proxmark3/tools/mfc/card_only/nonce2key.c

#include "crapto1/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;
    uint8_t 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", argv[0]);
        printf("example: %s 92c0456b 73294ab7 a3fbfb537343eb7b 070608090e060a02\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;
        uint8_t bt = (par_info >> (pos * 8)) & 0xff;

        for (uint8_t i = 0; i < 8; i++) {
            par[7 - pos][i] = (bt >> i) & 0x01;
        }
    }

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

    for (uint8_t i = 0; i < 8; i++) {
        uint32_t 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, false);
    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;
}