git.zerfleddert.de Git - proxmark3-svn/blob - client/mifare/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 "mifarehost.h"
  12
  13 #include <inttypes.h>
  14 #include <stdio.h>
  15 #include <stdlib.h>
  16 #include <string.h>
  17 #include <pthread.h>
  18
  19 #include "crapto1/crapto1.h"
  20 #include "comms.h"
  21 #include "usb_cmd.h"
  22 #include "cmdmain.h"
  23 #include "ui.h"
  24 #include "parity.h"
  25 #include "util.h"
  26 #include "iso14443crc.h"
  27 #include "util_posix.h"
  28
  29 #include "mifare.h"
  30 #include "mifare4.h"
  31
  32 // mifare tracer flags used in mfTraceDecode()
  33 #define TRACE_IDLE                                              0x00
  34 #define TRACE_AUTH1                                             0x01
  35 #define TRACE_AUTH2                                             0x02
  36 #define TRACE_AUTH_OK                                   0x03
  37 #define TRACE_READ_DATA                                 0x04
  38 #define TRACE_WRITE_OK                                  0x05
  39 #define TRACE_WRITE_DATA                                0x06
  40 #define TRACE_ERROR                                             0xFF
  41
  42
  43 static int compare_uint64(const void *a, const void *b) {
  44         // didn't work: (the result is truncated to 32 bits)
  45         //return (*(int64_t*)b - *(int64_t*)a);
  46
  47         // better:
  48         if (*(uint64_t*)b == *(uint64_t*)a) return 0;
  49         else if (*(uint64_t*)b < *(uint64_t*)a) return 1;
  50         else return -1;
  51 }
  52
  53
  54 // create the intersection (common members) of two sorted lists. Lists are terminated by -1. Result will be in list1. Number of elements is returned.
  55 static uint32_t intersection(uint64_t *list1, uint64_t *list2)
  56 {
  57         if (list1 == NULL || list2 == NULL) {
  58                 return 0;
  59         }
  60         uint64_t *p1, *p2, *p3;
  61         p1 = p3 = list1;
  62         p2 = list2;
  63
  64         while ( *p1 != -1 && *p2 != -1 ) {
  65                 if (compare_uint64(p1, p2) == 0) {
  66                         *p3++ = *p1++;
  67                         p2++;
  68                 }
  69                 else {
  70                         while (compare_uint64(p1, p2) < 0) ++p1;
  71                         while (compare_uint64(p1, p2) > 0) ++p2;
  72                 }
  73         }
  74         *p3 = -1;
  75         return p3 - list1;
  76 }
  77
  78
  79 // Darkside attack (hf mf mifare)
  80 static uint32_t nonce2key(uint32_t uid, uint32_t nt, uint32_t nr, uint32_t ar, uint64_t par_info, uint64_t ks_info, uint64_t **keys) {
  81         struct Crypto1State *states;
  82         uint32_t i, pos;
  83         uint8_t bt, ks3x[8], par[8][8];
  84         uint64_t key_recovered;
  85         uint64_t *keylist;
  86
  87         // Reset the last three significant bits of the reader nonce
  88         nr &= 0xffffff1f;
  89
  90         for (pos=0; pos<8; pos++) {
  91                 ks3x[7-pos] = (ks_info >> (pos*8)) & 0x0f;
  92                 bt = (par_info >> (pos*8)) & 0xff;
  93                 for (i=0; i<8; i++)     {
  94                                 par[7-pos][i] = (bt >> i) & 0x01;
  95                 }
  96         }
  97
  98         states = lfsr_common_prefix(nr, ar, ks3x, par, (par_info == 0));
  99
 100         if (states == NULL) {
 101                 *keys = NULL;
 102                 return 0;
 103         }
 104
 105         keylist = (uint64_t*)states;
 106
 107         for (i = 0; keylist[i]; i++) {
 108                 lfsr_rollback_word(states+i, uid^nt, 0);
 109                 crypto1_get_lfsr(states+i, &key_recovered);
 110                 keylist[i] = key_recovered;
 111         }
 112         keylist[i] = -1;
 113
 114         *keys = keylist;
 115         return i;
 116 }
 117
 118
 119 int mfDarkside(uint64_t *key) {
 120         uint32_t uid = 0;
 121         uint32_t nt = 0, nr = 0, ar = 0;
 122         uint64_t par_list = 0, ks_list = 0;
 123         uint64_t *keylist = NULL, *last_keylist = NULL;
 124         uint32_t keycount = 0;
 125         int16_t isOK = 0;
 126
 127         UsbCommand c = {CMD_READER_MIFARE, {true, 0, 0}};
 128
 129         // message
 130         printf("-------------------------------------------------------------------------\n");
 131         printf("Executing command. Expected execution time: 25sec on average\n");
 132         printf("Press button on the proxmark3 device to abort both proxmark3 and client.\n");
 133         printf("-------------------------------------------------------------------------\n");
 134
 135
 136         while (true) {
 137                 clearCommandBuffer();
 138                 SendCommand(&c);
 139
 140                 //flush queue
 141                 while (ukbhit()) {
 142                         int c = getchar(); (void) c;
 143                 }
 144
 145                 // wait cycle
 146                 while (true) {
 147                         printf(".");
 148                         fflush(stdout);
 149                         if (ukbhit()) {
 150                                 return -5;
 151                                 break;
 152                         }
 153
 154                         UsbCommand resp;
 155                         if (WaitForResponseTimeout(CMD_ACK, &resp, 1000)) {
 156                                 isOK  = resp.arg[0];
 157                                 if (isOK < 0) {
 158                                         return isOK;
 159                                 }
 160                                 uid = (uint32_t)bytes_to_num(resp.d.asBytes +  0, 4);
 161                                 nt =  (uint32_t)bytes_to_num(resp.d.asBytes +  4, 4);
 162                                 par_list = bytes_to_num(resp.d.asBytes +  8, 8);
 163                                 ks_list = bytes_to_num(resp.d.asBytes +  16, 8);
 164                                 nr = (uint32_t)bytes_to_num(resp.d.asBytes + 24, 4);
 165                                 ar = (uint32_t)bytes_to_num(resp.d.asBytes + 28, 4);
 166                                 break;
 167                         }
 168                 }
 169
 170                 if (par_list == 0 && c.arg[0] == true) {
 171                         PrintAndLog("Parity is all zero. Most likely this card sends NACK on every failed authentication.");
 172                 }
 173                 c.arg[0] = false;
 174
 175                 keycount = nonce2key(uid, nt, nr, ar, par_list, ks_list, &keylist);
 176
 177                 if (keycount == 0) {
 178                         PrintAndLog("Key not found (lfsr_common_prefix list is null). Nt=%08x", nt);
 179                         PrintAndLog("This is expected to happen in 25%% of all cases. Trying again with a different reader nonce...");
 180                         continue;
 181                 }
 182
 183                 if (par_list == 0) {
 184                         qsort(keylist, keycount, sizeof(*keylist), compare_uint64);
 185                         keycount = intersection(last_keylist, keylist);
 186                         if (keycount == 0) {
 187                                 free(last_keylist);
 188                                 last_keylist = keylist;
 189                                 continue;
 190                         }
 191                 }
 192
 193                 if (keycount > 1) {
 194                         PrintAndLog("Found %u possible keys. Trying to authenticate with each of them ...\n", keycount);
 195                 } else {
 196                         PrintAndLog("Found a possible key. Trying to authenticate...\n");
 197                 }
 198
 199                 uint8_t *keys_to_chk = malloc(keycount * 6);
 200                 for (int i = 0; i < keycount; i++) {
 201                         num_to_bytes(keylist[i], 6, keys_to_chk+i);
 202                 }
 203
 204                 *key = -1;
 205                 mfCheckKeys(0, 0, 0, false, keycount, keys_to_chk, key);
 206
 207                 free(keys_to_chk);
 208
 209                 if (*key != -1) {
 210                         free(last_keylist);
 211                         free(keylist);
 212                         break;
 213                 } else {
 214                         PrintAndLog("Authentication failed. Trying again...");
 215                         free(last_keylist);
 216                         last_keylist = keylist;
 217                 }
 218         }
 219
 220         return 0;
 221 }
 222
 223
 224 int mfCheckKeys(uint8_t blockNo, uint8_t keyType, uint16_t timeout14a, bool clear_trace, uint32_t keycnt, uint8_t *keys, uint64_t *found_key) {
 225
 226         bool display_progress = false;
 227         uint64_t start_time = msclock();
 228         uint64_t next_print_time = start_time + 5 * 1000;
 229
 230         if (keycnt > 1000) {
 231                 PrintAndLog("We have %d keys to check. This will take some time!", keycnt);
 232                 PrintAndLog("Press button to abort.");
 233                 display_progress = true;
 234         }
 235
 236         uint32_t max_keys  = (keycnt > (USB_CMD_DATA_SIZE / 6)) ? (USB_CMD_DATA_SIZE / 6) : keycnt;
 237         *found_key = -1;
 238         bool multisectorCheck = false;
 239
 240         for (int i = 0, ii = 0; i < keycnt; i += max_keys) {
 241
 242                 if ((i + max_keys) >= keycnt) {
 243                         max_keys = keycnt - i;
 244                 }
 245
 246                 bool init = (i == 0);
 247                 bool drop_field = (max_keys == keycnt);
 248                 uint8_t flags = clear_trace | multisectorCheck << 1 | init << 2 | drop_field << 3;
 249
 250                 UsbCommand c = {CMD_MIFARE_CHKKEYS, {((blockNo & 0xff) | ((keyType & 0xff) << 8)), flags | timeout14a << 16, max_keys}};
 251                 memcpy(c.d.asBytes, keys + i * 6, max_keys * 6);
 252                 SendCommand(&c);
 253
 254                 UsbCommand resp;
 255                 if (!WaitForResponseTimeout(CMD_ACK, &resp, 3000))
 256                         return 1;
 257
 258                 if ((resp.arg[0] & 0xff) != 0x01) {
 259                         if (((int)resp.arg[1]) < 0) {   // error
 260                                 return (int)resp.arg[1];
 261                         } else {                        // nothing found yet
 262                                 if (display_progress && msclock() >= next_print_time) {
 263                                         float brute_force_per_second = (float)(i - ii) / (float)(msclock() - start_time) * 1000.0;
 264                                         ii = i;
 265                                         start_time = msclock();
 266                                         next_print_time = start_time + 10 * 1000;
 267                                         PrintAndLog(" %8d keys left | %5.1f keys/sec | worst case %6.1f seconds remaining", keycnt - i, brute_force_per_second, (keycnt-i)/brute_force_per_second);
 268                                 }
 269                         }
 270                 } else {                                                        // success
 271                         *found_key = bytes_to_num(resp.d.asBytes, 6);
 272                         return 0;
 273                 }
 274         }
 275
 276         return 2;       // nothing found
 277 }
 278
 279
 280 int mfCheckKeysSec(uint8_t sectorCnt, uint8_t keyType, uint16_t timeout14a, bool clear_trace, bool init, bool drop_field, uint8_t keycnt, uint8_t * keyBlock, sector_t * e_sector) {
 281
 282         uint8_t keyPtr = 0;
 283
 284         if (e_sector == NULL)
 285                 return -1;
 286
 287         bool multisectorCheck = true;
 288         uint8_t flags = clear_trace | multisectorCheck << 1 | init << 2 | drop_field << 3;
 289
 290         UsbCommand c = {CMD_MIFARE_CHKKEYS, {((sectorCnt & 0xff) | ((keyType & 0xff) << 8)), flags | timeout14a << 16, keycnt}};
 291         memcpy(c.d.asBytes, keyBlock, 6 * keycnt);
 292         SendCommand(&c);
 293
 294         UsbCommand resp;
 295         if (!WaitForResponseTimeoutW(CMD_ACK, &resp, MAX(3000, 1000 + 13 * sectorCnt * keycnt * (keyType == 2 ? 2 : 1)), false)) return 1; // timeout: 13 ms / fail auth
 296         if ((resp.arg[0] & 0xff) != 0x01) return 2;
 297
 298         bool foundAKey = false;
 299         for(int sec = 0; sec < sectorCnt; sec++){
 300                 for(int keyAB = 0; keyAB < 2; keyAB++){
 301                         keyPtr = *(resp.d.asBytes + keyAB * 40 + sec);
 302                         if (keyPtr){
 303                                 e_sector[sec].foundKey[keyAB] = true;
 304                                 e_sector[sec].Key[keyAB] = bytes_to_num(keyBlock + (keyPtr - 1) * 6, 6);
 305                                 foundAKey = true;
 306                         }
 307                 }
 308         }
 309         return foundAKey ? 0 : 3;
 310 }
 311
 312 // Compare 16 Bits out of cryptostate
 313 int Compare16Bits(const void * a, const void * b) {
 314         if ((*(uint64_t*)b & 0x00ff000000ff0000) == (*(uint64_t*)a & 0x00ff000000ff0000)) return 0;
 315         else if ((*(uint64_t*)b & 0x00ff000000ff0000) > (*(uint64_t*)a & 0x00ff000000ff0000)) return 1;
 316         else return -1;
 317 }
 318
 319 typedef
 320         struct {
 321                 union {
 322                         struct Crypto1State *slhead;
 323                         uint64_t *keyhead;
 324                 } head;
 325                 union {
 326                         struct Crypto1State *sltail;
 327                         uint64_t *keytail;
 328                 } tail;
 329                 uint32_t len;
 330                 uint32_t uid;
 331                 uint32_t blockNo;
 332                 uint32_t keyType;
 333                 uint32_t nt_enc;
 334                 uint32_t ks1;
 335         } StateList_t;
 336
 337
 338 // wrapper function for multi-threaded lfsr_recovery32
 339 void
 340 #ifdef __has_attribute
 341 #if __has_attribute(force_align_arg_pointer)
 342 __attribute__((force_align_arg_pointer))
 343 #endif
 344 #endif
 345 *nested_worker_thread(void *arg) {
 346         struct Crypto1State *p1;
 347         StateList_t *statelist = arg;
 348
 349         statelist->head.slhead = lfsr_recovery32(statelist->ks1, statelist->nt_enc ^ statelist->uid);
 350         for (p1 = statelist->head.slhead; *(uint64_t *)p1 != 0; p1++);
 351         statelist->len = p1 - statelist->head.slhead;
 352         statelist->tail.sltail = --p1;
 353         qsort(statelist->head.slhead, statelist->len, sizeof(uint64_t), Compare16Bits);
 354
 355         return statelist->head.slhead;
 356 }
 357
 358
 359 int mfnested(uint8_t blockNo, uint8_t keyType, uint16_t timeout14a, uint8_t *key, uint8_t trgBlockNo, uint8_t trgKeyType, uint8_t *resultKey, bool calibrate) {
 360         uint32_t i;
 361         uint32_t uid;
 362         UsbCommand resp;
 363
 364         int num_unique_nonces;
 365
 366         StateList_t statelists[2];
 367         struct Crypto1State *p1, *p2, *p3, *p4;
 368
 369         uint8_t *keyBlock = NULL;
 370         uint64_t key64;
 371
 372         int isOK = 1;
 373
 374         // flush queue
 375         (void)WaitForResponseTimeout(CMD_ACK,NULL,100);
 376
 377         UsbCommand c = {CMD_MIFARE_NESTED, {blockNo + keyType * 0x100, trgBlockNo + trgKeyType * 0x100, calibrate}};
 378         memcpy(c.d.asBytes, key, 6);
 379         SendCommand(&c);
 380
 381         if (!WaitForResponseTimeout(CMD_ACK, &resp, 2500)) {
 382                 // some cards can cause it to get stuck in a loop, so break out of it
 383                 UsbCommand c = {CMD_PING};
 384                 SendCommand(&c);
 385                 (void)WaitForResponseTimeout(CMD_ACK,NULL,500);
 386                 return -1;
 387         }
 388
 389         if (resp.arg[0]) {
 390                 return resp.arg[0];  // error during nested
 391         }
 392
 393         memcpy(&uid, resp.d.asBytes, 4);
 394         PrintAndLog("uid:%08x trgbl=%d trgkey=%x", uid, (uint16_t)resp.arg[2] & 0xff, (uint16_t)resp.arg[2] >> 8);
 395
 396         for (i = 0; i < 2; i++) {
 397                 statelists[i].blockNo = resp.arg[2] & 0xff;
 398                 statelists[i].keyType = (resp.arg[2] >> 8) & 0xff;
 399                 statelists[i].uid = uid;
 400                 memcpy(&statelists[i].nt_enc,  (void *)(resp.d.asBytes + 4 + i * 8 + 0), 4);
 401                 memcpy(&statelists[i].ks1, (void *)(resp.d.asBytes + 4 + i * 8 + 4), 4);
 402         }
 403
 404         uint32_t authentication_timeout;
 405         memcpy(&authentication_timeout, resp.d.asBytes + 20, 4);
 406         PrintAndLog("Setting authentication timeout to %" PRIu32 "us", authentication_timeout * 1000 / 106);
 407
 408         if (statelists[0].nt_enc == statelists[1].nt_enc && statelists[0].ks1 == statelists[1].ks1)
 409                 num_unique_nonces = 1;
 410         else
 411                 num_unique_nonces = 2;
 412
 413         // calc keys
 414
 415         pthread_t thread_id[2];
 416
 417         // create and run worker threads
 418         for (i = 0; i < 2; i++) {
 419                 pthread_create(thread_id + i, NULL, nested_worker_thread, &statelists[i]);
 420         }
 421
 422         // wait for threads to terminate:
 423         for (i = 0; i < 2; i++) {
 424                 pthread_join(thread_id[i], (void*)&statelists[i].head.slhead);
 425         }
 426
 427
 428         // the first 16 Bits of the cryptostate already contain part of our key.
 429         // Create the intersection of the two lists based on these 16 Bits and
 430         // roll back the cryptostate
 431         p1 = p3 = statelists[0].head.slhead;
 432         p2 = p4 = statelists[1].head.slhead;
 433         while (p1 <= statelists[0].tail.sltail && p2 <= statelists[1].tail.sltail) {
 434                 if (Compare16Bits(p1, p2) == 0) {
 435                         struct Crypto1State savestate, *savep = &savestate;
 436                         savestate = *p1;
 437                         while(Compare16Bits(p1, savep) == 0 && p1 <= statelists[0].tail.sltail) {
 438                                 *p3 = *p1;
 439                                 lfsr_rollback_word(p3, statelists[0].nt_enc ^ statelists[0].uid, 0);
 440                                 p3++;
 441                                 p1++;
 442                         }
 443                         savestate = *p2;
 444                         while(Compare16Bits(p2, savep) == 0 && p2 <= statelists[1].tail.sltail) {
 445                                 *p4 = *p2;
 446                                 lfsr_rollback_word(p4, statelists[1].nt_enc ^ statelists[1].uid, 0);
 447                                 p4++;
 448                                 p2++;
 449                         }
 450                 }
 451                 else {
 452                         while (Compare16Bits(p1, p2) == -1) p1++;
 453                         while (Compare16Bits(p1, p2) == 1) p2++;
 454                 }
 455         }
 456         *(uint64_t*)p3 = -1;
 457         *(uint64_t*)p4 = -1;
 458         statelists[0].len = p3 - statelists[0].head.slhead;
 459         statelists[1].len = p4 - statelists[1].head.slhead;
 460         statelists[0].tail.sltail=--p3;
 461         statelists[1].tail.sltail=--p4;
 462
 463         for (i = 0; i < 2; i++) {
 464                 PrintAndLog("statelist %d: length:%d block:%02d keytype:%d nt_enc:%08X ks1:%08X", i, statelists[i].len, statelists[i].blockNo, statelists[i].keyType, statelists[i].nt_enc, statelists[i].ks1);
 465         }
 466
 467         // the statelists now contain possible keys. The key we are searching for must be in the
 468         // intersection of both lists. Create the intersection:
 469         qsort(statelists[0].head.keyhead, statelists[0].len, sizeof(uint64_t), compare_uint64);
 470
 471         if (num_unique_nonces > 1) {
 472                 qsort(statelists[1].head.keyhead, statelists[1].len, sizeof(uint64_t), compare_uint64);
 473                 statelists[0].len = intersection(statelists[0].head.keyhead, statelists[1].head.keyhead);
 474         }
 475         else {
 476                 PrintAndLog("Nonce 1 and 2 are the same!");
 477         }
 478
 479         uint32_t num_keys = statelists[0].len;
 480         keyBlock = calloc(num_keys, 6);
 481         if (keyBlock == NULL) {
 482                 free(statelists[0].head.slhead);
 483                 free(statelists[1].head.slhead);
 484                 return -4;
 485         }
 486
 487         for (i = 0; i < num_keys; i++) {
 488                 crypto1_get_lfsr(statelists[0].head.slhead + i, &key64);
 489                 num_to_bytes(key64, 6, keyBlock + i*6);
 490         }
 491
 492         // The list may still contain several key candidates. Test each of them with mfCheckKeys
 493         isOK = mfCheckKeys(statelists[0].blockNo, statelists[0].keyType, authentication_timeout, true, num_keys, keyBlock, &key64);
 494
 495         if (isOK == 0) {     // success, key found
 496                 num_to_bytes(key64, 6, resultKey);
 497         }
 498
 499         if (isOK == 1) {     // timeout
 500                 isOK = -1;
 501         }
 502
 503         free(statelists[0].head.slhead);
 504         free(statelists[1].head.slhead);
 505         free(keyBlock);
 506
 507         return isOK;
 508 }
 509
 510 // MIFARE
 511 int mfReadSector(uint8_t sectorNo, uint8_t keyType, uint8_t *key, uint8_t *data) {
 512
 513     UsbCommand c = {CMD_MIFARE_READSC, {sectorNo, keyType, 0}};
 514     memcpy(c.d.asBytes, key, 6);
 515     clearCommandBuffer();
 516     SendCommand(&c);
 517
 518     UsbCommand resp;
 519     if (WaitForResponseTimeout(CMD_ACK, &resp, 1500)) {
 520         uint8_t isOK  = resp.arg[0] & 0xff;
 521
 522         if (isOK) {
 523             memcpy(data, resp.d.asBytes, mfNumBlocksPerSector(sectorNo) * 16);
 524             return 0;
 525         } else {
 526             return 1;
 527         }
 528     } else {
 529         PrintAndLogEx(ERR, "Command execute timeout");
 530         return 2;
 531     }
 532
 533     return 0;
 534 }
 535
 536 // EMULATOR
 537
 538 int mfEmlGetMem(uint8_t *data, int blockNum, int blocksCount) {
 539         UsbCommand c = {CMD_MIFARE_EML_MEMGET, {blockNum, blocksCount, 0}};
 540         SendCommand(&c);
 541
 542   UsbCommand resp;
 543         if (!WaitForResponseTimeout(CMD_ACK,&resp,1500)) return 1;
 544         memcpy(data, resp.d.asBytes, blocksCount * 16);
 545         return 0;
 546 }
 547
 548 int mfEmlSetMem(uint8_t *data, int blockNum, int blocksCount) {
 549         UsbCommand c = {CMD_MIFARE_EML_MEMSET, {blockNum, blocksCount, 0}};
 550         memcpy(c.d.asBytes, data, blocksCount * 16);
 551         SendCommand(&c);
 552         return 0;
 553 }
 554
 555 // "MAGIC" CARD
 556
 557 int mfCGetBlock(uint8_t blockNo, uint8_t *data, uint8_t params) {
 558         uint8_t isOK = 0;
 559
 560         UsbCommand c = {CMD_MIFARE_CGETBLOCK, {params, 0, blockNo}};
 561         SendCommand(&c);
 562
 563         UsbCommand resp;
 564         if (WaitForResponseTimeout(CMD_ACK,&resp,1500)) {
 565                 isOK  = resp.arg[0] & 0xff;
 566                 memcpy(data, resp.d.asBytes, 16);
 567                 if (!isOK) return 2;
 568         } else {
 569                 PrintAndLog("Command execute timeout");
 570                 return 1;
 571         }
 572         return 0;
 573 }
 574
 575 int mfCSetBlock(uint8_t blockNo, uint8_t *data, uint8_t *uid, bool wantWipe, uint8_t params) {
 576
 577         uint8_t isOK = 0;
 578         UsbCommand c = {CMD_MIFARE_CSETBLOCK, {wantWipe, params & (0xFE | (uid == NULL ? 0:1)), blockNo}};
 579         memcpy(c.d.asBytes, data, 16);
 580         SendCommand(&c);
 581
 582         UsbCommand resp;
 583         if (WaitForResponseTimeout(CMD_ACK, &resp, 1500)) {
 584                 isOK  = resp.arg[0] & 0xff;
 585                 if (uid != NULL)
 586                         memcpy(uid, resp.d.asBytes, 4);
 587                 if (!isOK)
 588                         return 2;
 589         } else {
 590                 PrintAndLog("Command execute timeout");
 591                 return 1;
 592         }
 593
 594         return 0;
 595 }
 596
 597 int mfCWipe(uint32_t numSectors, bool gen1b, bool wantWipe, bool wantFill) {
 598         uint8_t isOK = 0;
 599         uint8_t cmdParams = wantWipe + wantFill * 0x02 + gen1b * 0x04;
 600         UsbCommand c = {CMD_MIFARE_CWIPE, {numSectors, cmdParams, 0}};
 601         SendCommand(&c);
 602
 603         UsbCommand resp;
 604         WaitForResponse(CMD_ACK,&resp);
 605         isOK  = resp.arg[0] & 0xff;
 606
 607         return isOK;
 608 }
 609
 610 int mfCSetUID(uint8_t *uid, uint8_t *atqa, uint8_t *sak, uint8_t *oldUID) {
 611         uint8_t oldblock0[16] = {0x00};
 612         uint8_t block0[16] = {0x00};
 613         int gen = 0, res;
 614
 615         gen = mfCIdentify();
 616
 617         /* generation 1a magic card by default */
 618         uint8_t cmdParams = CSETBLOCK_SINGLE_OPER;
 619         if (gen == 2) {
 620                 /* generation 1b magic card */
 621                 cmdParams = CSETBLOCK_SINGLE_OPER | CSETBLOCK_MAGIC_1B;
 622         }
 623
 624         res = mfCGetBlock(0, oldblock0, cmdParams);
 625
 626         if (res == 0) {
 627                 memcpy(block0, oldblock0, 16);
 628                 PrintAndLog("old block 0:  %s", sprint_hex(block0,16));
 629         } else {
 630                 PrintAndLog("Couldn't get old data. Will write over the last bytes of Block 0.");
 631         }
 632
 633         // fill in the new values
 634         // UID
 635         memcpy(block0, uid, 4);
 636         // Mifare UID BCC
 637         block0[4] = block0[0] ^ block0[1] ^ block0[2] ^ block0[3];
 638         // mifare classic SAK(byte 5) and ATQA(byte 6 and 7, reversed)
 639         if (sak != NULL)
 640                 block0[5] = sak[0];
 641         if (atqa != NULL) {
 642                 block0[6] = atqa[1];
 643                 block0[7] = atqa[0];
 644         }
 645         PrintAndLog("new block 0:  %s", sprint_hex(block0, 16));
 646
 647         res = mfCSetBlock(0, block0, oldUID, false, cmdParams);
 648         if (res) {
 649                 PrintAndLog("Can't set block 0. Error: %d", res);
 650                 return res;
 651         }
 652
 653         return 0;
 654 }
 655
 656 int mfCIdentify() {
 657         UsbCommand c = {CMD_MIFARE_CIDENT, {0, 0, 0}};
 658         SendCommand(&c);
 659         UsbCommand resp;
 660         WaitForResponse(CMD_ACK,&resp);
 661
 662         uint8_t isGeneration = resp.arg[0] & 0xff;
 663         switch( isGeneration ){
 664                 case 1: PrintAndLog("Chinese magic backdoor commands (GEN 1a) detected"); break;
 665                 case 2: PrintAndLog("Chinese magic backdoor command (GEN 1b) detected"); break;
 666                 default: PrintAndLog("No chinese magic backdoor command detected"); break;
 667         }
 668
 669         return (int) isGeneration;
 670 }
 671
 672
 673 // SNIFFER
 674
 675 // constants
 676 static uint8_t trailerAccessBytes[4] = {0x08, 0x77, 0x8F, 0x00};
 677
 678 // variables
 679 char logHexFileName[FILE_PATH_SIZE] = {0x00};
 680 static uint8_t traceCard[4096] = {0x00};
 681 static char traceFileName[FILE_PATH_SIZE] = {0x00};
 682 static int traceState = TRACE_IDLE;
 683 static uint8_t traceCurBlock = 0;
 684 static uint8_t traceCurKey = 0;
 685
 686 struct Crypto1State *traceCrypto1 = NULL;
 687
 688 struct Crypto1State *revstate;
 689 uint64_t lfsr;
 690 uint64_t ui64Key;
 691 uint32_t ks2;
 692 uint32_t ks3;
 693
 694 uint32_t uid;       // serial number
 695 uint32_t nt;        // tag challenge
 696 uint32_t nt_enc;    // encrypted tag challenge
 697 uint8_t nt_enc_par; // encrypted tag challenge parity
 698 uint32_t nr_enc;    // encrypted reader challenge
 699 uint32_t ar_enc;    // encrypted reader response
 700 uint8_t ar_enc_par; // encrypted reader response parity
 701 uint32_t at_enc;    // encrypted tag response
 702 uint8_t at_enc_par; // encrypted tag response parity
 703
 704 int isTraceCardEmpty(void) {
 705         return ((traceCard[0] == 0) && (traceCard[1] == 0) && (traceCard[2] == 0) && (traceCard[3] == 0));
 706 }
 707
 708 int isBlockEmpty(int blockN) {
 709         for (int i = 0; i < 16; i++)
 710                 if (traceCard[blockN * 16 + i] != 0) return 0;
 711
 712         return 1;
 713 }
 714
 715 int isBlockTrailer(int blockN) {
 716  return ((blockN & 0x03) == 0x03);
 717 }
 718
 719 int saveTraceCard(void) {
 720         FILE * f;
 721
 722         if ((!strlen(traceFileName)) || (isTraceCardEmpty())) return 0;
 723
 724         f = fopen(traceFileName, "w+");
 725         if ( !f ) return 1;
 726
 727         for (int i = 0; i < 64; i++) {  // blocks
 728                 for (int j = 0; j < 16; j++)  // bytes
 729                         fprintf(f, "%02x", *(traceCard + i * 16 + j));
 730                 if (i < 63)
 731                         fprintf(f,"\n");
 732         }
 733         fclose(f);
 734         return 0;
 735 }
 736
 737 int loadTraceCard(uint8_t *tuid) {
 738         FILE * f;
 739         char buf[64] = {0x00};
 740         uint8_t buf8[64] = {0x00};
 741         int i, blockNum;
 742
 743         if (!isTraceCardEmpty())
 744                 saveTraceCard();
 745
 746         memset(traceCard, 0x00, 4096);
 747         memcpy(traceCard, tuid + 3, 4);
 748
 749         FillFileNameByUID(traceFileName, tuid, ".eml", 7);
 750
 751         f = fopen(traceFileName, "r");
 752         if (!f) return 1;
 753
 754         blockNum = 0;
 755
 756         while(!feof(f)){
 757
 758                 memset(buf, 0, sizeof(buf));
 759                 if (fgets(buf, sizeof(buf), f) == NULL) {
 760                         PrintAndLog("File reading error.");
 761                         fclose(f);
 762                         return 2;
 763         }
 764
 765                 if (strlen(buf) < 32){
 766                         if (feof(f)) break;
 767                         PrintAndLog("File content error. Block data must include 32 HEX symbols");
 768                         fclose(f);
 769                         return 2;
 770                 }
 771                 for (i = 0; i < 32; i += 2)
 772                         sscanf(&buf[i], "%02x", (unsigned int *)&buf8[i / 2]);
 773
 774                 memcpy(traceCard + blockNum * 16, buf8, 16);
 775
 776                 blockNum++;
 777         }
 778         fclose(f);
 779
 780         return 0;
 781 }
 782
 783 int mfTraceInit(uint8_t *tuid, uint8_t *atqa, uint8_t sak, bool wantSaveToEmlFile) {
 784
 785         if (traceCrypto1)
 786                 crypto1_destroy(traceCrypto1);
 787
 788         traceCrypto1 = NULL;
 789
 790         if (wantSaveToEmlFile)
 791                 loadTraceCard(tuid);
 792
 793         traceCard[4] = traceCard[0] ^ traceCard[1] ^ traceCard[2] ^ traceCard[3];
 794         traceCard[5] = sak;
 795         memcpy(&traceCard[6], atqa, 2);
 796         traceCurBlock = 0;
 797         uid = bytes_to_num(tuid + 3, 4);
 798
 799         traceState = TRACE_IDLE;
 800
 801         return 0;
 802 }
 803
 804 void mf_crypto1_decrypt(struct Crypto1State *pcs, uint8_t *data, int len, bool isEncrypted){
 805         uint8_t bt = 0;
 806         int i;
 807
 808         if (len != 1) {
 809                 for (i = 0; i < len; i++)
 810                         data[i] = crypto1_byte(pcs, 0x00, isEncrypted) ^ data[i];
 811         } else {
 812                 bt = 0;
 813                 for (i = 0; i < 4; i++)
 814                         bt |= (crypto1_bit(pcs, 0, isEncrypted) ^ BIT(data[0], i)) << i;
 815
 816                 data[0] = bt;
 817         }
 818         return;
 819 }
 820
 821 bool NTParityCheck(uint32_t ntx) {
 822         if (
 823                 (oddparity8(ntx >> 8 & 0xff) ^ (ntx & 0x01) ^ ((nt_enc_par >> 5) & 0x01) ^ (nt_enc & 0x01)) ||
 824                 (oddparity8(ntx >> 16 & 0xff) ^ (ntx >> 8 & 0x01) ^ ((nt_enc_par >> 6) & 0x01) ^ (nt_enc >> 8 & 0x01)) ||
 825                 (oddparity8(ntx >> 24 & 0xff) ^ (ntx >> 16 & 0x01) ^ ((nt_enc_par >> 7) & 0x01) ^ (nt_enc >> 16 & 0x01))
 826                 )
 827                 return false;
 828
 829         uint32_t ar = prng_successor(ntx, 64);
 830         if (
 831                 (oddparity8(ar >> 8 & 0xff) ^ (ar & 0x01) ^ ((ar_enc_par >> 5) & 0x01) ^ (ar_enc & 0x01)) ||
 832                 (oddparity8(ar >> 16 & 0xff) ^ (ar >> 8 & 0x01) ^ ((ar_enc_par >> 6) & 0x01) ^ (ar_enc >> 8 & 0x01)) ||
 833                 (oddparity8(ar >> 24 & 0xff) ^ (ar >> 16 & 0x01) ^ ((ar_enc_par >> 7) & 0x01) ^ (ar_enc >> 16 & 0x01))
 834                 )
 835                 return false;
 836
 837         uint32_t at = prng_successor(ntx, 96);
 838         if (
 839                 (oddparity8(ar & 0xff) ^ (at >> 24 & 0x01) ^ ((ar_enc_par >> 4) & 0x01) ^ (at_enc >> 24 & 0x01)) ||
 840                 (oddparity8(at >> 8 & 0xff) ^ (at & 0x01) ^ ((at_enc_par >> 5) & 0x01) ^ (at_enc & 0x01)) ||
 841                 (oddparity8(at >> 16 & 0xff) ^ (at >> 8 & 0x01) ^ ((at_enc_par >> 6) & 0x01) ^ (at_enc >> 8 & 0x01)) ||
 842                 (oddparity8(at >> 24 & 0xff) ^ (at >> 16 & 0x01) ^ ((at_enc_par >> 7) & 0x01) ^ (at_enc >> 16 & 0x01))
 843                 )
 844                 return false;
 845
 846         return true;
 847 }
 848
 849
 850 int mfTraceDecode(uint8_t *data_src, int len, uint8_t parity, bool wantSaveToEmlFile) {
 851         uint8_t data[64];
 852
 853         if (traceState == TRACE_ERROR) return 1;
 854         if (len > 64) {
 855                 traceState = TRACE_ERROR;
 856                 return 1;
 857         }
 858
 859         memcpy(data, data_src, len);
 860         if ((traceCrypto1) && ((traceState == TRACE_IDLE) || (traceState > TRACE_AUTH_OK))) {
 861                 mf_crypto1_decrypt(traceCrypto1, data, len, 0);
 862                 uint8_t parity[16];
 863                 oddparitybuf(data, len, parity);
 864                 PrintAndLog("dec> %s [%s]", sprint_hex(data, len), printBitsPar(parity, len));
 865                 AddLogHex(logHexFileName, "dec> ", data, len);
 866         }
 867
 868         switch (traceState) {
 869         case TRACE_IDLE:
 870                 // check packet crc16!
 871                 if ((len >= 4) && (!CheckCrc14443(CRC_14443_A, data, len))) {
 872                         PrintAndLog("dec> CRC ERROR!!!");
 873                         AddLogLine(logHexFileName, "dec> ", "CRC ERROR!!!");
 874                         traceState = TRACE_ERROR;  // do not decrypt the next commands
 875                         return 1;
 876                 }
 877
 878                 // AUTHENTICATION
 879                 if ((len ==4) && ((data[0] == 0x60) || (data[0] == 0x61))) {
 880                         traceState = TRACE_AUTH1;
 881                         traceCurBlock = data[1];
 882                         traceCurKey = data[0] == 60 ? 1:0;
 883                         return 0;
 884                 }
 885
 886                 // READ
 887                 if ((len ==4) && ((data[0] == 0x30))) {
 888                         traceState = TRACE_READ_DATA;
 889                         traceCurBlock = data[1];
 890                         return 0;
 891                 }
 892
 893                 // WRITE
 894                 if ((len ==4) && ((data[0] == 0xA0))) {
 895                         traceState = TRACE_WRITE_OK;
 896                         traceCurBlock = data[1];
 897                         return 0;
 898                 }
 899
 900                 // HALT
 901                 if ((len ==4) && ((data[0] == 0x50) && (data[1] == 0x00))) {
 902                         traceState = TRACE_ERROR;  // do not decrypt the next commands
 903                         return 0;
 904                 }
 905
 906                 return 0;
 907         break;
 908
 909         case TRACE_READ_DATA:
 910                 if (len == 18) {
 911                         traceState = TRACE_IDLE;
 912
 913                         if (isBlockTrailer(traceCurBlock)) {
 914                                 memcpy(traceCard + traceCurBlock * 16 + 6, data + 6, 4);
 915                         } else {
 916                                 memcpy(traceCard + traceCurBlock * 16, data, 16);
 917                         }
 918                         if (wantSaveToEmlFile) saveTraceCard();
 919                         return 0;
 920                 } else {
 921                         traceState = TRACE_ERROR;
 922                         return 1;
 923                 }
 924         break;
 925
 926         case TRACE_WRITE_OK:
 927                 if ((len == 1) && (data[0] == 0x0a)) {
 928                         traceState = TRACE_WRITE_DATA;
 929
 930                         return 0;
 931                 } else {
 932                         traceState = TRACE_ERROR;
 933                         return 1;
 934                 }
 935         break;
 936
 937         case TRACE_WRITE_DATA:
 938                 if (len == 18) {
 939                         traceState = TRACE_IDLE;
 940
 941                         memcpy(traceCard + traceCurBlock * 16, data, 16);
 942                         if (wantSaveToEmlFile) saveTraceCard();
 943                         return 0;
 944                 } else {
 945                         traceState = TRACE_ERROR;
 946                         return 1;
 947                 }
 948         break;
 949
 950         case TRACE_AUTH1:
 951                 if (len == 4) {
 952                         traceState = TRACE_AUTH2;
 953                         if (!traceCrypto1) {
 954                                 nt = bytes_to_num(data, 4);
 955                         } else {
 956                                 nt_enc = bytes_to_num(data, 4);
 957                                 nt_enc_par = parity;
 958                         }
 959                         return 0;
 960                 } else {
 961                         traceState = TRACE_ERROR;
 962                         return 1;
 963                 }
 964         break;
 965
 966         case TRACE_AUTH2:
 967                 if (len == 8) {
 968                         traceState = TRACE_AUTH_OK;
 969
 970                         nr_enc = bytes_to_num(data, 4);
 971                         ar_enc = bytes_to_num(data + 4, 4);
 972                         ar_enc_par = parity << 4;
 973                         return 0;
 974                 } else {
 975                         traceState = TRACE_ERROR;
 976                         return 1;
 977                 }
 978         break;
 979
 980         case TRACE_AUTH_OK:
 981                 if (len ==4) {
 982                         traceState = TRACE_IDLE;
 983
 984                         at_enc = bytes_to_num(data, 4);
 985                         at_enc_par = parity;
 986                         if (!traceCrypto1) {
 987
 988                                 //  decode key here)
 989                                 ks2 = ar_enc ^ prng_successor(nt, 64);
 990                                 ks3 = at_enc ^ prng_successor(nt, 96);
 991                                 revstate = lfsr_recovery64(ks2, ks3);
 992                                 lfsr_rollback_word(revstate, 0, 0);
 993                                 lfsr_rollback_word(revstate, 0, 0);
 994                                 lfsr_rollback_word(revstate, nr_enc, 1);
 995                                 lfsr_rollback_word(revstate, uid ^ nt, 0);
 996
 997                                 crypto1_get_lfsr(revstate, &lfsr);
 998                                 crypto1_destroy(revstate);
 999                                 ui64Key = lfsr;
1000                                 printf("key> probable key:%x%x Prng:%s ks2:%08x ks3:%08x\n",
1001                                         (unsigned int)((lfsr & 0xFFFFFFFF00000000) >> 32), (unsigned int)(lfsr & 0xFFFFFFFF),
1002                                         validate_prng_nonce(nt) ? "WEAK": "HARDEND",
1003                                         ks2,
1004                                         ks3);
1005                                 AddLogUint64(logHexFileName, "key> ", lfsr);
1006                         } else {
1007                                 if (validate_prng_nonce(nt)) {
1008                                         struct Crypto1State *pcs;
1009                                         pcs = crypto1_create(ui64Key);
1010                                         uint32_t nt1 = crypto1_word(pcs, nt_enc ^ uid, 1) ^ nt_enc;
1011                                         uint32_t ar = prng_successor(nt1, 64);
1012                                         uint32_t at = prng_successor(nt1, 96);
1013                                         printf("key> nested auth uid: %08x nt: %08x nt_parity: %s ar: %08x at: %08x\n", uid, nt1, printBitsPar(&nt_enc_par, 4), ar, at);
1014                                         uint32_t nr1 = crypto1_word(pcs, nr_enc, 1) ^ nr_enc;
1015                                         uint32_t ar1 = crypto1_word(pcs, 0, 0) ^ ar_enc;
1016                                         uint32_t at1 = crypto1_word(pcs, 0, 0) ^ at_enc;
1017                                         crypto1_destroy(pcs);
1018                                         printf("key> the same key test. nr1: %08x ar1: %08x at1: %08x \n", nr1, ar1, at1);
1019
1020                                         if (NTParityCheck(nt1))
1021                                                 printf("key> the same key test OK. key=%x%x\n", (unsigned int)((ui64Key & 0xFFFFFFFF00000000) >> 32), (unsigned int)(ui64Key & 0xFFFFFFFF));
1022                                         else
1023                                                 printf("key> the same key test. check nt parity error.\n");
1024
1025                                         uint32_t ntc = prng_successor(nt, 90);
1026                                         uint32_t ntx = 0;
1027                                         int ntcnt = 0;
1028                                         for (int i = 0; i < 16383; i++) {
1029                                                 ntc = prng_successor(ntc, 1);
1030                                                 if (NTParityCheck(ntc)){
1031                                                         if (!ntcnt)
1032                                                                 ntx = ntc;
1033                                                         ntcnt++;
1034                                                 }
1035                                         }
1036                                         if (ntcnt)
1037                                                 printf("key> nt candidate=%08x nonce distance=%d candidates count=%d\n", ntx, nonce_distance(nt, ntx), ntcnt);
1038                                         else
1039                                                 printf("key> don't have any nt candidate( \n");
1040
1041                                         nt = ntx;
1042                                         ks2 = ar_enc ^ prng_successor(ntx, 64);
1043                                         ks3 = at_enc ^ prng_successor(ntx, 96);
1044
1045                                         // decode key
1046                                         revstate = lfsr_recovery64(ks2, ks3);
1047                                         lfsr_rollback_word(revstate, 0, 0);
1048                                         lfsr_rollback_word(revstate, 0, 0);
1049                                         lfsr_rollback_word(revstate, nr_enc, 1);
1050                                         lfsr_rollback_word(revstate, uid ^ nt, 0);
1051
1052                                         crypto1_get_lfsr(revstate, &lfsr);
1053                                         crypto1_destroy(revstate);
1054                                         ui64Key = lfsr;
1055                                         printf("key> probable key:%x%x  ks2:%08x ks3:%08x\n",
1056                                                 (unsigned int)((lfsr & 0xFFFFFFFF00000000) >> 32), (unsigned int)(lfsr & 0xFFFFFFFF),
1057                                                 ks2,
1058                                                 ks3);
1059                                         AddLogUint64(logHexFileName, "key> ", lfsr);
1060                                 } else {
1061                                         printf("key> hardnested not implemented!\n");
1062
1063                                         crypto1_destroy(traceCrypto1);
1064
1065                                         // not implemented
1066                                         traceState = TRACE_ERROR;
1067                                 }
1068                         }
1069
1070                         int blockShift = ((traceCurBlock & 0xFC) + 3) * 16;
1071                         if (isBlockEmpty((traceCurBlock & 0xFC) + 3)) memcpy(traceCard + blockShift + 6, trailerAccessBytes, 4);
1072
1073                         if (traceCurKey) {
1074                                 num_to_bytes(lfsr, 6, traceCard + blockShift + 10);
1075                         } else {
1076                                 num_to_bytes(lfsr, 6, traceCard + blockShift);
1077                         }
1078                         if (wantSaveToEmlFile) saveTraceCard();
1079
1080                         if (traceCrypto1) {
1081                                 crypto1_destroy(traceCrypto1);
1082                         }
1083
1084                         // set cryptosystem state
1085                         traceCrypto1 = lfsr_recovery64(ks2, ks3);
1086                         return 0;
1087                 } else {
1088                         traceState = TRACE_ERROR;
1089                         return 1;
1090                 }
1091         break;
1092
1093         default:
1094                 traceState = TRACE_ERROR;
1095                 return 1;
1096         }
1097
1098         return 0;
1099 }
1100
1101 // DECODING
1102
1103 int tryDecryptWord(uint32_t nt, uint32_t ar_enc, uint32_t at_enc, uint8_t *data, int len){
1104         /*
1105         uint32_t nt;      // tag challenge
1106         uint32_t ar_enc;  // encrypted reader response
1107         uint32_t at_enc;  // encrypted tag response
1108         */
1109         if (traceCrypto1) {
1110                 crypto1_destroy(traceCrypto1);
1111         }
1112         ks2 = ar_enc ^ prng_successor(nt, 64);
1113         ks3 = at_enc ^ prng_successor(nt, 96);
1114         traceCrypto1 = lfsr_recovery64(ks2, ks3);
1115
1116         mf_crypto1_decrypt(traceCrypto1, data, len, 0);
1117
1118         PrintAndLog("Decrypted data: [%s]", sprint_hex(data,len) );
1119         crypto1_destroy(traceCrypto1);
1120         return 0;
1121 }
1122
1123 /** validate_prng_nonce
1124  * Determine if nonce is deterministic. ie: Suspectable to Darkside attack.
1125  * returns
1126  *   true = weak prng
1127  *   false = hardend prng
1128  */
1129 bool validate_prng_nonce(uint32_t nonce) {
1130         uint16_t *dist = 0;
1131         uint16_t x, i;
1132
1133         dist = malloc(2 << 16);
1134         if(!dist)
1135                 return -1;
1136
1137         // init prng table:
1138         for (x = i = 1; i; ++i) {
1139                 dist[(x & 0xff) << 8 | x >> 8] = i;
1140                 x = x >> 1 | (x ^ x >> 2 ^ x >> 3 ^ x >> 5) << 15;
1141         }
1142
1143         uint32_t res = (65535 - dist[nonce >> 16] + dist[nonce & 0xffff]) % 65535;
1144
1145         free(dist);
1146         return (res == 16);
1147 }
1148
1149 /* Detect Tag Prng,
1150 * function performs a partial AUTH,  where it tries to authenticate against block0, key A, but only collects tag nonce.
1151 * the tag nonce is check to see if it has a predictable PRNG.
1152 * @returns
1153 *       TRUE if tag uses WEAK prng (ie Now the NACK bug also needs to be present for Darkside attack)
1154 *   FALSE is tag uses HARDEND prng (ie hardnested attack possible, with known key)
1155 */
1156 int DetectClassicPrng(void){
1157
1158         UsbCommand resp, respA;
1159         uint8_t cmd[] = {0x60, 0x00}; // MIFARE_AUTH_KEYA
1160         uint32_t flags = ISO14A_CONNECT | ISO14A_RAW | ISO14A_APPEND_CRC | ISO14A_NO_RATS;
1161
1162         UsbCommand c = {CMD_READER_ISO_14443a, {flags, sizeof(cmd), 0}};
1163         memcpy(c.d.asBytes, cmd, sizeof(cmd));
1164
1165         clearCommandBuffer();
1166         SendCommand(&c);
1167         if (!WaitForResponseTimeout(CMD_ACK, &resp, 2000)) {
1168         PrintAndLog("PRNG UID: Reply timeout.");
1169                 return -1;
1170         }
1171
1172         // if select tag failed.
1173         if (resp.arg[0] == 0) {
1174                 PrintAndLog("PRNG error: selecting tag failed, can't detect prng.");
1175                 return -1;
1176         }
1177
1178         if (!WaitForResponseTimeout(CMD_ACK, &respA, 5000)) {
1179         PrintAndLog("PRNG data: Reply timeout.");
1180                 return -1;
1181         }
1182
1183         // check respA
1184         if (respA.arg[0] != 4) {
1185                 PrintAndLog("PRNG data error: Wrong length: %d", respA.arg[0]);
1186                 return -1;
1187         }
1188
1189         uint32_t nonce = bytes_to_num(respA.d.asBytes, respA.arg[0]);
1190         return validate_prng_nonce(nonce);
1191 }