
 279
 280         if ( wipecard )          params |= MAGIC_WIPE;
 281         if ( oldUID == NULL) params |= MAGIC_UID;
 282
 283         return mfCSetBlock(0, block0, oldUID, params);
 284 }
 285
 286 int mfCSetBlock(uint8_t blockNo, uint8_t *data, uint8_t *uid, uint8_t params) {
 287
 288         uint8_t isOK = 0;
 289         UsbCommand c = {CMD_MIFARE_CSETBLOCK, {params, blockNo, 0}};
 290         memcpy(c.d.asBytes, data, 16);
 291         clearCommandBuffer();
 292         SendCommand(&c);
 293         UsbCommand resp;
 294         if (WaitForResponseTimeout(CMD_ACK, &resp, 1500)) {
 295                 isOK  = resp.arg[0] & 0xff;
 296                 if (uid != NULL)
 297                         memcpy(uid, resp.d.asBytes, 4);
 298                 if (!isOK)
 299                         return 2;
 300         } else {
 301                 PrintAndLog("Command execute timeout");
 302                 return 1;
 303         }
 304         return 0;
 305 }
 306
 307 int mfCGetBlock(uint8_t blockNo, uint8_t *data, uint8_t params) {
 308         uint8_t isOK = 0;
 309         UsbCommand c = {CMD_MIFARE_CGETBLOCK, {params, blockNo, 0}};
 310         clearCommandBuffer();
 311         SendCommand(&c);
 312         UsbCommand resp;
 313         if (WaitForResponseTimeout(CMD_ACK,&resp,1500)) {
 314                 isOK  = resp.arg[0] & 0xff;
 315                 memcpy(data, resp.d.asBytes, 16);
 316                 if (!isOK) return 2;
 317         } else {
 318                 PrintAndLog("Command execute timeout");
 319                 return 1;
 320         }
 321         return 0;
 322 }
 323
 324 // SNIFFER
 325
 326 // constants
 327 static uint8_t trailerAccessBytes[4] = {0x08, 0x77, 0x8F, 0x00};
 328
 329 // variables
 330 char logHexFileName[FILE_PATH_SIZE] = {0x00};
 331 static uint8_t traceCard[4096] = {0x00};
 332 static char traceFileName[FILE_PATH_SIZE] = {0x00};
 333 static int traceState = TRACE_IDLE;
 334 static uint8_t traceCurBlock = 0;
 335 static uint8_t traceCurKey = 0;
 336
 337 struct Crypto1State *traceCrypto1 = NULL;
 338
 339 struct Crypto1State *revstate = NULL;
 340
 341 uint64_t key = 0;
 342 uint32_t ks2 = 0;
 343 uint32_t ks3 = 0;
 344
 345 uint32_t uid = 0;     // serial number
 346 uint32_t nt =0;      // tag challenge
 347 uint32_t nr_enc =0;  // encrypted reader challenge
 348 uint32_t ar_enc =0;  // encrypted reader response
 349 uint32_t at_enc =0;  // encrypted tag response
 350
 351 int isTraceCardEmpty(void) {
 352         return ((traceCard[0] == 0) && (traceCard[1] == 0) && (traceCard[2] == 0) && (traceCard[3] == 0));
 353 }
 354
 355 int isBlockEmpty(int blockN) {
 356         for (int i = 0; i < 16; i++)
 357                 if (traceCard[blockN * 16 + i] != 0) return 0;
 358
 359         return 1;
 360 }
 361
 362 int isBlockTrailer(int blockN) {
 363         return ((blockN & 0x03) == 0x03);
 364 }
 365
 366 int loadTraceCard(uint8_t *tuid) {
 367         FILE * f;
 368         char buf[64] = {0x00};
 369         uint8_t buf8[64] = {0x00};
 370         int i, blockNum;
 371
 372         if (!isTraceCardEmpty())
 373                 saveTraceCard();
 374
 375         memset(traceCard, 0x00, 4096);
 376         memcpy(traceCard, tuid + 3, 4);
 377
 378         FillFileNameByUID(traceFileName, tuid, ".eml", 7);
 379
 380         f = fopen(traceFileName, "r");
 381         if (!f) return 1;
 382
 383         blockNum = 0;
 384
 385         while(!feof(f)){
 386
 387                 memset(buf, 0, sizeof(buf));
 388                 if (fgets(buf, sizeof(buf), f) == NULL) {
 389                         PrintAndLog("File reading error.");
 390                         fclose(f);
 391                         return 2;
 392                 }
 393
 394                 if (strlen(buf) < 32){
 395                         if (feof(f)) break;
 396                         PrintAndLog("File content error. Block data must include 32 HEX symbols");
 397                         fclose(f);
 398                         return 2;
 399                 }
 400                 for (i = 0; i < 32; i += 2)
 401                         sscanf(&buf[i], "%02x", (unsigned int *)&buf8[i / 2]);
 402
 403                 memcpy(traceCard + blockNum * 16, buf8, 16);
 404
 405                 blockNum++;
 406         }
 407         fclose(f);
 408
 409         return 0;
 410 }
 411
 412 int saveTraceCard(void) {
 413         FILE * f;
 414
 415         if ((!strlen(traceFileName)) || (isTraceCardEmpty())) return 0;
 416
 417         f = fopen(traceFileName, "w+");
 418         if ( !f ) return 1;
 419
 420         for (int i = 0; i < 64; i++) {  // blocks
 421                 for (int j = 0; j < 16; j++)  // bytes
 422                         fprintf(f, "%02x", *(traceCard + i * 16 + j));
 423                 fprintf(f,"\n");
 424         }
 425         fclose(f);
 426         return 0;
 427 }
 428
 429 int mfTraceInit(uint8_t *tuid, uint8_t *atqa, uint8_t sak, bool wantSaveToEmlFile) {
 430
 431         if (traceCrypto1)
 432                 crypto1_destroy(traceCrypto1);
 433
 434         traceCrypto1 = NULL;
 435
 436         if (wantSaveToEmlFile)
 437                 loadTraceCard(tuid);
 438
 439         traceCard[4] = traceCard[0] ^ traceCard[1] ^ traceCard[2] ^ traceCard[3];
 440         traceCard[5] = sak;
 441         memcpy(&traceCard[6], atqa, 2);
 442         traceCurBlock = 0;
 443         uid = bytes_to_num(tuid + 3, 4);
 444
 445         traceState = TRACE_IDLE;
 446
 447         return 0;
 448 }
 449
 450 void mf_crypto1_decrypt(struct Crypto1State *pcs, uint8_t *data, int len, bool isEncrypted){
 451         uint8_t bt = 0;
 452         int i;
 453
 454         if (len != 1) {
 455                 for (i = 0; i < len; i++)
 456                         data[i] = crypto1_byte(pcs, 0x00, isEncrypted) ^ data[i];
 457         } else {
 458                 bt = 0;
 459                 bt |= (crypto1_bit(pcs, 0, isEncrypted) ^ BIT(data[0], 0)) << 0;
 460                 bt |= (crypto1_bit(pcs, 0, isEncrypted) ^ BIT(data[0], 1)) << 1;
 461                 bt |= (crypto1_bit(pcs, 0, isEncrypted) ^ BIT(data[0], 2)) << 2;
 462                 bt |= (crypto1_bit(pcs, 0, isEncrypted) ^ BIT(data[0], 3)) << 3;
 463                 data[0] = bt;
 464         }
 465         return;
 466 }
 467
 468 int mfTraceDecode(uint8_t *data_src, int len, bool wantSaveToEmlFile) {
 469
 470         uint8_t data[64];
 471
 472         if (traceState == TRACE_ERROR) return 1;
 473
 474         if (len > 64) {
 475                 traceState = TRACE_ERROR;
 476                 return 1;
 477         }
 478
 479         memcpy(data, data_src, len);
 480         if ((traceCrypto1) && ((traceState == TRACE_IDLE) || (traceState > TRACE_AUTH_OK))) {
 481                 mf_crypto1_decrypt(traceCrypto1, data, len, 0);
 482                 PrintAndLog("dec> %s", sprint_hex(data, len));
 483                 AddLogHex(logHexFileName, "dec> ", data, len);
 484         }
 485
 486         switch (traceState) {
 487         case TRACE_IDLE:
 488                 // check packet crc16!
 489                 if ((len >= 4) && (!CheckCrc14443(CRC_14443_A, data, len))) {
 490                         PrintAndLog("dec> CRC ERROR!!!");
 491                         AddLogLine(logHexFileName, "dec> ", "CRC ERROR!!!");
 492                         traceState = TRACE_ERROR;  // do not decrypt the next commands
 493                         return 1;
 494                 }
 495
 496                 // AUTHENTICATION
 497                 if ((len == 4) && ((data[0] == 0x60) || (data[0] == 0x61))) {
 498                         traceState = TRACE_AUTH1;
 499                         traceCurBlock = data[1];
 500                         traceCurKey = data[0] == 60 ? 1:0;
 501                         return 0;
 502                 }
 503
 504                 // READ
 505                 if ((len ==4) && ((data[0] == 0x30))) {
 506                         traceState = TRACE_READ_DATA;
 507                         traceCurBlock = data[1];
 508                         return 0;
 509                 }
 510
 511                 // WRITE
 512                 if ((len ==4) && ((data[0] == 0xA0))) {
 513                         traceState = TRACE_WRITE_OK;
 514                         traceCurBlock = data[1];
 515                         return 0;
 516                 }
 517
 518                 // HALT
 519                 if ((len ==4) && ((data[0] == 0x50) && (data[1] == 0x00))) {
 520                         traceState = TRACE_ERROR;  // do not decrypt the next commands
 521                         return 0;
 522                 }
 523
 524                 return 0;
 525         break;
 526
 527         case TRACE_READ_DATA:
 528                 if (len == 18) {
 529                         traceState = TRACE_IDLE;
 530
 531                         if (isBlockTrailer(traceCurBlock)) {
 532                                 memcpy(traceCard + traceCurBlock * 16 + 6, data + 6, 4);
 533                         } else {
 534                                 memcpy(traceCard + traceCurBlock * 16, data, 16);
 535                         }
 536                         if (wantSaveToEmlFile) saveTraceCard();
 537                         return 0;
 538                 } else {
 539                         traceState = TRACE_ERROR;
 540                         return 1;
 541                 }
 542         break;
 543
 544         case TRACE_WRITE_OK:
 545                 if ((len == 1) && (data[0] == 0x0a)) {
 546                         traceState = TRACE_WRITE_DATA;
 547
 548                         return 0;
 549                 } else {
 550                         traceState = TRACE_ERROR;
 551                         return 1;
 552                 }
 553         break;
 554
 555         case TRACE_WRITE_DATA:
 556                 if (len == 18) {
 557                         traceState = TRACE_IDLE;
 558
 559                         memcpy(traceCard + traceCurBlock * 16, data, 16);
 560                         if (wantSaveToEmlFile) saveTraceCard();
 561                         return 0;
 562                 } else {
 563                         traceState = TRACE_ERROR;
 564                         return 1;
 565                 }
 566         break;
 567
 568         case TRACE_AUTH1:
 569                 if (len == 4) {
 570                         traceState = TRACE_AUTH2;
 571                         nt = bytes_to_num(data, 4);
 572                         return 0;
 573                 } else {
 574                         traceState = TRACE_ERROR;
 575                         return 1;
 576                 }
 577         break;
 578
 579         case TRACE_AUTH2:
 580                 if (len == 8) {
 581                         traceState = TRACE_AUTH_OK;
 582
 583                         nr_enc = bytes_to_num(data, 4);
 584                         ar_enc = bytes_to_num(data + 4, 4);
 585                         return 0;
 586                 } else {
 587                         traceState = TRACE_ERROR;
 588                         return 1;
 589                 }
 590         break;
 591
 592         case TRACE_AUTH_OK:
 593                 if (len ==4) {
 594                         traceState = TRACE_IDLE;
 595
 596                         at_enc = bytes_to_num(data, 4);
 597
 598                         //  decode key here)
 599                         ks2 = ar_enc ^ prng_successor(nt, 64);
 600                         ks3 = at_enc ^ prng_successor(nt, 96);
 601                         revstate = lfsr_recovery64(ks2, ks3);
 602                         lfsr_rollback_word(revstate, 0, 0);
 603                         lfsr_rollback_word(revstate, 0, 0);
 604                         lfsr_rollback_word(revstate, nr_enc, 1);
 605                         lfsr_rollback_word(revstate, uid ^ nt, 0);
 606
 607                         crypto1_get_lfsr(revstate, &key);
 608                         printf("Key: %012"llx"\n",key);
 609                         AddLogUint64(logHexFileName, "key: ", key);
 610
 611                         int blockShift = ((traceCurBlock & 0xFC) + 3) * 16;
 612                         if (isBlockEmpty((traceCurBlock & 0xFC) + 3)) memcpy(traceCard + blockShift + 6, trailerAccessBytes, 4);
 613
 614                         if (traceCurKey) {
 615                                 num_to_bytes(key, 6, traceCard + blockShift + 10);
 616                         } else {
 617                                 num_to_bytes(key, 6, traceCard + blockShift);
 618                         }
 619                         if (wantSaveToEmlFile) saveTraceCard();
 620
 621                         if (traceCrypto1) {
 622                                 crypto1_destroy(traceCrypto1);
 623                         }
 624
 625                         // set cryptosystem state
 626                         traceCrypto1 = lfsr_recovery64(ks2, ks3);
 627
 628 //      nt = crypto1_word(traceCrypto1, nt ^ uid, 1) ^ nt;
 629
 630         /*      traceCrypto1 = crypto1_create(key); // key in lfsr
 631                 crypto1_word(traceCrypto1, nt ^ uid, 0);
 632                 crypto1_word(traceCrypto1, ar, 1);
 633                 crypto1_word(traceCrypto1, 0, 0);
 634                 crypto1_word(traceCrypto1, 0, 0);*/
 635
 636                         return 0;
 637                 } else {
 638                         traceState = TRACE_ERROR;
 639                         return 1;
 640                 }
 641         break;
 642
 643         default:
 644                 traceState = TRACE_ERROR;
 645                 return 1;
 646         }
 647
 648         return 0;
 649 }
 650
 651 int tryDecryptWord(uint32_t nt, uint32_t ar_enc, uint32_t at_enc, uint8_t *data, int len){
 652         /*
 653         uint32_t nt;      // tag challenge
 654         uint32_t nr_enc;  // encrypted reader challenge
 655         uint32_t ar_enc;  // encrypted reader response
 656         uint32_t at_enc;  // encrypted tag response
 657         */
 658         struct Crypto1State *pcs = NULL;
 659
 660         ks2 = ar_enc ^ prng_successor(nt, 64);
 661         ks3 = at_enc ^ prng_successor(nt, 96);
 662
 663         PrintAndLog("Decrypting data with:");
 664         PrintAndLog("      nt: %08x",nt);
 665         PrintAndLog("  ar_enc: %08x",ar_enc);
 666         PrintAndLog("  at_enc: %08x",at_enc);
 667         PrintAndLog("\nEncrypted data: [%s]", sprint_hex(data,len) );
 668
 669         pcs = lfsr_recovery64(ks2, ks3);
 670         mf_crypto1_decrypt(pcs, data, len, FALSE);
 671         PrintAndLog("Decrypted data: [%s]", sprint_hex(data,len) );
 672         crypto1_destroy(pcs);
 673         return 0;
 674 }