proxmark3/tools/mfkey/mfkey64.c
Philippe Teuwen 88308ea727 typos
2021-10-10 01:35:45 +02:00

102 lines
3.1 KiB
C

#define __STDC_FORMAT_MACROS
#include <inttypes.h>
#include <stdbool.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include "crapto1/crapto1.h"
#include "util_posix.h"
int main(int argc, char *argv[]) {
struct Crypto1State *revstate;
uint64_t key; // recovered key
uint32_t uid; // serial number
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
uint32_t ks2; // keystream used to encrypt reader response
uint32_t ks3; // keystream used to encrypt tag response
printf("MIFARE Classic key recovery - based 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...]\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, "%2hhx", &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");
}
// Generate lfsr successors of the tag challenge
printf("\nLFSR successors of the tag challenge:\n");
uint32_t p64 = prng_successor(nt, 64);
printf(" nt': %08x\n", p64);
printf(" nt'': %08x\n", prng_successor(p64, 32));
// Extract the keystream from the messages
printf("\nKeystream used to generate {ar} and {at}:\n");
ks2 = ar_enc ^ p64;
ks3 = at_enc ^ prng_successor(p64, 32);
printf(" ks2: %08x\n", ks2);
printf(" ks3: %08x\n", ks3);
revstate = lfsr_recovery64(ks2, 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);
printf("\nFound Key: [%012" PRIx64 "]\n\n", key);
crypto1_destroy(revstate);
return 0;
}