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[proxmark3-svn] / tools / mfkey / mfkey64.c
1 #define __STDC_FORMAT_MACROS
2 #include <stdio.h>
3 #include <string.h>
4 #include <time.h>
5 #include <inttypes.h>
6 #include "crapto1.h"
7
8 #define llx PRIx64
9 #define lli PRIi64
10
11 int main (int argc, char *argv[]) {
12 struct Crypto1State *revstate;
13 uint64_t key; // recovered key
14 uint32_t uid; // serial number
15 uint32_t nt; // tag challenge
16 uint32_t nr_enc; // encrypted reader challenge
17 uint32_t ar_enc; // encrypted reader response
18 uint32_t at_enc; // encrypted tag response
19 uint32_t ks2; // keystream used to encrypt reader response
20 uint32_t ks3; // keystream used to encrypt tag response
21
22 printf("MIFARE Classic key recovery - based 64 bits of keystream\n");
23 printf("Recover key from only one complete authentication!\n\n");
24
25 if (argc < 6) {
26 printf(" syntax: %s <uid> <nt> <{nr}> <{ar}> <{at}> [enc...]\n\n", argv[0]);
27 return 1;
28 }
29
30 int encc = argc - 6;
31 int enclen[encc];
32 uint8_t enc[encc][120];
33
34 sscanf(argv[1],"%x",&uid);
35 sscanf(argv[2],"%x",&nt);
36 sscanf(argv[3],"%x",&nr_enc);
37 sscanf(argv[4],"%x",&ar_enc);
38 sscanf(argv[5],"%x",&at_enc);
39 for (int i = 0; i < encc; i++) {
40 enclen[i] = strlen(argv[i + 6]) / 2;
41 for (int i2 = 0; i2 < enclen[i]; i2++) {
42 sscanf(argv[i+6] + i2*2, "%2x", (unsigned int *)&enc[i][i2]);
43 }
44 }
45
46 printf("Recovering key for:\n");
47
48 printf(" uid: %08x\n",uid);
49 printf(" nt: %08x\n",nt);
50 printf(" {nr}: %08x\n",nr_enc);
51 printf(" {ar}: %08x\n",ar_enc);
52 printf(" {at}: %08x\n",at_enc);
53
54 for (int i = 0; i < encc; i++) {
55 printf("{enc%d}: ", i);
56 for (int i2 = 0; i2 < enclen[i]; i2++) {
57 printf("%02x", enc[i][i2]);
58 }
59 printf("\n");
60 }
61
62 // Generate lfsr succesors of the tag challenge
63 printf("\nLFSR succesors of the tag challenge:\n");
64 printf(" nt': %08x\n",prng_successor(nt, 64));
65 printf(" nt'': %08x\n",prng_successor(nt, 96));
66
67 clock_t t1 = clock();
68
69 // Extract the keystream from the messages
70 printf("\nKeystream used to generate {ar} and {at}:\n");
71 ks2 = ar_enc ^ prng_successor(nt, 64);
72 ks3 = at_enc ^ prng_successor(nt, 96);
73 printf(" ks2: %08x\n",ks2);
74 printf(" ks3: %08x\n",ks3);
75
76 revstate = lfsr_recovery64(ks2, ks3);
77
78 // Decrypting communication using keystream if presented
79 if (argc > 6 ) {
80 printf("\nDecrypted communication:\n");
81 uint8_t ks4;
82 int rollb = 0;
83 for (int i = 0; i < encc; i++) {
84 printf("{dec%d}: ", i);
85 for (int i2 = 0; i2 < enclen[i]; i2++) {
86 ks4 = crypto1_byte(revstate, 0, 0);
87 printf("%02x", ks4 ^ enc[i][i2]);
88 rollb += 1;
89 }
90 printf("\n");
91 }
92 for (int i = 0; i < rollb; i++)
93 lfsr_rollback_byte(revstate, 0, 0);
94 }
95
96 lfsr_rollback_word(revstate, 0, 0);
97 lfsr_rollback_word(revstate, 0, 0);
98 lfsr_rollback_word(revstate, nr_enc, 1);
99 lfsr_rollback_word(revstate, uid ^ nt, 0);
100 crypto1_get_lfsr(revstate, &key);
101 printf("\nFound Key: [%012"llx"]\n\n", key);
102 crypto1_destroy(revstate);
103
104 t1 = clock() - t1;
105 if ( t1 > 0 ) printf("Time : %.0f ticks \n", (float)t1);
106 return 0;
107 }
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