int tryDecryptWord(uint32_t nt, uint32_t ar_enc, uint32_t at_enc, uint8_t *data, int len){
/*
uint32_t nt; // tag challenge
uint32_t nr_enc; // encrypted reader challenge
uint32_t ar_enc; // encrypted reader response
uint32_t at_enc; // encrypted tag response
*/
struct Crypto1State *pcs = NULL;
ks2 = ar_enc ^ prng_successor(nt, 64);
ks3 = at_enc ^ prng_successor(nt, 96);
PrintAndLog("Decrypting data with:");
PrintAndLog(" nt: %08x",nt);
PrintAndLog(" ar_enc: %08x",ar_enc);
PrintAndLog(" at_enc: %08x",at_enc);
PrintAndLog("\nEncrypted data: [%s]", sprint_hex(data,len) );
pcs = lfsr_recovery64(ks2, ks3);
mf_crypto1_decrypt(pcs, data, len, FALSE);
PrintAndLog("Decrypted data: [%s]", sprint_hex(data,len) );
crypto1_destroy(pcs);
return 0;
}
int mfTraceInit(uint8_t *tuid, uint8_t *atqa, uint8_t sak, bool wantSaveToEmlFile) {
if (traceCrypto1)
crypto1_destroy(traceCrypto1);
traceCrypto1 = NULL;
if (wantSaveToEmlFile)
loadTraceCard(tuid);
traceCard[4] = traceCard[0] ^ traceCard[1] ^ traceCard[2] ^ traceCard[3];
traceCard[5] = sak;
memcpy(&traceCard[6], atqa, 2);
traceCurBlock = 0;
uid = bytes_to_num(tuid + 3, 4);
traceState = TRACE_IDLE;
return 0;
}
int mifare_classic_authex(struct Crypto1State *pcs, uint32_t uid, uint8_t blockNo, uint8_t keyType, uint64_t ui64Key, uint8_t isNested, uint32_t *ntptr, uint32_t *timing)
{
// variables
int len;
uint32_t pos;
uint8_t tmp4[4];
uint8_t par[1] = {0};
byte_t nr[4];
uint32_t nt, ntpp; // Supplied tag nonce
uint8_t mf_nr_ar[] = { 0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00 };
uint8_t *receivedAnswer = get_bigbufptr_recvrespbuf();
uint8_t *receivedAnswerPar = receivedAnswer + MAX_FRAME_SIZE;
// Transmit MIFARE_CLASSIC_AUTH
len = mifare_sendcmd_short(pcs, isNested, 0x60 + (keyType & 0x01), blockNo, receivedAnswer, receivedAnswerPar, timing);
if (MF_DBGLEVEL >= 4) Dbprintf("rand tag nonce len: %x", len);
if (len != 4) return 1;
// "random" reader nonce:
nr[0] = 0x55;
nr[1] = 0x41;
nr[2] = 0x49;
nr[3] = 0x92;
// Save the tag nonce (nt)
nt = bytes_to_num(receivedAnswer, 4);
// ----------------------------- crypto1 create
if (isNested)
crypto1_destroy(pcs);
// Init cipher with key
crypto1_create(pcs, ui64Key);
if (isNested == AUTH_NESTED) {
// decrypt nt with help of new key
nt = crypto1_word(pcs, nt ^ uid, 1) ^ nt;
} else {
// Load (plain) uid^nt into the cipher
crypto1_word(pcs, nt ^ uid, 0);
}
// some statistic
if (!ntptr && (MF_DBGLEVEL >= 3))
Dbprintf("auth uid: %08x nt: %08x", uid, nt);
// save Nt
if (ntptr)
*ntptr = nt;
// Generate (encrypted) nr+parity by loading it into the cipher (Nr)
par[0] = 0;
for (pos = 0; pos < 4; pos++)
{
mf_nr_ar[pos] = crypto1_byte(pcs, nr[pos], 0) ^ nr[pos];
par[0] |= (((filter(pcs->odd) ^ oddparity(nr[pos])) & 0x01) << (7-pos));
}
// Skip 32 bits in pseudo random generator
nt = prng_successor(nt,32);
// ar+parity
for (pos = 4; pos < 8; pos++)
{
nt = prng_successor(nt,8);
mf_nr_ar[pos] = crypto1_byte(pcs,0x00,0) ^ (nt & 0xff);
par[0] |= (((filter(pcs->odd) ^ oddparity(nt & 0xff)) & 0x01) << (7-pos));
}
// Transmit reader nonce and reader answer
ReaderTransmitPar(mf_nr_ar, sizeof(mf_nr_ar), par, NULL);
// Receive 4 byte tag answer
len = ReaderReceive(receivedAnswer, receivedAnswerPar);
if (!len)
{
if (MF_DBGLEVEL >= 1) Dbprintf("Authentication failed. Card timeout.");
return 2;
}
memcpy(tmp4, receivedAnswer, 4);
ntpp = prng_successor(nt, 32) ^ crypto1_word(pcs, 0,0);
if (ntpp != bytes_to_num(tmp4, 4)) {
if (MF_DBGLEVEL >= 1) Dbprintf("Authentication failed. Error card response.");
return 3;
}
return 0;
}
int mfTraceDecode(uint8_t *data_src, int len, bool wantSaveToEmlFile) {
uint8_t data[64];
if (traceState == TRACE_ERROR) return 1;
if (len > 64) {
traceState = TRACE_ERROR;
return 1;
}
memcpy(data, data_src, len);
if ((traceCrypto1) && ((traceState == TRACE_IDLE) || (traceState > TRACE_AUTH_OK))) {
mf_crypto1_decrypt(traceCrypto1, data, len, 0);
PrintAndLog("dec> %s", sprint_hex(data, len));
AddLogHex(logHexFileName, "dec> ", data, len);
}
switch (traceState) {
case TRACE_IDLE:
// check packet crc16!
if ((len >= 4) && (!CheckCrc14443(CRC_14443_A, data, len))) {
PrintAndLog("dec> CRC ERROR!!!");
AddLogLine(logHexFileName, "dec> ", "CRC ERROR!!!");
traceState = TRACE_ERROR; // do not decrypt the next commands
return 1;
}
// AUTHENTICATION
if ((len == 4) && ((data[0] == 0x60) || (data[0] == 0x61))) {
traceState = TRACE_AUTH1;
traceCurBlock = data[1];
traceCurKey = data[0] == 60 ? 1:0;
return 0;
}
// READ
if ((len ==4) && ((data[0] == 0x30))) {
traceState = TRACE_READ_DATA;
traceCurBlock = data[1];
return 0;
}
// WRITE
if ((len ==4) && ((data[0] == 0xA0))) {
traceState = TRACE_WRITE_OK;
traceCurBlock = data[1];
return 0;
}
// HALT
if ((len ==4) && ((data[0] == 0x50) && (data[1] == 0x00))) {
traceState = TRACE_ERROR; // do not decrypt the next commands
return 0;
}
return 0;
break;
case TRACE_READ_DATA:
if (len == 18) {
traceState = TRACE_IDLE;
if (isBlockTrailer(traceCurBlock)) {
memcpy(traceCard + traceCurBlock * 16 + 6, data + 6, 4);
} else {
memcpy(traceCard + traceCurBlock * 16, data, 16);
}
if (wantSaveToEmlFile) saveTraceCard();
return 0;
} else {
traceState = TRACE_ERROR;
return 1;
}
break;
case TRACE_WRITE_OK:
if ((len == 1) && (data[0] == 0x0a)) {
traceState = TRACE_WRITE_DATA;
return 0;
} else {
traceState = TRACE_ERROR;
return 1;
}
break;
case TRACE_WRITE_DATA:
if (len == 18) {
traceState = TRACE_IDLE;
memcpy(traceCard + traceCurBlock * 16, data, 16);
if (wantSaveToEmlFile) saveTraceCard();
return 0;
} else {
traceState = TRACE_ERROR;
return 1;
}
break;
case TRACE_AUTH1:
if (len == 4) {
traceState = TRACE_AUTH2;
nt = bytes_to_num(data, 4);
return 0;
} else {
traceState = TRACE_ERROR;
return 1;
}
break;
case TRACE_AUTH2:
if (len == 8) {
traceState = TRACE_AUTH_OK;
nr_enc = bytes_to_num(data, 4);
ar_enc = bytes_to_num(data + 4, 4);
return 0;
} else {
traceState = TRACE_ERROR;
return 1;
}
break;
case TRACE_AUTH_OK:
if (len ==4) {
traceState = TRACE_IDLE;
at_enc = bytes_to_num(data, 4);
// decode key here)
ks2 = ar_enc ^ prng_successor(nt, 64);
ks3 = at_enc ^ prng_successor(nt, 96);
revstate = lfsr_recovery64(ks2, ks3);
lfsr_rollback_word(revstate, 0, 0);
lfsr_rollback_word(revstate, 0, 0);
lfsr_rollback_word(revstate, nr_enc, 1);
lfsr_rollback_word(revstate, uid ^ nt, 0);
crypto1_get_lfsr(revstate, &key);
printf("Key: %012"llx"\n",key);
AddLogUint64(logHexFileName, "key: ", key);
int blockShift = ((traceCurBlock & 0xFC) + 3) * 16;
if (isBlockEmpty((traceCurBlock & 0xFC) + 3)) memcpy(traceCard + blockShift + 6, trailerAccessBytes, 4);
if (traceCurKey) {
num_to_bytes(key, 6, traceCard + blockShift + 10);
} else {
num_to_bytes(key, 6, traceCard + blockShift);
}
if (wantSaveToEmlFile) saveTraceCard();
if (traceCrypto1) {
crypto1_destroy(traceCrypto1);
}
// set cryptosystem state
traceCrypto1 = lfsr_recovery64(ks2, ks3);
// nt = crypto1_word(traceCrypto1, nt ^ uid, 1) ^ nt;
/* traceCrypto1 = crypto1_create(key); // key in lfsr
crypto1_word(traceCrypto1, nt ^ uid, 0);
crypto1_word(traceCrypto1, ar, 1);
crypto1_word(traceCrypto1, 0, 0);
crypto1_word(traceCrypto1, 0, 0);*/
return 0;
} else {
traceState = TRACE_ERROR;
return 1;
}
break;
default:
traceState = TRACE_ERROR;
return 1;
}
return 0;
}
int main (int argc, char *argv[]) {
struct Crypto1State *revstate;
uint64_t key; // recovered key
uint32_t uid; // serial number
uint32_t nt; // tag challenge
uint32_t nr_enc; // encrypted reader challenge
uint32_t ar_enc; // encrypted reader response
uint32_t at_enc; // encrypted tag response
uint32_t ks2; // keystream used to encrypt reader response
uint32_t ks3; // keystream used to encrypt tag response
printf("MIFARE Classic key recovery - based 64 bits of keystream\n");
printf("Recover key from only one complete authentication!\n\n");
if (argc < 6 ) {
printf(" syntax: %s <uid> <nt> <{nr}> <{ar}> <{at}> [enc] [enc...]\n\n", argv[0]);
return 1;
}
int encc = argc - 6;
int enclen[encc];
uint8_t enc[encc][120];
sscanf(argv[1], "%x", &uid);
sscanf(argv[2], "%x", &nt);
sscanf(argv[3], "%x", &nr_enc);
sscanf(argv[4], "%x", &ar_enc);
sscanf(argv[5], "%x", &at_enc);
for (int i = 0; i < encc; i++) {
enclen[i] = strlen(argv[i + 6]) / 2;
for (int i2 = 0; i2 < enclen[i]; i2++) {
sscanf(argv[i+6] + i2*2,"%2x", (uint8_t*)&enc[i][i2]);
}
}
printf("Recovering key for:\n");
printf(" uid: %08x\n", uid);
printf(" nt: %08x\n", nt);
printf(" {nr}: %08x\n", nr_enc);
printf(" {ar}: %08x\n", ar_enc);
printf(" {at}: %08x\n", at_enc);
for (int i = 0; i < encc; i++) {
printf("{enc%d}: ", i);
for (int i2 = 0; i2 < enclen[i]; i2++) {
printf("%02x", enc[i][i2]);
}
printf("\n");
}
/*
uint32_t uid = 0x9c599b32;
uint32_t tag_challenge = 0x82a4166c;
uint32_t nr_enc = 0xa1e458ce;
uint32_t reader_response = 0x6eea41e0;
uint32_t tag_response = 0x5cadf439;
*/
// Generate lfsr succesors of the tag challenge
printf("\nLFSR succesors of the tag challenge:\n");
printf(" nt': %08x\n",prng_successor(nt, 64));
printf(" nt'': %08x\n",prng_successor(nt, 96));
// Extract the keystream from the messages
printf("\nKeystream used to generate {ar} and {at}:\n");
ks2 = ar_enc ^ prng_successor(nt, 64);
ks3 = at_enc ^ prng_successor(nt, 96);
printf(" ks2: %08x\n",ks2);
printf(" ks3: %08x\n",ks3);
revstate = lfsr_recovery64(ks2, ks3);
// Decrypting communication using keystream if presented
if (argc > 6 ) {
printf("\nDecrypted communication:\n");
uint8_t ks4;
int rollb = 0;
for (int i = 0; i < encc; i++) {
printf("{dec%d}: ", i);
for (int i2 = 0; i2 < enclen[i]; i2++) {
ks4 = crypto1_byte(revstate, 0, 0);
printf("%02x", ks4 ^ enc[i][i2]);
rollb += 1;
}
printf("\n");
}
for (int i = 0; i < rollb; i++) {
lfsr_rollback_byte(revstate, 0, 0);
}
}
lfsr_rollback_word(revstate, 0, 0);
lfsr_rollback_word(revstate, 0, 0);
lfsr_rollback_word(revstate, nr_enc, 1);
lfsr_rollback_word(revstate, uid ^ nt, 0);
crypto1_get_lfsr(revstate, &key);
printf("\nFound Key: [%012"llx"]\n\n",key);
crypto1_destroy(revstate);
return 0;
}
