4e9876c50524fe5ac0a9d9a8f86f4946822babe5
[proxmark3-svn] / tools / mfkey / mfkey64.c
1 #include <stdio.h>
2 #include <strings.h>
3 #include <inttypes.h>
4 #include "crapto1/crapto1.h"
5 #include "util.h"
6
7 int main (int argc, char *argv[])
8 {
9 uint32_t uid; // serial numDber
10 uint32_t nt; // tag challenge
11 uint32_t nr_enc; // encrypted reader challenge
12 uint32_t ar_enc; // encrypted reader response
13 uint32_t at_enc; // encrypted tag response
14 uint64_t key = 0; // recovered key
15 struct Crypto1State *revstate;
16 uint32_t ks2; // keystream used to encrypt reader response
17 uint32_t ks3; // keystream used to encrypt tag response
18
19 printf("MIFARE Classic key recovery - based on 64 bits of keystream\n");
20 printf("Recover key from only one complete authentication!\n\n");
21
22 if (argc < 6 ) {
23 printf(" syntax: %s <uid> <nt> <{nr}> <{ar}> <{at}> [enc] [enc...]\n\n", argv[0]);
24 return 1;
25 }
26
27 int encc = argc - 6;
28 int enclen[encc];
29 uint8_t enc[encc][120];
30
31 sscanf(argv[1], "%x", &uid);
32 sscanf(argv[2], "%x", &nt);
33 sscanf(argv[3], "%x", &nr_enc);
34 sscanf(argv[4], "%x", &ar_enc);
35 sscanf(argv[5], "%x", &at_enc);
36 for (int i = 0; i < encc; i++) {
37 enclen[i] = strlen(argv[i + 6]) / 2;
38 for (int i2 = 0; i2 < enclen[i]; i2++) {
39 sscanf(argv[i+6] + i2*2,"%2x", (unsigned int*)&enc[i][i2]);
40 }
41 }
42
43 printf("Recovering key for:\n");
44 printf(" uid: %08x\n", uid);
45 printf(" nt: %08x\n", nt);
46 printf(" {nr}: %08x\n", nr_enc);
47 printf(" {ar}: %08x\n", ar_enc);
48 printf(" {at}: %08x\n", at_enc);
49 for (int i = 0; i < encc; i++) {
50 printf("{enc%d}: ", i);
51 for (int i2 = 0; i2 < enclen[i]; i2++) {
52 printf("%02x", enc[i][i2]);
53 }
54 printf("\n");
55 }
56
57 printf("\nLFSR successors of the tag challenge:\n");
58 printf(" nt' : %08x\n",prng_successor(nt, 64));
59 printf(" nt'': %08x\n",prng_successor(nt, 96));
60
61 // Extract the keystream from the messages
62 ks2 = ar_enc ^ prng_successor(nt, 64);
63 ks3 = at_enc ^ prng_successor(nt, 96);
64
65 uint64_t start_time = msclock();
66 revstate = lfsr_recovery64(ks2, ks3);
67 uint64_t time_spent = msclock() - start_time;
68 printf("Time spent in lfsr_recovery64(): %1.2f seconds\n", (float)time_spent/1000.0);
69 printf("\nKeystream used to generate {ar} and {at}:\n");
70 printf(" ks2: %08x\n",ks2);
71 printf(" ks3: %08x\n",ks3);
72
73 // Decrypting communication using keystream if presented
74 if (argc > 6 ) {
75 printf("\nDecrypted communication:\n");
76 uint8_t ks4;
77 int rollb = 0;
78 for (int i = 0; i < encc; i++) {
79 printf("{dec%d}: ", i);
80 for (int i2 = 0; i2 < enclen[i]; i2++) {
81 ks4 = crypto1_byte(revstate, 0, 0);
82 printf("%02x", ks4 ^ enc[i][i2]);
83 rollb += 1;
84 }
85 printf("\n");
86 }
87 for (int i = 0; i < rollb; i++) {
88 lfsr_rollback_byte(revstate, 0, 0);
89 }
90 }
91
92 lfsr_rollback_word(revstate, 0, 0);
93 lfsr_rollback_word(revstate, 0, 0);
94 lfsr_rollback_word(revstate, nr_enc, 1);
95 lfsr_rollback_word(revstate, uid ^ nt, 0);
96 crypto1_get_lfsr(revstate, &key);
97 crypto1_destroy(revstate);
98
99 printf("\nFound Key: [%012" PRIx64"]\n\n",key);
100
101 }
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