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[proxmark3-svn] / tools / mfkey / mfkey32.c
1 #include <inttypes.h>
2 #include "crapto1/crapto1.h"
3 #include <stdio.h>
4 #include <stdlib.h>
5
6 int main (int argc, char *argv[]) {
7 struct Crypto1State *s,*t;
8 uint64_t key; // recovered key
9 uint32_t uid; // serial number
10 uint32_t nt; // tag challenge
11 uint32_t nr0_enc; // first encrypted reader challenge
12 uint32_t ar0_enc; // first encrypted reader response
13 uint32_t nr1_enc; // second encrypted reader challenge
14 uint32_t ar1_enc; // second encrypted reader response
15 uint32_t ks2; // keystream used to encrypt reader response
16
17 printf("MIFARE Classic key recovery - based 32 bits of keystream\n");
18 printf("Recover key from two 32-bit reader authentication answers only!\n\n");
19
20 if (argc < 7) {
21 printf(" syntax: %s <uid> <nt> <{nr_0}> <{ar_0}> <{nr_1}> <{ar_1}>\n\n",argv[0]);
22 return 1;
23 }
24
25 sscanf(argv[1],"%x",&uid);
26 sscanf(argv[2],"%x",&nt);
27 sscanf(argv[3],"%x",&nr0_enc);
28 sscanf(argv[4],"%x",&ar0_enc);
29 sscanf(argv[5],"%x",&nr1_enc);
30 sscanf(argv[6],"%x",&ar1_enc);
31
32 printf("Recovering key for:\n");
33 printf(" uid: %08x\n",uid);
34 printf(" nt: %08x\n",nt);
35 printf(" {nr_0}: %08x\n",nr0_enc);
36 printf(" {ar_0}: %08x\n",ar0_enc);
37 printf(" {nr_1}: %08x\n",nr1_enc);
38 printf(" {ar_1}: %08x\n",ar1_enc);
39
40 // Generate lfsr succesors of the tag challenge
41 printf("\nLFSR succesors of the tag challenge:\n");
42 printf(" nt': %08x\n",prng_successor(nt, 64));
43 printf(" nt'': %08x\n",prng_successor(nt, 96));
44
45 // Extract the keystream from the messages
46 printf("\nKeystream used to generate {ar} and {at}:\n");
47 ks2 = ar0_enc ^ prng_successor(nt, 64);
48 printf(" ks2: %08x\n",ks2);
49
50 s = lfsr_recovery32(ar0_enc ^ prng_successor(nt, 64), 0);
51
52 for(t = s; t->odd | t->even; ++t) {
53 lfsr_rollback_word(t, 0, 0);
54 lfsr_rollback_word(t, nr0_enc, 1);
55 lfsr_rollback_word(t, uid ^ nt, 0);
56 crypto1_get_lfsr(t, &key);
57 crypto1_word(t, uid ^ nt, 0);
58 crypto1_word(t, nr1_enc, 1);
59 if (ar1_enc == (crypto1_word(t, 0, 0) ^ prng_successor(nt, 64))) {
60 printf("\nFound Key: [%012" PRIx64 "]\n\n",key);
61 break;
62 }
63 }
64 free(s);
65
66 return 0;
67 }
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