Merge pull request #246 from marshmellow42/master

[proxmark3-svn] / tools / mfkey / mfkey64.c

#include <stdio.h>
#include <strings.h>
#include <inttypes.h>
#include "crapto1/crapto1.h"
#include "util.h"

int main (int argc, char *argv[]) 
{
	uint32_t uid;     // serial numDber
	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
	uint64_t key 	= 0;				// recovered key
	struct Crypto1State *revstate;
	uint32_t ks2;     					// keystream used to encrypt reader response
	uint32_t ks3;     					// keystream used to encrypt tag response

	printf("MIFARE Classic key recovery - based on 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", (unsigned int*)&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");
	}

	printf("\nLFSR successors 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
	ks2 = ar_enc ^ prng_successor(nt, 64);
	ks3 = at_enc ^ prng_successor(nt, 96);
	
	uint64_t start_time = msclock();
	revstate = lfsr_recovery64(ks2, ks3);
	uint64_t time_spent = msclock() - start_time;
	printf("Time spent in lfsr_recovery64(): %1.2f seconds\n", (float)time_spent/1000.0);
	printf("\nKeystream used to generate {ar} and {at}:\n");
	printf("   ks2: %08x\n",ks2);
	printf("   ks3: %08x\n",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);
	crypto1_destroy(revstate);

	printf("\nFound Key: [%012" PRIx64"]\n\n",key);
	
}