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1 /*****************************************************************************

2 * WARNING

3 *

4 * THIS CODE IS CREATED FOR EXPERIMENTATION AND EDUCATIONAL USE ONLY.

5 *

6 * USAGE OF THIS CODE IN OTHER WAYS MAY INFRINGE UPON THE INTELLECTUAL

7 * PROPERTY OF OTHER PARTIES, SUCH AS INSIDE SECURE AND HID GLOBAL,

8 * AND MAY EXPOSE YOU TO AN INFRINGEMENT ACTION FROM THOSE PARTIES.

9 *

10 * THIS CODE SHOULD NEVER BE USED TO INFRINGE PATENTS OR INTELLECTUAL PROPERTY RIGHTS.

11 *

12 *****************************************************************************

13 *

14 * This file is part of loclass. It is a reconstructon of the cipher engine

15 * used in iClass, and RFID techology.

16 *

17 * The implementation is based on the work performed by

18 * Flavio D. Garcia, Gerhard de Koning Gans, Roel Verdult and

19 * Milosch Meriac in the paper "Dismantling IClass".

20 *

22 *

23 * This is free software: you can redistribute it and/or modify

24 * it under the terms of the GNU General Public License version 2 as published

25 * by the Free Software Foundation, or, at your option, any later version.

26 *

27 * This file is distributed in the hope that it will be useful,

28 * but WITHOUT ANY WARRANTY; without even the implied warranty of

29 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the

30 * GNU General Public License for more details.

31 *

32 * You should have received a copy of the GNU General Public License

33 * along with loclass. If not, see <http://www.gnu.org/licenses/>.

34 *

35 *

36 ****************************************************************************/

38 #ifndef OPTIMIZED_CIPHER_H__

39 #define OPTIMIZED_CIPHER_H__

41 #include <stdint.h>

43 /**

44 * Definition 1 (Cipher state). A cipher state of iClass s is an element of F 40/2

45 * consisting of the following four components:

46 * 1. the left register l = (l 0 . . . l 7 ) ∈ F 8/2 ;

47 * 2. the right register r = (r 0 . . . r 7 ) ∈ F 8/2 ;

48 * 3. the top register t = (t 0 . . . t 15 ) ∈ F 16/2 .

49 * 4. the bottom register b = (b 0 . . . b 7 ) ∈ F 8/2 .

50 **/

51 typedef struct {

52 uint8_t l;

53 uint8_t r;

54 uint8_t b;

55 uint16_t t;

56 } State;

58 /** The reader MAC is MAC(key, CC * NR )

59 **/

 void opt_doReaderMAC(uint8_t *cc_nr_p, uint8_t *div_key_p, uint8_t mac[4]);

62 /**

63 * The tag MAC is MAC(key, CC * NR * 32x0))

64 */

 void opt_doTagMAC(uint8_t *cc_p, const uint8_t *div_key_p, uint8_t mac[4]);

67 /**

68 * The tag MAC can be divided (both can, but no point in dividing the reader mac) into

69 * two functions, since the first 8 bytes are known, we can pre-calculate the state

70 * reached after feeding CC to the cipher.

71 * @param cc_p

72 * @param div_key_p

73 * @return the cipher state

74 */

 State opt_doTagMAC_1(uint8_t *cc_p, const uint8_t *div_key_p);

77 /**

78 * The second part of the tag MAC calculation, since the CC is already calculated into the state,

79 * this function is fed only the NR, and internally feeds the remaining 32 0-bits to generate the tag

80 * MAC response.

81 * @param _init - precalculated cipher state

82 * @param nr - the reader challenge

83 * @param mac - where to store the MAC

84 * @param div_key_p - the key to use

85 */

 void opt_doTagMAC_2(State _init, uint8_t *nr, uint8_t mac[4], const uint8_t *div_key_p);

88 #endif // OPTIMIZED_CIPHER_H__