proxmark3/tools/mfkey/mfkey32.c
2020-05-11 14:46:22 +02:00

78 lines
2.2 KiB
C
Executable File

#include <inttypes.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include "crapto1/crapto1.h"
#include "mifare/mfkey.h"
#include "util_posix.h"
// 32 bit recover key from 2 nonces
int main (int argc, char *argv[]) {
nonces_t data = {0};
uint32_t ks2; // keystream used to encrypt reader response
uint64_t key; // recovered key
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 && argc != 8) {
printf(" syntax: %s <uid> <nt0> <{nr_0}> <{ar_0}> [<nt1>] <{nr_1}> <{ar_1}>\n", argv[0]);
printf(" (you may omit nt1 if it is equal to nt0)\n\n");
return 1;
}
bool moebius_attack = (argc == 8);
sscanf(argv[1],"%" SCNx32, &data.cuid);
sscanf(argv[2],"%" SCNx32, &data.nonce);
data.nonce2 = data.nonce;
sscanf(argv[3],"%" SCNx32, &data.nr);
sscanf(argv[4],"%" SCNx32, &data.ar);
if (moebius_attack) {
sscanf(argv[5],"%" SCNx32, &data.nonce2);
sscanf(argv[6],"%" SCNx32, &data.nr2);
sscanf(argv[7],"%" SCNx32, &data.ar2);
} else {
sscanf(argv[5],"%" SCNx32, &data.nr2);
sscanf(argv[6],"%" SCNx32, &data.ar2);
}
printf("Recovering key for:\n");
printf(" uid: %08x\n",data.cuid);
printf(" nt0: %08x\n",data.nonce);
printf(" {nr_0}: %08x\n",data.nr);
printf(" {ar_0}: %08x\n",data.ar);
printf(" nt1: %08x\n",data.nonce2);
printf(" {nr_1}: %08x\n",data.nr2);
printf(" {ar_1}: %08x\n",data.ar2);
uint64_t start_time = msclock();
// Generate lfsr succesors of the tag challenge
printf("\nLFSR succesors of the tag challenge:\n");
printf(" nt': %08x\n",prng_successor(data.nonce, 64));
printf(" nt'': %08x\n",prng_successor(data.nonce, 96));
// Extract the keystream from the messages
printf("\nKeystream used to generate {ar} and {at}:\n");
ks2 = data.ar ^ prng_successor(data.nonce, 64);
printf(" ks2: %08x\n",ks2);
bool success;
if (moebius_attack) {
success = mfkey32_moebius(data, &key);
} else {
success = mfkey32(data, &key);
}
if (success) {
printf("Recovered key: %012" PRIx64 "\n", key);
} else {
printf("Couldn't recover key.\n");
}
printf("Time spent: %1.2f seconds\n", (float)(msclock() - start_time)/1000.0);
}