[proxmark3-svn] / client / mifarehost.c

// Merlok, 2011, 2012\r
// people from mifare@nethemba.com, 2010\r
//\r
// This code is licensed to you under the terms of the GNU GPL, version 2 or,\r
// at your option, any later version. See the LICENSE.txt file for the text of\r
// the license.\r
//-----------------------------------------------------------------------------\r
// mifare commands\r
//-----------------------------------------------------------------------------\r
\r
#include <stdio.h>\r
#include <stdlib.h> \r
#include <string.h>\r
#include <pthread.h>\r
#include "mifarehost.h"\r
#include "proxmark3.h"\r
\r
#define llx PRIx64\r
\r
// MIFARE\r
int compar_int(const void * a, const void * b) {\r
	// didn't work: (the result is truncated to 32 bits)\r
	//return (*(uint64_t*)b - *(uint64_t*)a);\r
\r
	// better:\r
	if (*(uint64_t*)b == *(uint64_t*)a) return 0;\r
	else if (*(uint64_t*)b > *(uint64_t*)a) return 1;\r
	else return -1;\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
	else if ((*(uint64_t*)b & 0x00ff000000ff0000) > (*(uint64_t*)a & 0x00ff000000ff0000)) return 1;\r
	else return -1;\r
}\r
\r
typedef \r
	struct {\r
		union {\r
			struct Crypto1State *slhead;\r
			uint64_t *keyhead;\r
		} head;\r
		union {\r
			struct Crypto1State *sltail;\r
			uint64_t *keytail;\r
		} tail;\r
		uint32_t len;\r
		uint32_t uid;\r
		uint32_t blockNo;\r
		uint32_t keyType;\r
		uint32_t nt;\r
		uint32_t ks1;\r
	} StateList_t;\r
\r
\r
// wrapper function for multi-threaded lfsr_recovery32\r
void* nested_worker_thread(void *arg)\r
{\r
	struct Crypto1State *p1;\r
	StateList_t *statelist = arg;\r
\r
	statelist->head.slhead = lfsr_recovery32(statelist->ks1, statelist->nt ^ statelist->uid);\r
	for (p1 = statelist->head.slhead; *(uint64_t *)p1 != 0; p1++);\r
	statelist->len = p1 - statelist->head.slhead;\r
	statelist->tail.sltail = --p1;\r
	qsort(statelist->head.slhead, statelist->len, sizeof(uint64_t), Compare16Bits);\r
	\r
	return statelist->head.slhead;\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
	uint32_t uid;\r
	UsbCommand resp;\r
\r
	StateList_t statelists[2];\r
	struct Crypto1State *p1, *p2, *p3, *p4;\r
	\r
	// flush queue\r
	\r
	UsbCommand c = {CMD_MIFARE_NESTED, {blockNo + keyType * 0x100, trgBlockNo + trgKeyType * 0x100, calibrate}};\r
	memcpy(c.d.asBytes, key, 6);\r
	clearCommandBuffer();\r
	SendCommand(&c);\r
\r
	if (!WaitForResponseTimeout(CMD_ACK, &resp, 1500)) return -1;\r
\r
	// error during nested\r
	if (resp.arg[0]) return resp.arg[0];\r
	\r
	memcpy(&uid, resp.d.asBytes, 4);\r
	PrintAndLog("UID: %08x Block:%d Key: %c", uid, (uint16_t)resp.arg[2] & 0xff, (resp.arg[2] >> 8) ?'A':'B' );\r
			\r
	for (i = 0; i < 2; i++) {\r
		statelists[i].blockNo = resp.arg[2] & 0xff;\r
		statelists[i].keyType = (resp.arg[2] >> 8) & 0xff;\r
		statelists[i].uid = uid;\r
		memcpy(&statelists[i].nt,  (void *)(resp.d.asBytes + 4 + i * 8 + 0), 4);\r
		memcpy(&statelists[i].ks1, (void *)(resp.d.asBytes + 4 + i * 8 + 4), 4);\r
	}\r
	\r
	// calc keys\r
	\r
	pthread_t thread_id[2];\r
		\r
	// create and run worker threads\r
	for (i = 0; i < 2; i++) {\r
		pthread_create(thread_id + i, NULL, nested_worker_thread, &statelists[i]);\r
	}\r
	\r
	// wait for threads to terminate:\r
	for (i = 0; i < 2; i++) {\r
		pthread_join(thread_id[i], (void*)&statelists[i].head.slhead);\r
	}\r
\r
\r
	// the first 16 Bits of the cryptostate already contain part of our key.\r
	// Create the intersection of the two lists based on these 16 Bits and\r
	// roll back the cryptostate\r
	p1 = p3 = statelists[0].head.slhead; \r
	p2 = p4 = statelists[1].head.slhead;\r
	while (p1 <= statelists[0].tail.sltail && p2 <= statelists[1].tail.sltail) {\r
		if (Compare16Bits(p1, p2) == 0) {\r
			struct Crypto1State savestate, *savep = &savestate;\r
			savestate = *p1;\r
			while(Compare16Bits(p1, savep) == 0 && p1 <= statelists[0].tail.sltail) {\r
				*p3 = *p1;\r
				lfsr_rollback_word(p3, statelists[0].nt ^ statelists[0].uid, 0);\r
				p3++;\r
				p1++;\r
			}\r
			savestate = *p2;\r
			while(Compare16Bits(p2, savep) == 0 && p2 <= statelists[1].tail.sltail) {\r
				*p4 = *p2;\r
				lfsr_rollback_word(p4, statelists[1].nt ^ statelists[1].uid, 0);\r
				p4++;\r
				p2++;\r
			}\r
		}\r
		else {\r
			while (Compare16Bits(p1, p2) == -1) p1++;\r
			while (Compare16Bits(p1, p2) == 1) p2++;\r
		}\r
	}\r
	p3->even = 0; p3->odd = 0;\r
	p4->even = 0; p4->odd = 0;\r
	statelists[0].len = p3 - statelists[0].head.slhead;\r
	statelists[1].len = p4 - statelists[1].head.slhead;\r
	statelists[0].tail.sltail=--p3;\r
	statelists[1].tail.sltail=--p4;\r
\r
	// the statelists now contain possible keys. The key we are searching for must be in the\r
	// intersection of both lists. Create the intersection:\r
	qsort(statelists[0].head.keyhead, statelists[0].len, sizeof(uint64_t), compar_int);\r
	qsort(statelists[1].head.keyhead, statelists[1].len, sizeof(uint64_t), compar_int);\r
\r
	uint64_t *p5, *p6, *p7;\r
	p5 = p7 = statelists[0].head.keyhead; \r
	p6 = statelists[1].head.keyhead;\r
	while (p5 <= statelists[0].tail.keytail && p6 <= statelists[1].tail.keytail) {\r
		if (compar_int(p5, p6) == 0) {\r
			*p7++ = *p5++;\r
			p6++;\r
		}\r
		else {\r
			while (compar_int(p5, p6) == -1) p5++;\r
			while (compar_int(p5, p6) == 1) p6++;\r
		}\r
	}\r
	statelists[0].len = p7 - statelists[0].head.keyhead;\r
	statelists[0].tail.keytail=--p7;\r
\r
	memset(resultKey, 0, 6);\r
	// The list may still contain several key candidates. Test each of them with mfCheckKeys\r
	for (i = 0; i < statelists[0].len; i++) {\r
		uint8_t keyBlock[6];\r
		uint64_t key64;\r
		crypto1_get_lfsr(statelists[0].head.slhead + i, &key64);\r
		num_to_bytes(key64, 6, keyBlock);\r
		key64 = 0;\r
		if (!mfCheckKeys(statelists[0].blockNo, statelists[0].keyType, false, 1, keyBlock, &key64)) {\r
			num_to_bytes(key64, 6, resultKey);\r
			break;\r
		}\r
	}\r
	\r
	free(statelists[0].head.slhead);\r
	free(statelists[1].head.slhead);	\r
	return 0;\r
}\r
\r
int mfCheckKeys (uint8_t blockNo, uint8_t keyType, bool clear_trace, uint8_t keycnt, uint8_t * keyBlock, uint64_t * key){\r
\r
	*key = 0;\r
\r
	UsbCommand c = {CMD_MIFARE_CHKKEYS, {((blockNo & 0xff) | ((keyType&0xff)<<8)), clear_trace, keycnt}};\r
	memcpy(c.d.asBytes, keyBlock, 6 * keycnt);\r
	\r
	clearCommandBuffer();\r
	SendCommand(&c);\r
	UsbCommand resp;\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
// EMULATOR\r
\r
int mfEmlGetMem(uint8_t *data, int blockNum, int blocksCount) {\r
	UsbCommand c = {CMD_MIFARE_EML_MEMGET, {blockNum, blocksCount, 0}};\r
	clearCommandBuffer();\r
 	SendCommand(&c);\r
	UsbCommand resp;\r
	if (!WaitForResponseTimeout(CMD_ACK,&resp,1500)) return 1;\r
	memcpy(data, resp.d.asBytes, blocksCount * 16);\r
	return 0;\r
}\r
\r
int mfEmlSetMem(uint8_t *data, int blockNum, int blocksCount) {\r
	return mfEmlSetMem_xt(data, blockNum, blocksCount, 16);\r
}\r
\r
int mfEmlSetMem_xt(uint8_t *data, int blockNum, int blocksCount, int blockBtWidth) {\r
	UsbCommand c = {CMD_MIFARE_EML_MEMSET, {blockNum, blocksCount, blockBtWidth}};\r
	memcpy(c.d.asBytes, data, blocksCount * blockBtWidth); \r
\r
	clearCommandBuffer();\r
	SendCommand(&c);\r
	return 0;\r
}\r
\r
// "MAGIC" CARD\r
\r
int mfCSetUID(uint8_t *uid, uint8_t *atqa, uint8_t *sak, uint8_t *oldUID, uint8_t wipecard) {\r
\r
	uint8_t params = MAGIC_SINGLE;\r
	uint8_t block0[16];\r
	memset(block0, 0x00, sizeof(block0));\r
	\r
\r
	int old = mfCGetBlock(0, block0, params);\r
	if (old == 0) {\r
		PrintAndLog("old block 0:  %s", sprint_hex(block0, sizeof(block0)));\r
	} else {\r
		PrintAndLog("Couldn't get old data. Will write over the last bytes of Block 0.");\r
	}\r
\r
	// fill in the new values\r
	// UID\r
	memcpy(block0, uid, 4); \r
	// Mifare UID BCC\r
	block0[4] = block0[0]^block0[1]^block0[2]^block0[3];\r
	// mifare classic SAK(byte 5) and ATQA(byte 6 and 7, reversed)\r
	if ( sak != NULL )\r
		block0[5]=sak[0];\r
	\r
	if ( atqa != NULL ) {\r
		block0[6]=atqa[1];\r
		block0[7]=atqa[0];\r
	}\r
	PrintAndLog("new block 0:  %s", sprint_hex(block0,16));\r
	\r
	if ( wipecard )		 params |= MAGIC_WIPE;	\r
	if ( oldUID == NULL) params |= MAGIC_UID;\r
	\r
	return mfCSetBlock(0, block0, oldUID, params);\r
}\r
\r
int mfCSetBlock(uint8_t blockNo, uint8_t *data, uint8_t *uid, uint8_t params) {\r
\r
	uint8_t isOK = 0;\r
	UsbCommand c = {CMD_MIFARE_CSETBLOCK, {params, blockNo, 0}};\r
	memcpy(c.d.asBytes, data, 16); \r
	clearCommandBuffer();\r
	SendCommand(&c);\r
	UsbCommand resp;\r
	if (WaitForResponseTimeout(CMD_ACK, &resp, 1500)) {\r
		isOK  = resp.arg[0] & 0xff;\r
		if (uid != NULL) \r
			memcpy(uid, resp.d.asBytes, 4);\r
		if (!isOK) \r
			return 2;\r
	} else {\r
		PrintAndLog("Command execute timeout");\r
		return 1;\r
	}\r
	return 0;\r
}\r
\r
int mfCGetBlock(uint8_t blockNo, uint8_t *data, uint8_t params) {\r
	uint8_t isOK = 0;\r
	UsbCommand c = {CMD_MIFARE_CGETBLOCK, {params, blockNo, 0}};	\r
	clearCommandBuffer();\r
	SendCommand(&c);\r
	UsbCommand resp;\r
	if (WaitForResponseTimeout(CMD_ACK,&resp,1500)) {\r
		isOK  = resp.arg[0] & 0xff;\r
		memcpy(data, resp.d.asBytes, 16);\r
		if (!isOK) return 2;\r
	} else {\r
		PrintAndLog("Command execute timeout");\r
		return 1;\r
	}\r
	return 0;\r
}\r
\r
// SNIFFER\r
\r
// constants\r
static uint8_t trailerAccessBytes[4] = {0x08, 0x77, 0x8F, 0x00};\r
\r
// variables\r
char logHexFileName[FILE_PATH_SIZE] = {0x00};\r
static uint8_t traceCard[4096] = {0x00};\r
static char traceFileName[FILE_PATH_SIZE] = {0x00};\r
static int traceState = TRACE_IDLE;\r
static uint8_t traceCurBlock = 0;\r
static uint8_t traceCurKey = 0;\r
\r
struct Crypto1State *traceCrypto1 = NULL;\r
\r
struct Crypto1State *revstate = NULL;\r
\r
uint64_t key = 0;\r
uint32_t ks2 = 0;\r
uint32_t ks3 = 0;\r
\r
uint32_t uid = 0;     // serial number\r
uint32_t nt =0;      // tag challenge\r
uint32_t nr_enc =0;  // encrypted reader challenge\r
uint32_t ar_enc =0;  // encrypted reader response\r
uint32_t at_enc =0;  // encrypted tag response\r
\r
int isTraceCardEmpty(void) {\r
	return ((traceCard[0] == 0) && (traceCard[1] == 0) && (traceCard[2] == 0) && (traceCard[3] == 0));\r
}\r
\r
int isBlockEmpty(int blockN) {\r
	for (int i = 0; i < 16; i++) \r
		if (traceCard[blockN * 16 + i] != 0) return 0;\r
\r
	return 1;\r
}\r
\r
int isBlockTrailer(int blockN) {\r
 return ((blockN & 0x03) == 0x03);\r
}\r
\r
int loadTraceCard(uint8_t *tuid) {\r
	FILE * f;\r
	char buf[64] = {0x00};\r
	uint8_t buf8[64] = {0x00};\r
	int i, blockNum;\r
	\r
	if (!isTraceCardEmpty()) \r
		saveTraceCard();\r
		\r
	memset(traceCard, 0x00, 4096);\r
	memcpy(traceCard, tuid + 3, 4);\r
\r
	FillFileNameByUID(traceFileName, tuid, ".eml", 7);\r
\r
	f = fopen(traceFileName, "r");\r
	if (!f) return 1;\r
	\r
	blockNum = 0;\r
		\r
	while(!feof(f)){\r
	\r
		memset(buf, 0, sizeof(buf));\r
		if (fgets(buf, sizeof(buf), f) == NULL) {\r
			PrintAndLog("File reading error.");\r
			fclose(f);\r
			return 2;\r
		}\r
\r
		if (strlen(buf) < 32){\r
			if (feof(f)) break;\r
			PrintAndLog("File content error. Block data must include 32 HEX symbols");\r
			fclose(f);\r
			return 2;\r
		}\r
		for (i = 0; i < 32; i += 2)\r
			sscanf(&buf[i], "%02x", (unsigned int *)&buf8[i / 2]);\r
\r
		memcpy(traceCard + blockNum * 16, buf8, 16);\r
\r
		blockNum++;\r
	}\r
	fclose(f);\r
\r
	return 0;\r
}\r
\r
int saveTraceCard(void) {\r
	FILE * f;\r
	\r
	if ((!strlen(traceFileName)) || (isTraceCardEmpty())) return 0;\r
	\r
	f = fopen(traceFileName, "w+");\r
	if ( !f ) return 1;\r
	\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
	}\r
	fclose(f);\r
	return 0;\r
}\r
\r
int mfTraceInit(uint8_t *tuid, uint8_t *atqa, uint8_t sak, bool wantSaveToEmlFile) {\r
\r
	if (traceCrypto1) \r
		crypto1_destroy(traceCrypto1);\r
\r
	traceCrypto1 = NULL;\r
\r
	if (wantSaveToEmlFile) \r
		loadTraceCard(tuid);\r
		\r
	traceCard[4] = traceCard[0] ^ traceCard[1] ^ traceCard[2] ^ traceCard[3];\r
	traceCard[5] = sak;\r
	memcpy(&traceCard[6], atqa, 2);\r
	traceCurBlock = 0;\r
	uid = bytes_to_num(tuid + 3, 4);\r
	\r
	traceState = TRACE_IDLE;\r
\r
	return 0;\r
}\r
\r
void mf_crypto1_decrypt(struct Crypto1State *pcs, uint8_t *data, int len, bool isEncrypted){\r
	uint8_t	bt = 0;\r
	int i;\r
	\r
	if (len != 1) {\r
		for (i = 0; i < len; i++)\r
			data[i] = crypto1_byte(pcs, 0x00, isEncrypted) ^ data[i];\r
	} else {\r
		bt = 0;\r
		for (i = 0; i < 4; i++)\r
			bt |= (crypto1_bit(pcs, 0, isEncrypted) ^ BIT(data[0], i)) << i;\r
				\r
		data[0] = bt;\r
	}\r
	return;\r
}\r
\r
\r
int mfTraceDecode(uint8_t *data_src, int len, bool wantSaveToEmlFile) {\r
	uint8_t data[64];\r
\r
	if (traceState == TRACE_ERROR) return 1;\r
	if (len > 64) {\r
		traceState = TRACE_ERROR;\r
		return 1;\r
	}\r
	\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
		AddLogHex(logHexFileName, "dec> ", data, len); \r
	}\r
	\r
	switch (traceState) {\r
	case TRACE_IDLE: \r
		// check packet crc16!\r
		if ((len >= 4) && (!CheckCrc14443(CRC_14443_A, data, len))) {\r
			PrintAndLog("dec> CRC ERROR!!!");\r
			AddLogLine(logHexFileName, "dec> ", "CRC ERROR!!!"); \r
			traceState = TRACE_ERROR;  // do not decrypt the next commands\r
			return 1;\r
		}\r
		\r
		// AUTHENTICATION\r
		if ((len == 4) && ((data[0] == 0x60) || (data[0] == 0x61))) {\r
			traceState = TRACE_AUTH1;\r
			traceCurBlock = data[1];\r
			traceCurKey = data[0] == 60 ? 1:0;\r
			return 0;\r
		}\r
\r
		// READ\r
		if ((len ==4) && ((data[0] == 0x30))) {\r
			traceState = TRACE_READ_DATA;\r
			traceCurBlock = data[1];\r
			return 0;\r
		}\r
\r
		// WRITE\r
		if ((len ==4) && ((data[0] == 0xA0))) {\r
			traceState = TRACE_WRITE_OK;\r
			traceCurBlock = data[1];\r
			return 0;\r
		}\r
\r
		// HALT\r
		if ((len ==4) && ((data[0] == 0x50) && (data[1] == 0x00))) {\r
			traceState = TRACE_ERROR;  // do not decrypt the next commands\r
			return 0;\r
		}\r
		\r
		return 0;\r
	break;\r
	\r
	case TRACE_READ_DATA: \r
		if (len == 18) {\r
			traceState = TRACE_IDLE;\r
\r
			if (isBlockTrailer(traceCurBlock)) {\r
				memcpy(traceCard + traceCurBlock * 16 + 6, data + 6, 4);\r
			} else {\r
				memcpy(traceCard + traceCurBlock * 16, data, 16);\r
			}\r
			if (wantSaveToEmlFile) saveTraceCard();\r
			return 0;\r
		} else {\r
			traceState = TRACE_ERROR;\r
			return 1;\r
		}\r
	break;\r
\r
	case TRACE_WRITE_OK: \r
		if ((len == 1) && (data[0] == 0x0a)) {\r
			traceState = TRACE_WRITE_DATA;\r
\r
			return 0;\r
		} else {\r
			traceState = TRACE_ERROR;\r
			return 1;\r
		}\r
	break;\r
\r
	case TRACE_WRITE_DATA: \r
		if (len == 18) {\r
			traceState = TRACE_IDLE;\r
\r
			memcpy(traceCard + traceCurBlock * 16, data, 16);\r
			if (wantSaveToEmlFile) saveTraceCard();\r
			return 0;\r
		} else {\r
			traceState = TRACE_ERROR;\r
			return 1;\r
		}\r
	break;\r
\r
	case TRACE_AUTH1: \r
		if (len == 4) {\r
			traceState = TRACE_AUTH2;\r
			nt = bytes_to_num(data, 4);\r
			return 0;\r
		} else {\r
			traceState = TRACE_ERROR;\r
			return 1;\r
		}\r
	break;\r
\r
	case TRACE_AUTH2: \r
		if (len == 8) {\r
			traceState = TRACE_AUTH_OK;\r
\r
			nr_enc = bytes_to_num(data, 4);\r
			ar_enc = bytes_to_num(data + 4, 4);\r
			return 0;\r
		} else {\r
			traceState = TRACE_ERROR;\r
			return 1;\r
		}\r
	break;\r
\r
	case TRACE_AUTH_OK: \r
		if (len ==4) {\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, &key);\r
			printf("Key: %012"llx"\n",key);\r
			AddLogUint64(logHexFileName, "key: ", key); \r
			\r
			int blockShift = ((traceCurBlock & 0xFC) + 3) * 16;\r
			if (isBlockEmpty((traceCurBlock & 0xFC) + 3)) memcpy(traceCard + blockShift + 6, trailerAccessBytes, 4);\r
			\r
			if (traceCurKey) {\r
				num_to_bytes(key, 6, traceCard + blockShift + 10);\r
			} else {\r
				num_to_bytes(key, 6, traceCard + blockShift);\r
			}\r
			if (wantSaveToEmlFile) saveTraceCard();\r
\r
			if (traceCrypto1) {\r
				crypto1_destroy(traceCrypto1);\r
			}\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(key); // 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 1;\r
		}\r
	break;\r
\r
	default: \r
		traceState = TRACE_ERROR;\r
		return 1;\r
	}\r
\r
	return 0;\r
}\r
\r
int tryDecryptWord(uint32_t nt, uint32_t ar_enc, uint32_t at_enc, uint8_t *data, int len){\r
	/*\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
	*/\r
\r
	struct Crypto1State *pcs = NULL;\r
	\r
	ks2 = ar_enc ^ prng_successor(nt, 64);\r
	ks3 = at_enc ^ prng_successor(nt, 96);\r
	\r
	PrintAndLog("Decrypting data with:");\r
	PrintAndLog("      nt: %08x",nt);\r
	PrintAndLog("  ar_enc: %08x",ar_enc);\r
	PrintAndLog("  at_enc: %08x",at_enc);\r
	PrintAndLog("\nEncrypted data: [%s]", sprint_hex(data,len) );\r
\r
	pcs = lfsr_recovery64(ks2, ks3);\r
	mf_crypto1_decrypt(pcs, data, len, FALSE);\r
	PrintAndLog("Decrypted data: [%s]", sprint_hex(data,len) );\r
	crypto1_destroy(pcs);\r
	return 0;\r
}\r