#include "usb_cmd.h"\r
#include "cmdmain.h"\r
#include "ui.h"\r
+#include "parity.h"\r
#include "util.h"\r
#include "iso14443crc.h"\r
\r
\r
\r
// Darkside attack (hf mf mifare)\r
-static uint32_t nonce2key(uint32_t uid, uint32_t nt, uint32_t nr, uint64_t par_info, uint64_t ks_info, uint64_t **keys) {\r
+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) {\r
struct Crypto1State *states;\r
- uint32_t i, pos, rr; //nr_diff;\r
+ uint32_t i, pos;\r
uint8_t bt, ks3x[8], par[8][8];\r
uint64_t key_recovered;\r
- static uint64_t *keylist;\r
- rr = 0;\r
+ uint64_t *keylist;\r
\r
// Reset the last three significant bits of the reader nonce\r
nr &= 0xffffff1f;\r
}\r
}\r
\r
- states = lfsr_common_prefix(nr, rr, ks3x, par, (par_info == 0));\r
+ states = lfsr_common_prefix(nr, ar, ks3x, par, (par_info == 0));\r
\r
if (states == NULL) {\r
*keys = NULL;\r
int mfDarkside(uint64_t *key)\r
{\r
uint32_t uid = 0;\r
- uint32_t nt = 0, nr = 0;\r
+ uint32_t nt = 0, nr = 0, ar = 0;\r
uint64_t par_list = 0, ks_list = 0;\r
uint64_t *keylist = NULL, *last_keylist = NULL;\r
uint32_t keycount = 0;\r
nt = (uint32_t)bytes_to_num(resp.d.asBytes + 4, 4);\r
par_list = bytes_to_num(resp.d.asBytes + 8, 8);\r
ks_list = bytes_to_num(resp.d.asBytes + 16, 8);\r
- nr = bytes_to_num(resp.d.asBytes + 24, 4);\r
+ nr = (uint32_t)bytes_to_num(resp.d.asBytes + 24, 4);\r
+ ar = (uint32_t)bytes_to_num(resp.d.asBytes + 28, 4);\r
break;\r
}\r
}\r
\r
if (par_list == 0 && c.arg[0] == true) {\r
PrintAndLog("Parity is all zero. Most likely this card sends NACK on every failed authentication.");\r
- PrintAndLog("Attack will take a few seconds longer because we need two consecutive successful runs.");\r
}\r
c.arg[0] = false;\r
\r
- keycount = nonce2key(uid, nt, nr, par_list, ks_list, &keylist);\r
+ keycount = nonce2key(uid, nt, nr, ar, par_list, ks_list, &keylist);\r
\r
if (keycount == 0) {\r
PrintAndLog("Key not found (lfsr_common_prefix list is null). Nt=%08x", nt);\r
continue;\r
}\r
\r
- qsort(keylist, keycount, sizeof(*keylist), compare_uint64);\r
- keycount = intersection(last_keylist, keylist);\r
- if (keycount == 0) {\r
- free(last_keylist);\r
- last_keylist = keylist;\r
- continue;\r
+ if (par_list == 0) {\r
+ qsort(keylist, keycount, sizeof(*keylist), compare_uint64);\r
+ keycount = intersection(last_keylist, keylist);\r
+ if (keycount == 0) {\r
+ free(last_keylist);\r
+ last_keylist = keylist;\r
+ continue;\r
+ }\r
}\r
\r
if (keycount > 1) {\r
for (int i = 0; i < keycount; i += max_keys) {\r
int size = keycount - i > max_keys ? max_keys : keycount - i;\r
for (int j = 0; j < size; j++) {\r
- if (last_keylist == NULL) {\r
- num_to_bytes(keylist[i*max_keys + j], 6, keyBlock);\r
+ if (par_list == 0) {\r
+ num_to_bytes(last_keylist[i*max_keys + j], 6, keyBlock+(j*6));\r
} else {\r
- num_to_bytes(last_keylist[i*max_keys + j], 6, keyBlock);\r
+ num_to_bytes(keylist[i*max_keys + j], 6, keyBlock+(j*6));\r
}\r
}\r
if (!mfCheckKeys(0, 0, false, size, keyBlock, key)) {\r
\r
*key = -1;\r
\r
- UsbCommand c = {CMD_MIFARE_CHKKEYS, {((blockNo & 0xff) | ((keyType&0xff)<<8)), clear_trace, keycnt}};\r
+ UsbCommand c = {CMD_MIFARE_CHKKEYS, {((blockNo & 0xff) | ((keyType & 0xff) << 8)), clear_trace, keycnt}}; \r
memcpy(c.d.asBytes, keyBlock, 6 * keycnt);\r
SendCommand(&c);\r
\r
UsbCommand resp;\r
- if (!WaitForResponseTimeout(CMD_ACK,&resp,3000)) return 1;\r
+ if (!WaitForResponseTimeout(CMD_ACK,&resp,3000)) return 1; \r
if ((resp.arg[0] & 0xff) != 0x01) return 2;\r
*key = bytes_to_num(resp.d.asBytes, 6);\r
return 0;\r
}\r
\r
+int mfCheckKeysSec(uint8_t sectorCnt, uint8_t keyType, uint8_t timeout14a, bool clear_trace, uint8_t keycnt, uint8_t * keyBlock, sector_t * e_sector){\r
+\r
+ uint8_t keyPtr = 0;\r
+\r
+ if (e_sector == NULL)\r
+ return -1;\r
+\r
+ UsbCommand c = {CMD_MIFARE_CHKKEYS, {((sectorCnt & 0xff) | ((keyType & 0xff) << 8)), (clear_trace | 0x02)|((timeout14a & 0xff) << 8), keycnt}}; \r
+ memcpy(c.d.asBytes, keyBlock, 6 * keycnt);\r
+ SendCommand(&c);\r
+\r
+ UsbCommand resp;\r
+ if (!WaitForResponseTimeoutW(CMD_ACK, &resp, MAX(3000, 1000 + 13 * sectorCnt * keycnt * (keyType == 2 ? 2 : 1)), false)) return 1; // timeout: 13 ms / fail auth\r
+ if ((resp.arg[0] & 0xff) != 0x01) return 2;\r
+ \r
+ bool foundAKey = false;\r
+ for(int sec = 0; sec < sectorCnt; sec++){\r
+ for(int keyAB = 0; keyAB < 2; keyAB++){\r
+ keyPtr = *(resp.d.asBytes + keyAB * 40 + sec);\r
+ if (keyPtr){\r
+ e_sector[sec].foundKey[keyAB] = true;\r
+ e_sector[sec].Key[keyAB] = bytes_to_num(keyBlock + (keyPtr - 1) * 6, 6);\r
+ foundAKey = true;\r
+ }\r
+ }\r
+ }\r
+ return foundAKey ? 0 : 3;\r
+}\r
+\r
// Compare 16 Bits out of cryptostate\r
int Compare16Bits(const void * a, const void * b) {\r
if ((*(uint64_t*)b & 0x00ff000000ff0000) == (*(uint64_t*)a & 0x00ff000000ff0000)) return 0;\r
\r
\r
// wrapper function for multi-threaded lfsr_recovery32\r
-void* nested_worker_thread(void *arg)\r
+void\r
+#ifdef __has_attribute\r
+#if __has_attribute(force_align_arg_pointer)\r
+__attribute__((force_align_arg_pointer)) \r
+#endif\r
+#endif\r
+*nested_worker_thread(void *arg)\r
{\r
struct Crypto1State *p1;\r
StateList_t *statelist = arg;\r
return statelist->head.slhead;\r
}\r
\r
+\r
int mfnested(uint8_t blockNo, uint8_t keyType, uint8_t *key, uint8_t trgBlockNo, uint8_t trgKeyType, uint8_t *resultKey, bool calibrate)\r
{\r
uint16_t i;\r
return 0;\r
}\r
\r
-int mfCIdentify()\r
-{\r
- UsbCommand c = {CMD_READER_ISO_14443a, {ISO14A_CONNECT | ISO14A_NO_DISCONNECT, 0, 0}};\r
+int mfCIdentify() {\r
+ UsbCommand c = {CMD_MIFARE_CIDENT, {0, 0, 0}};\r
SendCommand(&c);\r
-\r
UsbCommand resp;\r
WaitForResponse(CMD_ACK,&resp);\r
\r
- iso14a_card_select_t card;\r
- memcpy(&card, (iso14a_card_select_t *)resp.d.asBytes, sizeof(iso14a_card_select_t));\r
-\r
- uint64_t select_status = resp.arg[0]; // 0: couldn't read, 1: OK, with ATS, 2: OK, no ATS, 3: proprietary Anticollision\r
-\r
- if(select_status != 0) {\r
- uint8_t rats[] = { 0xE0, 0x80 }; // FSDI=8 (FSD=256), CID=0\r
- c.arg[0] = ISO14A_RAW | ISO14A_APPEND_CRC | ISO14A_NO_DISCONNECT;\r
- c.arg[1] = 2;\r
- c.arg[2] = 0;\r
- memcpy(c.d.asBytes, rats, 2);\r
- SendCommand(&c);\r
- WaitForResponse(CMD_ACK,&resp);\r
- }\r
-\r
- c.cmd = CMD_MIFARE_CIDENT;\r
- c.arg[0] = 0;\r
- c.arg[1] = 0;\r
- c.arg[2] = 0;\r
- SendCommand(&c);\r
- WaitForResponse(CMD_ACK,&resp);\r
-\r
uint8_t isGeneration = resp.arg[0] & 0xff;\r
switch( isGeneration ){\r
case 1: PrintAndLog("Chinese magic backdoor commands (GEN 1a) detected"); break;\r
default: PrintAndLog("No chinese magic backdoor command detected"); break;\r
}\r
\r
- // disconnect\r
- c.cmd = CMD_READER_ISO_14443a;\r
- c.arg[0] = 0;\r
- c.arg[1] = 0;\r
- c.arg[2] = 0;\r
- SendCommand(&c);\r
-\r
return (int) isGeneration;\r
}\r
\r
\r
struct Crypto1State *revstate;\r
uint64_t lfsr;\r
+uint64_t ui64Key;\r
uint32_t ks2;\r
uint32_t ks3;\r
\r
-uint32_t uid; // serial number\r
-uint32_t nt; // tag challenge\r
-uint32_t nr_enc; // encrypted reader challenge\r
-uint32_t ar_enc; // encrypted reader response\r
-uint32_t at_enc; // encrypted tag response\r
+uint32_t uid; // serial number\r
+uint32_t nt; // tag challenge\r
+uint32_t nt_enc; // encrypted tag challenge\r
+uint8_t nt_enc_par; // encrypted tag challenge parity\r
+uint32_t nr_enc; // encrypted reader challenge\r
+uint32_t ar_enc; // encrypted reader response\r
+uint8_t ar_enc_par; // encrypted reader response parity\r
+uint32_t at_enc; // encrypted tag response\r
+uint8_t at_enc_par; // encrypted tag response parity\r
\r
int isTraceCardEmpty(void) {\r
return ((traceCard[0] == 0) && (traceCard[1] == 0) && (traceCard[2] == 0) && (traceCard[3] == 0));\r
for (int i = 0; i < 64; i++) { // blocks\r
for (int j = 0; j < 16; j++) // bytes\r
fprintf(f, "%02x", *(traceCard + i * 16 + j));\r
- fprintf(f,"\n");\r
+ if (i < 63)\r
+ fprintf(f,"\n");\r
}\r
fclose(f);\r
return 0;\r
return;\r
}\r
\r
+bool NTParityCheck(uint32_t ntx) {\r
+ if (\r
+ (oddparity8(ntx >> 8 & 0xff) ^ (ntx & 0x01) ^ ((nt_enc_par >> 5) & 0x01) ^ (nt_enc & 0x01)) ||\r
+ (oddparity8(ntx >> 16 & 0xff) ^ (ntx >> 8 & 0x01) ^ ((nt_enc_par >> 6) & 0x01) ^ (nt_enc >> 8 & 0x01)) ||\r
+ (oddparity8(ntx >> 24 & 0xff) ^ (ntx >> 16 & 0x01) ^ ((nt_enc_par >> 7) & 0x01) ^ (nt_enc >> 16 & 0x01))\r
+ )\r
+ return false;\r
+ \r
+ uint32_t ar = prng_successor(ntx, 64);\r
+ if (\r
+ (oddparity8(ar >> 8 & 0xff) ^ (ar & 0x01) ^ ((ar_enc_par >> 5) & 0x01) ^ (ar_enc & 0x01)) ||\r
+ (oddparity8(ar >> 16 & 0xff) ^ (ar >> 8 & 0x01) ^ ((ar_enc_par >> 6) & 0x01) ^ (ar_enc >> 8 & 0x01)) ||\r
+ (oddparity8(ar >> 24 & 0xff) ^ (ar >> 16 & 0x01) ^ ((ar_enc_par >> 7) & 0x01) ^ (ar_enc >> 16 & 0x01))\r
+ )\r
+ return false;\r
+\r
+ uint32_t at = prng_successor(ntx, 96);\r
+ if (\r
+ (oddparity8(ar & 0xff) ^ (at >> 24 & 0x01) ^ ((ar_enc_par >> 4) & 0x01) ^ (at_enc >> 24 & 0x01)) ||\r
+ (oddparity8(at >> 8 & 0xff) ^ (at & 0x01) ^ ((at_enc_par >> 5) & 0x01) ^ (at_enc & 0x01)) ||\r
+ (oddparity8(at >> 16 & 0xff) ^ (at >> 8 & 0x01) ^ ((at_enc_par >> 6) & 0x01) ^ (at_enc >> 8 & 0x01)) ||\r
+ (oddparity8(at >> 24 & 0xff) ^ (at >> 16 & 0x01) ^ ((at_enc_par >> 7) & 0x01) ^ (at_enc >> 16 & 0x01))\r
+ )\r
+ return false;\r
+ \r
+ return true;\r
+}\r
\r
-int mfTraceDecode(uint8_t *data_src, int len, bool wantSaveToEmlFile) {\r
+\r
+int mfTraceDecode(uint8_t *data_src, int len, uint8_t parity, bool wantSaveToEmlFile) {\r
uint8_t data[64];\r
\r
if (traceState == TRACE_ERROR) return 1;\r
memcpy(data, data_src, len);\r
if ((traceCrypto1) && ((traceState == TRACE_IDLE) || (traceState > TRACE_AUTH_OK))) {\r
mf_crypto1_decrypt(traceCrypto1, data, len, 0);\r
- PrintAndLog("dec> %s", sprint_hex(data, len));\r
+ uint8_t parity[16];\r
+ oddparitybuf(data, len, parity);\r
+ PrintAndLog("dec> %s [%s]", sprint_hex(data, len), printBitsPar(parity, len));\r
AddLogHex(logHexFileName, "dec> ", data, len);\r
}\r
\r
case TRACE_AUTH1:\r
if (len == 4) {\r
traceState = TRACE_AUTH2;\r
- nt = bytes_to_num(data, 4);\r
+ if (!traceCrypto1) {\r
+ nt = bytes_to_num(data, 4);\r
+ } else {\r
+ nt_enc = bytes_to_num(data, 4);\r
+ nt_enc_par = parity;\r
+ }\r
return 0;\r
} else {\r
traceState = TRACE_ERROR;\r
\r
nr_enc = bytes_to_num(data, 4);\r
ar_enc = bytes_to_num(data + 4, 4);\r
+ ar_enc_par = parity << 4;\r
return 0;\r
} else {\r
traceState = TRACE_ERROR;\r
traceState = TRACE_IDLE;\r
\r
at_enc = bytes_to_num(data, 4);\r
-\r
- // decode key here)\r
- ks2 = ar_enc ^ prng_successor(nt, 64);\r
- ks3 = at_enc ^ prng_successor(nt, 96);\r
- revstate = lfsr_recovery64(ks2, ks3);\r
- lfsr_rollback_word(revstate, 0, 0);\r
- lfsr_rollback_word(revstate, 0, 0);\r
- lfsr_rollback_word(revstate, nr_enc, 1);\r
- lfsr_rollback_word(revstate, uid ^ nt, 0);\r
-\r
- crypto1_get_lfsr(revstate, &lfsr);\r
- printf("key> %x%x\n", (unsigned int)((lfsr & 0xFFFFFFFF00000000) >> 32), (unsigned int)(lfsr & 0xFFFFFFFF));\r
- AddLogUint64(logHexFileName, "key> ", lfsr);\r
+ at_enc_par = parity;\r
+ if (!traceCrypto1) {\r
+\r
+ // decode key here)\r
+ ks2 = ar_enc ^ prng_successor(nt, 64);\r
+ ks3 = at_enc ^ prng_successor(nt, 96);\r
+ revstate = lfsr_recovery64(ks2, ks3);\r
+ lfsr_rollback_word(revstate, 0, 0);\r
+ lfsr_rollback_word(revstate, 0, 0);\r
+ lfsr_rollback_word(revstate, nr_enc, 1);\r
+ lfsr_rollback_word(revstate, uid ^ nt, 0);\r
+\r
+ crypto1_get_lfsr(revstate, &lfsr);\r
+ crypto1_destroy(revstate);\r
+ ui64Key = lfsr;\r
+ printf("key> probable key:%x%x Prng:%s ks2:%08x ks3:%08x\n", \r
+ (unsigned int)((lfsr & 0xFFFFFFFF00000000) >> 32), (unsigned int)(lfsr & 0xFFFFFFFF), \r
+ validate_prng_nonce(nt) ? "WEAK": "HARDEND",\r
+ ks2,\r
+ ks3);\r
+ AddLogUint64(logHexFileName, "key> ", lfsr);\r
+ } else {\r
+ if (validate_prng_nonce(nt)) {\r
+ struct Crypto1State *pcs;\r
+ pcs = crypto1_create(ui64Key);\r
+ uint32_t nt1 = crypto1_word(pcs, nt_enc ^ uid, 1) ^ nt_enc;\r
+ uint32_t ar = prng_successor(nt1, 64);\r
+ uint32_t at = prng_successor(nt1, 96);\r
+ 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);\r
+ uint32_t nr1 = crypto1_word(pcs, nr_enc, 1) ^ nr_enc;\r
+ uint32_t ar1 = crypto1_word(pcs, 0, 0) ^ ar_enc;\r
+ uint32_t at1 = crypto1_word(pcs, 0, 0) ^ at_enc;\r
+ printf("key> the same key test. nr1: %08x ar1: %08x at1: %08x \n", nr1, ar1, at1);\r
+\r
+ if (NTParityCheck(nt1))\r
+ printf("key> the same key test OK. key=%x%x\n", (unsigned int)((ui64Key & 0xFFFFFFFF00000000) >> 32), (unsigned int)(ui64Key & 0xFFFFFFFF));\r
+ else\r
+ printf("key> the same key test. check nt parity error.\n");\r
+ \r
+ uint32_t ntc = prng_successor(nt, 90);\r
+ uint32_t ntx = 0;\r
+ int ntcnt = 0;\r
+ for (int i = 0; i < 16383; i++) {\r
+ ntc = prng_successor(ntc, 1);\r
+ if (NTParityCheck(ntc)){\r
+ if (!ntcnt)\r
+ ntx = ntc;\r
+ ntcnt++;\r
+ } \r
+ }\r
+ if (ntcnt)\r
+ printf("key> nt candidate=%08x nonce distance=%d candidates count=%d\n", ntx, nonce_distance(nt, ntx), ntcnt);\r
+ else\r
+ printf("key> don't have any nt candidate( \n");\r
+\r
+ nt = ntx;\r
+ ks2 = ar_enc ^ prng_successor(ntx, 64);\r
+ ks3 = at_enc ^ prng_successor(ntx, 96);\r
+\r
+ // decode key\r
+ revstate = lfsr_recovery64(ks2, ks3);\r
+ lfsr_rollback_word(revstate, 0, 0);\r
+ lfsr_rollback_word(revstate, 0, 0);\r
+ lfsr_rollback_word(revstate, nr_enc, 1);\r
+ lfsr_rollback_word(revstate, uid ^ nt, 0);\r
+\r
+ crypto1_get_lfsr(revstate, &lfsr);\r
+ crypto1_destroy(revstate);\r
+ ui64Key = lfsr;\r
+ printf("key> probable key:%x%x ks2:%08x ks3:%08x\n", \r
+ (unsigned int)((lfsr & 0xFFFFFFFF00000000) >> 32), (unsigned int)(lfsr & 0xFFFFFFFF),\r
+ ks2,\r
+ ks3);\r
+ AddLogUint64(logHexFileName, "key> ", lfsr);\r
+ } else { \r
+ printf("key> hardnested not implemented!\n");\r
+ \r
+ crypto1_destroy(traceCrypto1);\r
+\r
+ // not implemented\r
+ traceState = TRACE_ERROR;\r
+ }\r
+ }\r
\r
int blockShift = ((traceCurBlock & 0xFC) + 3) * 16;\r
if (isBlockEmpty((traceCurBlock & 0xFC) + 3)) memcpy(traceCard + blockShift + 6, trailerAccessBytes, 4);\r
\r
// set cryptosystem state\r
traceCrypto1 = lfsr_recovery64(ks2, ks3);\r
-\r
-// nt = crypto1_word(traceCrypto1, nt ^ uid, 1) ^ nt;\r
-\r
- /* traceCrypto1 = crypto1_create(lfsr); // key in lfsr\r
- crypto1_word(traceCrypto1, nt ^ uid, 0);\r
- crypto1_word(traceCrypto1, ar, 1);\r
- crypto1_word(traceCrypto1, 0, 0);\r
- crypto1_word(traceCrypto1, 0, 0);*/\r
-\r
return 0;\r
} else {\r
traceState = TRACE_ERROR;\r
return 0;\r
}\r
\r
+/** validate_prng_nonce\r
+ * Determine if nonce is deterministic. ie: Suspectable to Darkside attack.\r
+ * returns\r
+ * true = weak prng\r
+ * false = hardend prng\r
+ */\r
+bool validate_prng_nonce(uint32_t nonce) {\r
+ uint16_t *dist = 0;\r
+ uint16_t x, i;\r
+\r
+ dist = malloc(2 << 16);\r
+ if(!dist)\r
+ return -1;\r
+\r
+ // init prng table:\r
+ for (x = i = 1; i; ++i) {\r
+ dist[(x & 0xff) << 8 | x >> 8] = i;\r
+ x = x >> 1 | (x ^ x >> 2 ^ x >> 3 ^ x >> 5) << 15;\r
+ }\r
+ \r
+ uint32_t res = (65535 - dist[nonce >> 16] + dist[nonce & 0xffff]) % 65535;\r
+ \r
+ free(dist); \r
+ return (res == 16);\r
+}\r
+\r
+/* Detect Tag Prng, \r
+* function performs a partial AUTH, where it tries to authenticate against block0, key A, but only collects tag nonce.\r
+* the tag nonce is check to see if it has a predictable PRNG.\r
+* @returns \r
+* TRUE if tag uses WEAK prng (ie Now the NACK bug also needs to be present for Darkside attack)\r
+* FALSE is tag uses HARDEND prng (ie hardnested attack possible, with known key)\r
+*/\r
+int DetectClassicPrng(void){\r
+\r
+ UsbCommand resp, respA; \r
+ uint8_t cmd[] = {0x60, 0x00}; // MIFARE_AUTH_KEYA\r
+ uint32_t flags = ISO14A_CONNECT | ISO14A_RAW | ISO14A_APPEND_CRC | ISO14A_NO_RATS;\r
+ \r
+ UsbCommand c = {CMD_READER_ISO_14443a, {flags, sizeof(cmd), 0}};\r
+ memcpy(c.d.asBytes, cmd, sizeof(cmd));\r
+\r
+ clearCommandBuffer();\r
+ SendCommand(&c);\r
+ if (!WaitForResponseTimeout(CMD_ACK, &resp, 2000)) {\r
+ PrintAndLog("PRNG UID: Reply timeout.");\r
+ return -1;\r
+ }\r
+ \r
+ // if select tag failed.\r
+ if (resp.arg[0] == 0) {\r
+ PrintAndLog("PRNG error: selecting tag failed, can't detect prng.");\r
+ return -1;\r
+ }\r
+ \r
+ if (!WaitForResponseTimeout(CMD_ACK, &respA, 5000)) {\r
+ PrintAndLog("PRNG data: Reply timeout.");\r
+ return -1;\r
+ }\r
+\r
+ // check respA\r
+ if (respA.arg[0] != 4) {\r
+ PrintAndLog("PRNG data error: Wrong length: %d", respA.arg[0]);\r
+ return -1;\r
+ }\r
+\r
+ uint32_t nonce = bytes_to_num(respA.d.asBytes, respA.arg[0]);\r
+ return validate_prng_nonce(nonce);\r
+}\r