proxmark3/tools/mfc/card_reader/mfkey32.c
2024-09-02 11:11:40 +02:00

72 lines
2.4 KiB
C

#define __STDC_FORMAT_MACROS
#include <inttypes.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include "crapto1/crapto1.h"
#include "util_posix.h"
int main(int argc, char *argv[]) {
struct Crypto1State *s, *t;
uint64_t key; // recovered key
uint32_t uid; // serial number
uint32_t nt; // tag challenge
uint32_t nr0_enc; // first encrypted reader challenge
uint32_t ar0_enc; // first encrypted reader response
uint32_t nr1_enc; // second encrypted reader challenge
uint32_t ar1_enc; // second encrypted reader response
uint32_t ks2_0; // first keystream used to encrypt reader response
uint32_t ks2_1; // second keystream used to encrypt reader response
printf("MIFARE Classic key recovery - based on 32 bits of keystream\n");
printf("Recover key from two 32-bit reader authentication answers only!\n\n");
if (argc < 7) {
printf(" syntax: %s <uid> <nt> <{nr_0}> <{ar}_0> <{nr_1}> <{ar}_0>\n\n", argv[0]);
return 1;
}
sscanf(argv[1], "%x", &uid);
sscanf(argv[2], "%x", &nt);
sscanf(argv[3], "%x", &nr0_enc);
sscanf(argv[4], "%x", &ar0_enc);
sscanf(argv[5], "%x", &nr1_enc);
sscanf(argv[6], "%x", &ar1_enc);
printf("Recovering key for:\n");
printf(" uid: %08x\n", uid);
printf(" nt: %08x\n", nt);
printf(" {nr_0}: %08x\n", nr0_enc);
printf(" {ar}_0: %08x\n", ar0_enc);
printf(" {nr_1}: %08x\n", nr1_enc);
printf(" {ar}_1: %08x\n", ar1_enc);
// Generate lfsr successors of the tag challenge
printf("\nLFSR successor of the tag challenge:\n");
uint32_t ar = prng_successor(nt, 64);
printf(" ar: %08x\n", ar);
// Extract the keystream from the messages
printf("\nKeystreams used to generate {ar}_0 and {ar}_1:\n");
ks2_0 = ar0_enc ^ ar;
printf(" ks2_0: %08x\n", ks2_0);
ks2_1 = ar1_enc ^ ar;
printf(" ks2_1: %08x\n", ks2_1);
s = lfsr_recovery32(ks2_0, 0);
for (t = s; t->odd | t->even; ++t) {
lfsr_rollback_word(t, 0, 0);
lfsr_rollback_word(t, nr0_enc, 1);
lfsr_rollback_word(t, uid ^ nt, 0);
crypto1_get_lfsr(t, &key);
crypto1_word(t, uid ^ nt, 0);
crypto1_word(t, nr1_enc, 1);
if (ks2_1 == crypto1_word(t, 0, 0)) {
printf("\nFound Key: [%012" PRIx64 "]\n\n", key);
break;
}
}
free(s);
return 0;
}