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 static int mfCheckKeysEx(uint8_t blockNo, uint8_t keyType, uint16_t timeout14a, bool clear_trace, uint32_t keycnt, uint8_t *keys, uint64_t *found_key, bool fixed_nonce) {
 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 can take some time!", keycnt);
 232                 PrintAndLog("Press button to abort.");
 233                 display_progress = true;
 234         }
 235
 236         uint8_t bytes_per_key = fixed_nonce ? 5 : 6;
 237         uint32_t max_keys = keycnt > USB_CMD_DATA_SIZE/bytes_per_key ? USB_CMD_DATA_SIZE/bytes_per_key : keycnt;
 238         *found_key = -1;
 239         bool multisectorCheck = false;
 240
 241         for (int i = 0, ii = 0; i < keycnt; i += max_keys) {
 242
 243                 if ((i + max_keys) >= keycnt) {
 244                         max_keys = keycnt - i;
 245                 }
 246
 247                 bool init = (i == 0);
 248                 bool drop_field = (max_keys == keycnt);
 249                 uint8_t flags = clear_trace | multisectorCheck << 1 | init << 2 | drop_field << 3 | fixed_nonce << 4;
 250
 251                 UsbCommand c = {CMD_MIFARE_CHKKEYS, {((blockNo & 0xff) | ((keyType & 0xff) << 8)), flags | timeout14a << 16, max_keys}};
 252                 memcpy(c.d.asBytes, keys + i * bytes_per_key, max_keys * bytes_per_key);
 253                 SendCommand(&c);
 254
 255                 UsbCommand resp;
 256                 if (!WaitForResponseTimeout(CMD_ACK, &resp, 3000))
 257                         return 1;
 258
 259                 if ((resp.arg[0] & 0xff) != 0x01) {
 260                         if ((int)resp.arg[1] < 0) {   // error or user aborted
 261                                 return (int)resp.arg[1];
 262                         } else {                        // nothing found yet
 263                                 if (display_progress && msclock() >= next_print_time) {
 264                                         float brute_force_per_second = (float)(i - ii) / (float)(msclock() - start_time) * 1000.0;
 265                                         ii = i;
 266                                         start_time = msclock();
 267                                         next_print_time = start_time + 10 * 1000;
 268                                         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);
 269                                 }
 270                         }
 271                 } else {                            // success
 272                         if (fixed_nonce) {
 273                                 *found_key = i + resp.arg[1] - 1;
 274                         } else {
 275                                 *found_key = bytes_to_num(resp.d.asBytes, 6);
 276                         }
 277                         return 0;
 278                 }
 279         }
 280
 281         return 2;   // nothing found
 282 }
 283
 284
 285 int mfCheckKeys(uint8_t blockNo, uint8_t keyType, uint16_t timeout14a, bool clear_trace, uint32_t keycnt, uint8_t *keys, uint64_t *found_key) {
 286         return mfCheckKeysEx(blockNo, keyType, timeout14a, clear_trace, keycnt, keys, found_key, false);
 287 }
 288
 289
 290 static int mfCheckKeysFixedNonce(uint8_t blockNo, uint8_t keyType, uint16_t timeout14a, bool clear_trace, uint32_t keycnt, uint8_t *keys, uint32_t *key_index) {
 291         return mfCheckKeysEx(blockNo, keyType, timeout14a, clear_trace, keycnt, keys, (uint64_t*)key_index, true);
 292 }
 293
 294
 295 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) {
 296
 297         uint8_t keyPtr = 0;
 298
 299         if (e_sector == NULL)
 300                 return -1;
 301
 302         bool multisectorCheck = true;
 303         uint8_t flags = clear_trace | multisectorCheck << 1 | init << 2 | drop_field << 3;
 304
 305         UsbCommand c = {CMD_MIFARE_CHKKEYS, {((sectorCnt & 0xff) | ((keyType & 0xff) << 8)), flags | timeout14a << 16, keycnt}};
 306         memcpy(c.d.asBytes, keyBlock, 6 * keycnt);
 307         SendCommand(&c);
 308
 309         UsbCommand resp;
 310         if (!WaitForResponseTimeoutW(CMD_ACK, &resp, MAX(3000, 1000 + 13 * sectorCnt * keycnt * (keyType == 2 ? 2 : 1)), false)) return 1; // timeout: 13 ms / fail auth
 311         if ((resp.arg[0] & 0xff) != 0x01) return 2;
 312
 313         bool foundAKey = false;
 314         for(int sec = 0; sec < sectorCnt; sec++){
 315                 for(int keyAB = 0; keyAB < 2; keyAB++){
 316                         keyPtr = *(resp.d.asBytes + keyAB * 40 + sec);
 317                         if (keyPtr){
 318                                 e_sector[sec].foundKey[keyAB] = true;
 319                                 e_sector[sec].Key[keyAB] = bytes_to_num(keyBlock + (keyPtr - 1) * 6, 6);
 320                                 foundAKey = true;
 321                         }
 322                 }
 323         }
 324         return foundAKey ? 0 : 3;
 325 }
 326
 327 // Compare 16 Bits out of cryptostate
 328 int Compare16Bits(const void * a, const void * b) {
 329         if ((*(uint64_t*)b & 0x00ff000000ff0000) == (*(uint64_t*)a & 0x00ff000000ff0000)) return 0;
 330         else if ((*(uint64_t*)b & 0x00ff000000ff0000) > (*(uint64_t*)a & 0x00ff000000ff0000)) return 1;
 331         else return -1;
 332 }
 333
 334 typedef
 335         struct {
 336                 union {
 337                         struct Crypto1State *slhead;
 338                         uint64_t *keyhead;
 339                 } head;
 340                 union {
 341                         struct Crypto1State *sltail;
 342                         uint64_t *keytail;
 343                 } tail;
 344                 uint32_t len;
 345                 uint32_t uid;
 346                 uint32_t blockNo;
 347                 uint32_t keyType;
 348                 uint32_t nt;
 349                 uint32_t ks1;
 350         } StateList_t;
 351
 352
 353 // wrapper function for multi-threaded lfsr_recovery32
 354 void
 355 #ifdef __has_attribute
 356 #if __has_attribute(force_align_arg_pointer)
 357 __attribute__((force_align_arg_pointer))
 358 #endif
 359 #endif
 360 *nested_worker_thread(void *arg) {
 361         struct Crypto1State *p1;
 362         StateList_t *statelist = arg;
 363
 364         statelist->head.slhead = lfsr_recovery32(statelist->ks1, statelist->nt ^ statelist->uid);
 365         for (p1 = statelist->head.slhead; *(uint64_t *)p1 != 0; p1++);
 366         statelist->len = p1 - statelist->head.slhead;
 367         statelist->tail.sltail = --p1;
 368         qsort(statelist->head.slhead, statelist->len, sizeof(uint64_t), Compare16Bits);
 369
 370         return statelist->head.slhead;
 371 }
 372
 373
 374 static int nested_fixed_nonce(StateList_t statelist, uint32_t fixed_nt, uint32_t authentication_timeout, uint8_t *resultKey) {
 375         // We have a tag with a fixed nonce (nt) and therefore only one (usually long) list of possible crypto states.
 376         // Instead of testing all those keys on the device with a complete authentication cycle, we do all of the crypto operations here.
 377         uint8_t nr_enc[4] = NESTED_FIXED_NR_ENC;             // we use a fixed {nr}
 378         uint8_t ar[4];
 379         num_to_bytes(prng_successor(fixed_nt, 64), 4, ar);   // ... and ar is fixed too
 380
 381         // create an array of possible {ar} and parity bits
 382         uint32_t num_ar_par = statelist.len;
 383         uint8_t *ar_par = calloc(num_ar_par, 5);
 384         if (ar_par == NULL) {
 385                 free(statelist.head.slhead);
 386                 return -4;
 387         }
 388
 389         for (int i = 0; i < num_ar_par; i++) {
 390                 // roll back to initial state using the nt observed with the nested authentication
 391                 lfsr_rollback_word(statelist.head.slhead + i, statelist.nt ^ statelist.uid, 0);
 392                 // instead feed in the fixed_nt for the first authentication
 393                 struct Crypto1State cs = *(statelist.head.slhead + i);
 394                 crypto1_word(&cs, fixed_nt ^ statelist.uid, 0);
 395                 // determine nr such that the resulting {nr} is constant and feed it into the cypher. Calculate the encrypted parity bits
 396                 uint8_t par_enc = 0;
 397                 for (int j = 0; j < 4; j++) {
 398                         uint8_t nr_byte = crypto1_byte(&cs, nr_enc[j], 1) ^ nr_enc[j];
 399                         par_enc |= (((filter(cs.odd) ^ oddparity8(nr_byte)) & 0x01) << (7-j));
 400                 }
 401                 // calculate the encrypted reader response {ar} and its parity bits
 402                 for (int j = 0; j < 4; j++) {
 403                         ar_par[5*i + j] = crypto1_byte(&cs, 0, 0) ^ ar[j];
 404                         par_enc |= ((filter(cs.odd) ^ oddparity8(ar[j])) & 0x01) << (3-j);
 405                 }
 406                 ar_par[5*i + 4] = par_enc;
 407         }
 408
 409         // test each {ar} response
 410         uint32_t key_index;
 411
 412         int isOK = mfCheckKeysFixedNonce(statelist.blockNo, statelist.keyType, authentication_timeout, true, num_ar_par, ar_par, &key_index);
 413
 414         if (isOK == 0) {     // success, key found
 415                 // key_index contains the index into the cypher state list
 416                 struct Crypto1State *p1 = statelist.head.slhead + key_index;
 417                 uint64_t key64;
 418                 crypto1_get_lfsr(p1, &key64);
 419                 num_to_bytes(key64, 6, resultKey);
 420         }
 421         if (isOK == 1) {     // timeout
 422                 isOK = -1;
 423         }
 424         free(statelist.head.slhead);
 425         free(ar_par);
 426         return isOK;
 427 }
 428
 429
 430 static int nested_standard(StateList_t statelists[2], uint32_t authentication_timeout, uint8_t *resultKey) {
 431
 432         // the first 16 Bits of the crypto states already contain part of our key.
 433         // Create the intersection of the two lists based on these 16 Bits and
 434         // roll back the crypto state for the remaining states
 435         struct Crypto1State *p1, *p2, *p3, *p4;
 436         p1 = p3 = statelists[0].head.slhead;
 437         p2 = p4 = statelists[1].head.slhead;
 438         while (p1 <= statelists[0].tail.sltail && p2 <= statelists[1].tail.sltail) {
 439                 if (Compare16Bits(p1, p2) == 0) {
 440                         struct Crypto1State savestate, *savep = &savestate;
 441                         savestate = *p1;
 442                         while (Compare16Bits(p1, savep) == 0 && p1 <= statelists[0].tail.sltail) {
 443                                 *p3 = *p1;
 444                                 lfsr_rollback_word(p3, statelists[0].nt ^ statelists[0].uid, 0);
 445                                 p3++;
 446                                 p1++;
 447                         }
 448                         savestate = *p2;
 449                         while (Compare16Bits(p2, savep) == 0 && p2 <= statelists[1].tail.sltail) {
 450                                 *p4 = *p2;
 451                                 lfsr_rollback_word(p4, statelists[1].nt ^ statelists[1].uid, 0);
 452                                 p4++;
 453                                 p2++;
 454                         }
 455                 }
 456                 else {
 457                         while (Compare16Bits(p1, p2) == -1) p1++;
 458                         while (Compare16Bits(p1, p2) == 1) p2++;
 459                 }
 460         }
 461         *(uint64_t*)p3 = -1;
 462         *(uint64_t*)p4 = -1;
 463         statelists[0].len = p3 - statelists[0].head.slhead;
 464         statelists[1].len = p4 - statelists[1].head.slhead;
 465         statelists[0].tail.sltail=--p3;
 466         statelists[1].tail.sltail=--p4;
 467
 468         // the statelists now contain possible crypto states initialized with the key. The key we are searching for
 469         // must be in the intersection of both lists. Sort the lists and create the intersection:
 470         qsort(statelists[0].head.keyhead, statelists[0].len, sizeof(uint64_t), compare_uint64);
 471         qsort(statelists[1].head.keyhead, statelists[1].len, sizeof(uint64_t), compare_uint64);
 472         statelists[0].len = intersection(statelists[0].head.keyhead, statelists[1].head.keyhead);
 473
 474         // create an array of the possible keys
 475         uint32_t num_keys = statelists[0].len;
 476         uint8_t *keys = calloc(num_keys, 6);
 477         if (keys == NULL) {
 478                 free(statelists[0].head.slhead);
 479                 free(statelists[1].head.slhead);
 480                 return -4;
 481         }
 482
 483         uint64_t key64 = 0;
 484         for (int i = 0; i < num_keys; i++) {
 485                 crypto1_get_lfsr(statelists[0].head.slhead + i, &key64);
 486                 num_to_bytes(key64, 6, keys + i*6);
 487         }
 488
 489         // and test each key with mfCheckKeys
 490         int isOK = mfCheckKeys(statelists[0].blockNo, statelists[0].keyType, authentication_timeout, true, num_keys, keys, &key64);
 491
 492         if (isOK == 0) {     // success, key found
 493                 num_to_bytes(key64, 6, resultKey);
 494         }
 495         if (isOK == 1) {     // timeout
 496                 isOK = -1;
 497         }
 498         free(statelists[0].head.slhead);
 499         free(statelists[1].head.slhead);
 500         free(keys);
 501         return isOK;
 502 }
 503
 504
 505 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) {
 506
 507         // flush queue
 508         clearCommandBuffer();
 509
 510         UsbCommand c = {CMD_MIFARE_NESTED, {blockNo + keyType * 0x100, trgBlockNo + trgKeyType * 0x100, calibrate}};
 511         memcpy(c.d.asBytes, key, 6);
 512         SendCommand(&c);
 513
 514         UsbCommand resp;
 515         if (!WaitForResponseTimeout(CMD_ACK, &resp, 1500)) {
 516                 return -1;
 517         }
 518
 519         if ((int)resp.arg[0]) {
 520                 return (int)resp.arg[0];  // error during nested
 521         }
 522
 523         uint32_t uid;
 524         memcpy(&uid, resp.d.asBytes, 4);
 525         PrintAndLog("uid:%08x trgbl=%d trgkey=%x", uid, (uint16_t)resp.arg[2] & 0xff, (uint16_t)resp.arg[2] >> 8);
 526
 527         StateList_t statelists[2];
 528         for (int i = 0; i < 2; i++) {
 529                 statelists[i].blockNo = resp.arg[2] & 0xff;
 530                 statelists[i].keyType = (resp.arg[2] >> 8) & 0xff;
 531                 statelists[i].uid = uid;
 532                 memcpy(&statelists[i].nt,  (void *)(resp.d.asBytes + 4 + i * 8 + 0), 4);
 533                 memcpy(&statelists[i].ks1, (void *)(resp.d.asBytes + 4 + i * 8 + 4), 4);
 534         }
 535
 536         uint32_t authentication_timeout;
 537         memcpy(&authentication_timeout, resp.d.asBytes + 20, 4);
 538         PrintAndLog("Setting authentication timeout to %" PRIu32 "us", authentication_timeout * 1000 / 106);
 539
 540         uint8_t num_unique_nonces;
 541         uint32_t fixed_nt = 0;
 542         if (statelists[0].nt == statelists[1].nt && statelists[0].ks1 == statelists[1].ks1) {
 543                 num_unique_nonces = 1;
 544                 memcpy(&fixed_nt, resp.d.asBytes + 24, 4);
 545                 PrintAndLog("Fixed nt detected: %08" PRIx32 " on first authentication, %08" PRIx32 " on nested authentication", fixed_nt, statelists[0].nt);
 546         } else {
 547                 num_unique_nonces = 2;
 548         }
 549
 550         // create and run worker threads to calculate possible crypto states
 551         pthread_t thread_id[2];
 552         for (int i = 0; i < num_unique_nonces; i++) {
 553                 pthread_create(thread_id + i, NULL, nested_worker_thread, &statelists[i]);
 554         }
 555         // wait for threads to terminate:
 556         for (int i = 0; i < num_unique_nonces; i++) {
 557                 pthread_join(thread_id[i], (void*)&statelists[i].head.slhead);
 558         }
 559
 560         if (num_unique_nonces == 2) {
 561                 return nested_standard(statelists, authentication_timeout, resultKey);
 562         } else {
 563                 return nested_fixed_nonce(statelists[0], fixed_nt, authentication_timeout, resultKey);
 564         }
 565 }
 566
 567
 568 // MIFARE
 569 int mfReadSector(uint8_t sectorNo, uint8_t keyType, uint8_t *key, uint8_t *data) {
 570
 571         UsbCommand c = {CMD_MIFARE_READSC, {sectorNo, keyType, 0}};
 572         memcpy(c.d.asBytes, key, 6);
 573         clearCommandBuffer();
 574         SendCommand(&c);
 575
 576         UsbCommand resp;
 577         if (WaitForResponseTimeout(CMD_ACK, &resp, 1500)) {
 578                 uint8_t isOK  = resp.arg[0] & 0xff;
 579
 580                 if (isOK) {
 581                         memcpy(data, resp.d.asBytes, mfNumBlocksPerSector(sectorNo) * 16);
 582                         return 0;
 583                 } else {
 584                         return 1;
 585                 }
 586         } else {
 587                 PrintAndLogEx(ERR, "Command execute timeout");
 588                 return 2;
 589         }
 590
 591         return 0;
 592 }
 593
 594 // EMULATOR
 595
 596 int mfEmlGetMem(uint8_t *data, int blockNum, int blocksCount) {
 597         UsbCommand c = {CMD_MIFARE_EML_MEMGET, {blockNum, blocksCount, 0}};
 598         SendCommand(&c);
 599
 600   UsbCommand resp;
 601         if (!WaitForResponseTimeout(CMD_ACK,&resp,1500)) return 1;
 602         memcpy(data, resp.d.asBytes, blocksCount * 16);
 603         return 0;
 604 }
 605
 606 int mfEmlSetMem(uint8_t *data, int blockNum, int blocksCount) {
 607         UsbCommand c = {CMD_MIFARE_EML_MEMSET, {blockNum, blocksCount, 0}};
 608         memcpy(c.d.asBytes, data, blocksCount * 16);
 609         SendCommand(&c);
 610         return 0;
 611 }
 612
 613 // "MAGIC" CARD
 614
 615 int mfCGetBlock(uint8_t blockNo, uint8_t *data, uint8_t params) {
 616         uint8_t isOK = 0;
 617
 618         UsbCommand c = {CMD_MIFARE_CGETBLOCK, {params, 0, blockNo}};
 619         SendCommand(&c);
 620
 621         UsbCommand resp;
 622         if (WaitForResponseTimeout(CMD_ACK,&resp,1500)) {
 623                 isOK  = resp.arg[0] & 0xff;
 624                 memcpy(data, resp.d.asBytes, 16);
 625                 if (!isOK) return 2;
 626         } else {
 627                 PrintAndLog("Command execute timeout");
 628                 return 1;
 629         }
 630         return 0;
 631 }
 632
 633 int mfCSetBlock(uint8_t blockNo, uint8_t *data, uint8_t *uid, bool wantWipe, uint8_t params) {
 634
 635         uint8_t isOK = 0;
 636         UsbCommand c = {CMD_MIFARE_CSETBLOCK, {wantWipe, params & (0xFE | (uid == NULL ? 0:1)), blockNo}};
 637         memcpy(c.d.asBytes, data, 16);
 638         SendCommand(&c);
 639
 640         UsbCommand resp;
 641         if (WaitForResponseTimeout(CMD_ACK, &resp, 1500)) {
 642                 isOK  = resp.arg[0] & 0xff;
 643                 if (uid != NULL)
 644                         memcpy(uid, resp.d.asBytes, 4);
 645                 if (!isOK)
 646                         return 2;
 647         } else {
 648                 PrintAndLog("Command execute timeout");
 649                 return 1;
 650         }
 651
 652         return 0;
 653 }
 654
 655 int mfCWipe(uint32_t numSectors, bool gen1b, bool wantWipe, bool wantFill) {
 656         uint8_t isOK = 0;
 657         uint8_t cmdParams = wantWipe + wantFill * 0x02 + gen1b * 0x04;
 658         UsbCommand c = {CMD_MIFARE_CWIPE, {numSectors, cmdParams, 0}};
 659         SendCommand(&c);
 660
 661         UsbCommand resp;
 662         WaitForResponse(CMD_ACK,&resp);
 663         isOK  = resp.arg[0] & 0xff;
 664
 665         return isOK;
 666 }
 667
 668 int mfCSetUID(uint8_t *uid, uint8_t *atqa, uint8_t *sak, uint8_t *oldUID) {
 669         uint8_t oldblock0[16] = {0x00};
 670         uint8_t block0[16] = {0x00};
 671         int gen = 0, res;
 672
 673         gen = mfCIdentify();
 674
 675         /* generation 1a magic card by default */
 676         uint8_t cmdParams = CSETBLOCK_SINGLE_OPER;
 677         if (gen == 2) {
 678                 /* generation 1b magic card */
 679                 cmdParams = CSETBLOCK_SINGLE_OPER | CSETBLOCK_MAGIC_1B;
 680         }
 681
 682         res = mfCGetBlock(0, oldblock0, cmdParams);
 683
 684         if (res == 0) {
 685                 memcpy(block0, oldblock0, 16);
 686                 PrintAndLog("old block 0:  %s", sprint_hex(block0,16));
 687         } else {
 688                 PrintAndLog("Couldn't get old data. Will write over the last bytes of Block 0.");
 689         }
 690
 691         // fill in the new values
 692         // UID
 693         memcpy(block0, uid, 4);
 694         // Mifare UID BCC
 695         block0[4] = block0[0] ^ block0[1] ^ block0[2] ^ block0[3];
 696         // mifare classic SAK(byte 5) and ATQA(byte 6 and 7, reversed)
 697         if (sak != NULL)
 698                 block0[5] = sak[0];
 699         if (atqa != NULL) {
 700                 block0[6] = atqa[1];
 701                 block0[7] = atqa[0];
 702         }
 703         PrintAndLog("new block 0:  %s", sprint_hex(block0, 16));
 704
 705         res = mfCSetBlock(0, block0, oldUID, false, cmdParams);
 706         if (res) {
 707                 PrintAndLog("Can't set block 0. Error: %d", res);
 708                 return res;
 709         }
 710
 711         return 0;
 712 }
 713
 714 int mfCIdentify() {
 715         UsbCommand c = {CMD_MIFARE_CIDENT, {0, 0, 0}};
 716         SendCommand(&c);
 717         UsbCommand resp;
 718         WaitForResponse(CMD_ACK,&resp);
 719
 720         uint8_t isGeneration = resp.arg[0] & 0xff;
 721         switch( isGeneration ){
 722                 case 1: PrintAndLog("Chinese magic backdoor commands (GEN 1a) detected"); break;
 723                 case 2: PrintAndLog("Chinese magic backdoor command (GEN 1b) detected"); break;
 724                 default: PrintAndLog("No chinese magic backdoor command detected"); break;
 725         }
 726
 727         return (int) isGeneration;
 728 }
 729
 730
 731 // SNIFFER
 732
 733 // constants
 734 static uint8_t trailerAccessBytes[4] = {0x08, 0x77, 0x8F, 0x00};
 735
 736 // variables
 737 char logHexFileName[FILE_PATH_SIZE] = {0x00};
 738 static uint8_t traceCard[4096] = {0x00};
 739 static char traceFileName[FILE_PATH_SIZE] = {0x00};
 740 static int traceState = TRACE_IDLE;
 741 static uint8_t traceCurBlock = 0;
 742 static uint8_t traceCurKey = 0;
 743
 744 struct Crypto1State *traceCrypto1 = NULL;
 745
 746 struct Crypto1State *revstate;
 747 uint64_t lfsr;
 748 uint64_t ui64Key;
 749 uint32_t ks2;
 750 uint32_t ks3;
 751
 752 uint32_t uid;       // serial number
 753 uint32_t nt;        // tag challenge
 754 uint32_t nt_enc;    // encrypted tag challenge
 755 uint8_t nt_enc_par; // encrypted tag challenge parity
 756 uint32_t nr_enc;    // encrypted reader challenge
 757 uint32_t ar_enc;    // encrypted reader response
 758 uint8_t ar_enc_par; // encrypted reader response parity
 759 uint32_t at_enc;    // encrypted tag response
 760 uint8_t at_enc_par; // encrypted tag response parity
 761
 762 int isTraceCardEmpty(void) {
 763         return ((traceCard[0] == 0) && (traceCard[1] == 0) && (traceCard[2] == 0) && (traceCard[3] == 0));
 764 }
 765
 766 int isBlockEmpty(int blockN) {
 767         for (int i = 0; i < 16; i++)
 768                 if (traceCard[blockN * 16 + i] != 0) return 0;
 769
 770         return 1;
 771 }
 772
 773 int isBlockTrailer(int blockN) {
 774  return ((blockN & 0x03) == 0x03);
 775 }
 776
 777 int saveTraceCard(void) {
 778         FILE * f;
 779
 780         if ((!strlen(traceFileName)) || (isTraceCardEmpty())) return 0;
 781
 782         f = fopen(traceFileName, "w+");
 783         if ( !f ) return 1;
 784
 785         for (int i = 0; i < 64; i++) {  // blocks
 786                 for (int j = 0; j < 16; j++)  // bytes
 787                         fprintf(f, "%02x", *(traceCard + i * 16 + j));
 788                 if (i < 63)
 789                         fprintf(f,"\n");
 790         }
 791         fclose(f);
 792         return 0;
 793 }
 794
 795 int loadTraceCard(uint8_t *tuid) {
 796         FILE * f;
 797         char buf[64] = {0x00};
 798         uint8_t buf8[64] = {0x00};
 799         int i, blockNum;
 800
 801         if (!isTraceCardEmpty())
 802                 saveTraceCard();
 803
 804         memset(traceCard, 0x00, 4096);
 805         memcpy(traceCard, tuid + 3, 4);
 806
 807         FillFileNameByUID(traceFileName, tuid, ".eml", 7);
 808
 809         f = fopen(traceFileName, "r");
 810         if (!f) return 1;
 811
 812         blockNum = 0;
 813
 814         while(!feof(f)){
 815
 816                 memset(buf, 0, sizeof(buf));
 817                 if (fgets(buf, sizeof(buf), f) == NULL) {
 818                         PrintAndLog("File reading error.");
 819                         fclose(f);
 820                         return 2;
 821                 }
 822
 823                 if (strlen(buf) < 32){
 824                         if (feof(f)) break;
 825                         PrintAndLog("File content error. Block data must include 32 HEX symbols");
 826                         fclose(f);
 827                         return 2;
 828                 }
 829                 for (i = 0; i < 32; i += 2)
 830                         sscanf(&buf[i], "%02x", (unsigned int *)&buf8[i / 2]);
 831
 832                 memcpy(traceCard + blockNum * 16, buf8, 16);
 833
 834                 blockNum++;
 835         }
 836         fclose(f);
 837
 838         return 0;
 839 }
 840
 841 int mfTraceInit(uint8_t *tuid, uint8_t *atqa, uint8_t sak, bool wantSaveToEmlFile) {
 842
 843         if (traceCrypto1)
 844                 crypto1_destroy(traceCrypto1);
 845
 846         traceCrypto1 = NULL;
 847
 848         if (wantSaveToEmlFile)
 849                 loadTraceCard(tuid);
 850
 851         traceCard[4] = traceCard[0] ^ traceCard[1] ^ traceCard[2] ^ traceCard[3];
 852         traceCard[5] = sak;
 853         memcpy(&traceCard[6], atqa, 2);
 854         traceCurBlock = 0;
 855         uid = bytes_to_num(tuid + 3, 4);
 856
 857         traceState = TRACE_IDLE;
 858
 859         return 0;
 860 }
 861
 862 void mf_crypto1_decrypt(struct Crypto1State *pcs, uint8_t *data, int len, bool isEncrypted){
 863         uint8_t bt = 0;
 864         int i;
 865
 866         if (len != 1) {
 867                 for (i = 0; i < len; i++)
 868                         data[i] = crypto1_byte(pcs, 0x00, isEncrypted) ^ data[i];
 869         } else {
 870                 bt = 0;
 871                 for (i = 0; i < 4; i++)
 872                         bt |= (crypto1_bit(pcs, 0, isEncrypted) ^ BIT(data[0], i)) << i;
 873
 874                 data[0] = bt;
 875         }
 876         return;
 877 }
 878
 879 bool NTParityCheck(uint32_t ntx) {
 880         if (
 881                 (oddparity8(ntx >> 8 & 0xff) ^ (ntx & 0x01) ^ ((nt_enc_par >> 5) & 0x01) ^ (nt_enc & 0x01)) ||
 882                 (oddparity8(ntx >> 16 & 0xff) ^ (ntx >> 8 & 0x01) ^ ((nt_enc_par >> 6) & 0x01) ^ (nt_enc >> 8 & 0x01)) ||
 883                 (oddparity8(ntx >> 24 & 0xff) ^ (ntx >> 16 & 0x01) ^ ((nt_enc_par >> 7) & 0x01) ^ (nt_enc >> 16 & 0x01))
 884                 )
 885                 return false;
 886
 887         uint32_t ar = prng_successor(ntx, 64);
 888         if (
 889                 (oddparity8(ar >> 8 & 0xff) ^ (ar & 0x01) ^ ((ar_enc_par >> 5) & 0x01) ^ (ar_enc & 0x01)) ||
 890                 (oddparity8(ar >> 16 & 0xff) ^ (ar >> 8 & 0x01) ^ ((ar_enc_par >> 6) & 0x01) ^ (ar_enc >> 8 & 0x01)) ||
 891                 (oddparity8(ar >> 24 & 0xff) ^ (ar >> 16 & 0x01) ^ ((ar_enc_par >> 7) & 0x01) ^ (ar_enc >> 16 & 0x01))
 892                 )
 893                 return false;
 894
 895         uint32_t at = prng_successor(ntx, 96);
 896         if (
 897                 (oddparity8(ar & 0xff) ^ (at >> 24 & 0x01) ^ ((ar_enc_par >> 4) & 0x01) ^ (at_enc >> 24 & 0x01)) ||
 898                 (oddparity8(at >> 8 & 0xff) ^ (at & 0x01) ^ ((at_enc_par >> 5) & 0x01) ^ (at_enc & 0x01)) ||
 899                 (oddparity8(at >> 16 & 0xff) ^ (at >> 8 & 0x01) ^ ((at_enc_par >> 6) & 0x01) ^ (at_enc >> 8 & 0x01)) ||
 900                 (oddparity8(at >> 24 & 0xff) ^ (at >> 16 & 0x01) ^ ((at_enc_par >> 7) & 0x01) ^ (at_enc >> 16 & 0x01))
 901                 )
 902                 return false;
 903
 904         return true;
 905 }
 906
 907
 908 int mfTraceDecode(uint8_t *data_src, int len, uint8_t parity, bool wantSaveToEmlFile) {
 909         uint8_t data[64];
 910
 911         if (traceState == TRACE_ERROR) return 1;
 912         if (len > 64) {
 913                 traceState = TRACE_ERROR;
 914                 return 1;
 915         }
 916
 917         memcpy(data, data_src, len);
 918         if ((traceCrypto1) && ((traceState == TRACE_IDLE) || (traceState > TRACE_AUTH_OK))) {
 919                 mf_crypto1_decrypt(traceCrypto1, data, len, 0);
 920                 uint8_t parity[16];
 921                 oddparitybuf(data, len, parity);
 922                 PrintAndLog("dec> %s [%s]", sprint_hex(data, len), printBitsPar(parity, len));
 923                 AddLogHex(logHexFileName, "dec> ", data, len);
 924         }
 925
 926         switch (traceState) {
 927         case TRACE_IDLE:
 928                 // check packet crc16!
 929                 if ((len >= 4) && (!CheckCrc14443(CRC_14443_A, data, len))) {
 930                         PrintAndLog("dec> CRC ERROR!!!");
 931                         AddLogLine(logHexFileName, "dec> ", "CRC ERROR!!!");
 932                         traceState = TRACE_ERROR;  // do not decrypt the next commands
 933                         return 1;
 934                 }
 935
 936                 // AUTHENTICATION
 937                 if ((len ==4) && ((data[0] == 0x60) || (data[0] == 0x61))) {
 938                         traceState = TRACE_AUTH1;
 939                         traceCurBlock = data[1];
 940                         traceCurKey = data[0] == 60 ? 1:0;
 941                         return 0;
 942                 }
 943
 944                 // READ
 945                 if ((len ==4) && ((data[0] == 0x30))) {
 946                         traceState = TRACE_READ_DATA;
 947                         traceCurBlock = data[1];
 948                         return 0;
 949                 }
 950
 951                 // WRITE
 952                 if ((len ==4) && ((data[0] == 0xA0))) {
 953                         traceState = TRACE_WRITE_OK;
 954                         traceCurBlock = data[1];
 955                         return 0;
 956                 }
 957
 958                 // HALT
 959                 if ((len ==4) && ((data[0] == 0x50) && (data[1] == 0x00))) {
 960                         traceState = TRACE_ERROR;  // do not decrypt the next commands
 961                         return 0;
 962                 }
 963
 964                 return 0;
 965         break;
 966
 967         case TRACE_READ_DATA:
 968                 if (len == 18) {
 969                         traceState = TRACE_IDLE;
 970
 971                         if (isBlockTrailer(traceCurBlock)) {
 972                                 memcpy(traceCard + traceCurBlock * 16 + 6, data + 6, 4);
 973                         } else {
 974                                 memcpy(traceCard + traceCurBlock * 16, data, 16);
 975                         }
 976                         if (wantSaveToEmlFile) saveTraceCard();
 977                         return 0;
 978                 } else {
 979                         traceState = TRACE_ERROR;
 980                         return 1;
 981                 }
 982         break;
 983
 984         case TRACE_WRITE_OK:
 985                 if ((len == 1) && (data[0] == 0x0a)) {
 986                         traceState = TRACE_WRITE_DATA;
 987
 988                         return 0;
 989                 } else {
 990                         traceState = TRACE_ERROR;
 991                         return 1;
 992                 }
 993         break;
 994
 995         case TRACE_WRITE_DATA:
 996                 if (len == 18) {
 997                         traceState = TRACE_IDLE;
 998
 999                         memcpy(traceCard + traceCurBlock * 16, data, 16);
1000                         if (wantSaveToEmlFile) saveTraceCard();
1001                         return 0;
1002                 } else {
1003                         traceState = TRACE_ERROR;
1004                         return 1;
1005                 }
1006         break;
1007
1008         case TRACE_AUTH1:
1009                 if (len == 4) {
1010                         traceState = TRACE_AUTH2;
1011                         if (!traceCrypto1) {
1012                                 nt = bytes_to_num(data, 4);
1013                         } else {
1014                                 nt_enc = bytes_to_num(data, 4);
1015                                 nt_enc_par = parity;
1016                         }
1017                         return 0;
1018                 } else {
1019                         traceState = TRACE_ERROR;
1020                         return 1;
1021                 }
1022         break;
1023
1024         case TRACE_AUTH2:
1025                 if (len == 8) {
1026                         traceState = TRACE_AUTH_OK;
1027
1028                         nr_enc = bytes_to_num(data, 4);
1029                         ar_enc = bytes_to_num(data + 4, 4);
1030                         ar_enc_par = parity << 4;
1031                         return 0;
1032                 } else {
1033                         traceState = TRACE_ERROR;
1034                         return 1;
1035                 }
1036         break;
1037
1038         case TRACE_AUTH_OK:
1039                 if (len ==4) {
1040                         traceState = TRACE_IDLE;
1041
1042                         at_enc = bytes_to_num(data, 4);
1043                         at_enc_par = parity;
1044                         if (!traceCrypto1) {
1045
1046                                 //  decode key here)
1047                                 ks2 = ar_enc ^ prng_successor(nt, 64);
1048                                 ks3 = at_enc ^ prng_successor(nt, 96);
1049                                 revstate = lfsr_recovery64(ks2, ks3);
1050                                 lfsr_rollback_word(revstate, 0, 0);
1051                                 lfsr_rollback_word(revstate, 0, 0);
1052                                 lfsr_rollback_word(revstate, nr_enc, 1);
1053                                 lfsr_rollback_word(revstate, uid ^ nt, 0);
1054
1055                                 crypto1_get_lfsr(revstate, &lfsr);
1056                                 crypto1_destroy(revstate);
1057                                 ui64Key = lfsr;
1058                                 printf("key> probable key:%x%x Prng:%s ks2:%08x ks3:%08x\n",
1059                                         (unsigned int)((lfsr & 0xFFFFFFFF00000000) >> 32), (unsigned int)(lfsr & 0xFFFFFFFF),
1060                                         validate_prng_nonce(nt) ? "WEAK": "HARDEND",
1061                                         ks2,
1062                                         ks3);
1063                                 AddLogUint64(logHexFileName, "key> ", lfsr);
1064                         } else {
1065                                 if (validate_prng_nonce(nt)) {
1066                                         struct Crypto1State *pcs;
1067                                         pcs = crypto1_create(ui64Key);
1068                                         uint32_t nt1 = crypto1_word(pcs, nt_enc ^ uid, 1) ^ nt_enc;
1069                                         uint32_t ar = prng_successor(nt1, 64);
1070                                         uint32_t at = prng_successor(nt1, 96);
1071                                         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);
1072                                         uint32_t nr1 = crypto1_word(pcs, nr_enc, 1) ^ nr_enc;
1073                                         uint32_t ar1 = crypto1_word(pcs, 0, 0) ^ ar_enc;
1074                                         uint32_t at1 = crypto1_word(pcs, 0, 0) ^ at_enc;
1075                                         crypto1_destroy(pcs);
1076                                         printf("key> the same key test. nr1: %08x ar1: %08x at1: %08x \n", nr1, ar1, at1);
1077
1078                                         if (NTParityCheck(nt1))
1079                                                 printf("key> the same key test OK. key=%x%x\n", (unsigned int)((ui64Key & 0xFFFFFFFF00000000) >> 32), (unsigned int)(ui64Key & 0xFFFFFFFF));
1080                                         else
1081                                                 printf("key> the same key test. check nt parity error.\n");
1082
1083                                         uint32_t ntc = prng_successor(nt, 90);
1084                                         uint32_t ntx = 0;
1085                                         int ntcnt = 0;
1086                                         for (int i = 0; i < 16383; i++) {
1087                                                 ntc = prng_successor(ntc, 1);
1088                                                 if (NTParityCheck(ntc)){
1089                                                         if (!ntcnt)
1090                                                                 ntx = ntc;
1091                                                         ntcnt++;
1092                                                 }
1093                                         }
1094                                         if (ntcnt)
1095                                                 printf("key> nt candidate=%08x nonce distance=%d candidates count=%d\n", ntx, nonce_distance(nt, ntx), ntcnt);
1096                                         else
1097                                                 printf("key> don't have any nt candidate( \n");
1098
1099                                         nt = ntx;
1100                                         ks2 = ar_enc ^ prng_successor(ntx, 64);
1101                                         ks3 = at_enc ^ prng_successor(ntx, 96);
1102
1103                                         // decode key
1104                                         revstate = lfsr_recovery64(ks2, ks3);
1105                                         lfsr_rollback_word(revstate, 0, 0);
1106                                         lfsr_rollback_word(revstate, 0, 0);
1107                                         lfsr_rollback_word(revstate, nr_enc, 1);
1108                                         lfsr_rollback_word(revstate, uid ^ nt, 0);
1109
1110                                         crypto1_get_lfsr(revstate, &lfsr);
1111                                         crypto1_destroy(revstate);
1112                                         ui64Key = lfsr;
1113                                         printf("key> probable key:%x%x  ks2:%08x ks3:%08x\n",
1114                                                 (unsigned int)((lfsr & 0xFFFFFFFF00000000) >> 32), (unsigned int)(lfsr & 0xFFFFFFFF),
1115                                                 ks2,
1116                                                 ks3);
1117                                         AddLogUint64(logHexFileName, "key> ", lfsr);
1118                                 } else {
1119                                         printf("key> hardnested not implemented!\n");
1120
1121                                         crypto1_destroy(traceCrypto1);
1122
1123                                         // not implemented
1124                                         traceState = TRACE_ERROR;
1125                                 }
1126                         }
1127
1128                         int blockShift = ((traceCurBlock & 0xFC) + 3) * 16;
1129                         if (isBlockEmpty((traceCurBlock & 0xFC) + 3)) memcpy(traceCard + blockShift + 6, trailerAccessBytes, 4);
1130
1131                         if (traceCurKey) {
1132                                 num_to_bytes(lfsr, 6, traceCard + blockShift + 10);
1133                         } else {
1134                                 num_to_bytes(lfsr, 6, traceCard + blockShift);
1135                         }
1136                         if (wantSaveToEmlFile) saveTraceCard();
1137
1138                         if (traceCrypto1) {
1139                                 crypto1_destroy(traceCrypto1);
1140                         }
1141
1142                         // set cryptosystem state
1143                         traceCrypto1 = lfsr_recovery64(ks2, ks3);
1144                         return 0;
1145                 } else {
1146                         traceState = TRACE_ERROR;
1147                         return 1;
1148                 }
1149         break;
1150
1151         default:
1152                 traceState = TRACE_ERROR;
1153                 return 1;
1154         }
1155
1156         return 0;
1157 }
1158
1159 // DECODING
1160
1161 int tryDecryptWord(uint32_t nt, uint32_t ar_enc, uint32_t at_enc, uint8_t *data, int len){
1162         /*
1163         uint32_t nt;      // tag challenge
1164         uint32_t ar_enc;  // encrypted reader response
1165         uint32_t at_enc;  // encrypted tag response
1166         */
1167         if (traceCrypto1) {
1168                 crypto1_destroy(traceCrypto1);
1169         }
1170         ks2 = ar_enc ^ prng_successor(nt, 64);
1171         ks3 = at_enc ^ prng_successor(nt, 96);
1172         traceCrypto1 = lfsr_recovery64(ks2, ks3);
1173
1174         mf_crypto1_decrypt(traceCrypto1, data, len, 0);
1175
1176         PrintAndLog("Decrypted data: [%s]", sprint_hex(data,len) );
1177         crypto1_destroy(traceCrypto1);
1178         return 0;
1179 }
1180
1181 /** validate_prng_nonce
1182  * Determine if nonce is deterministic. ie: Suspectable to Darkside attack.
1183  * returns
1184  *   true = weak prng
1185  *   false = hardend prng
1186  */
1187 bool validate_prng_nonce(uint32_t nonce) {
1188         uint16_t *dist = 0;
1189         uint16_t x, i;
1190
1191         dist = malloc(2 << 16);
1192         if(!dist)
1193                 return -1;
1194
1195         // init prng table:
1196         for (x = i = 1; i; ++i) {
1197                 dist[(x & 0xff) << 8 | x >> 8] = i;
1198                 x = x >> 1 | (x ^ x >> 2 ^ x >> 3 ^ x >> 5) << 15;
1199         }
1200
1201         uint32_t res = (65535 - dist[nonce >> 16] + dist[nonce & 0xffff]) % 65535;
1202
1203         free(dist);
1204         return (res == 16);
1205 }
1206
1207 /* Detect Tag Prng,
1208 * function performs a partial AUTH,  where it tries to authenticate against block0, key A, but only collects tag nonce.
1209 * the tag nonce is check to see if it has a predictable PRNG.
1210 * @returns
1211 *   TRUE if tag uses WEAK prng (ie Now the NACK bug also needs to be present for Darkside attack)
1212 *   FALSE is tag uses HARDEND prng (ie hardnested attack possible, with known key)
1213 */
1214 int DetectClassicPrng(void){
1215
1216         UsbCommand resp, respA;
1217         uint8_t cmd[] = {0x60, 0x00}; // MIFARE_AUTH_KEYA
1218         uint32_t flags = ISO14A_CONNECT | ISO14A_RAW | ISO14A_APPEND_CRC | ISO14A_NO_RATS;
1219
1220         UsbCommand c = {CMD_READER_ISO_14443a, {flags, sizeof(cmd), 0}};
1221         memcpy(c.d.asBytes, cmd, sizeof(cmd));
1222
1223         clearCommandBuffer();
1224         SendCommand(&c);
1225         if (!WaitForResponseTimeout(CMD_NACK, &resp, 2000)) {
1226                 PrintAndLog("PRNG UID: Reply timeout.");
1227                 return -1;
1228         }
1229
1230         // if select tag failed.
1231         if (resp.arg[0] == 0) {
1232                 PrintAndLog("PRNG error: selecting tag failed, can't detect prng.");
1233                 return -1;
1234         }
1235
1236         if (!WaitForResponseTimeout(CMD_ACK, &respA, 5000)) {
1237                 PrintAndLog("PRNG data: Reply timeout.");
1238                 return -1;
1239         }
1240
1241         // check respA
1242         if (respA.arg[0] != 4) {
1243                 PrintAndLog("PRNG data error: Wrong length: %d", respA.arg[0]);
1244                 return -1;
1245         }
1246
1247         uint32_t nonce = bytes_to_num(respA.d.asBytes, respA.arg[0]);
1248         return validate_prng_nonce(nonce);
1249 }