proxmark3/tools/nonce2key/nonce2key.c

#include "crapto1.h"
#define __STDC_FORMAT_MACROS
#include <inttypes.h>
#include <stdio.h>

int main(const int argc, const char* argv[]) {
	struct Crypto1State *state;
	uint32_t pos, uid, nt, nr, rr, nr_diff;
	uint8_t bt, i, ks3x[8], par[8][8];
	uint64_t key_recovered;
	uint64_t par_info;
	uint64_t ks_info;
	nr = rr = 0;

	if (argc < 5) {
		printf("\nsyntax: %s <uid> <nt> <par> <ks>\n\n",argv[0]);
		return 1;
	}
	sscanf(argv[1],"%08x", &uid);
	sscanf(argv[2],"%08x", &nt);
	sscanf(argv[3],"%016" SCNx64 ,&par_info);
	sscanf(argv[4],"%016" SCNx64 ,&ks_info);
  
	// Reset the last three significant bits of the reader nonce
	nr &= 0xffffff1f;

	printf("\nuid(%08x) nt(%08x) par(%016" PRIx64 ") ks(%016" PRIx64 ")\n\n", uid, nt, par_info, ks_info);

	for ( pos = 0; pos < 8; pos++ ) {
		ks3x[7-pos] = (ks_info >> (pos*8)) & 0x0f;
		bt = (par_info >> (pos*8)) & 0xff;

		for ( i = 0; i < 8; i++) {
			par[7-pos][i] = (bt >> i) & 0x01;
		}
	}

	printf("|diff|{nr}    |ks3|ks3^5|parity         |\n");
	printf("+----+--------+---+-----+---------------+\n");

	for ( i = 0; i < 8; i++) {
		nr_diff = nr | i << 5;
		printf("| %02x |%08x| %01x |  %01x  |", i << 5, nr_diff, ks3x[i], ks3x[i]^5);

		for ( pos = 0; pos < 7; pos++)
			printf("%01x,", par[i][pos]);
		printf("%01x|\n", par[i][7]);
	}
	printf("+----+--------+---+-----+---------------+\n");
 
	state = lfsr_common_prefix(nr,rr,ks3x,par);
	lfsr_rollback_word(state,uid^nt,0);
	crypto1_get_lfsr(state,&key_recovered);
	printf("\nkey recovered: %012" PRIx64 "\n\n", key_recovered);
	crypto1_destroy(state);
	return 0;
}