]> git.zerfleddert.de Git - proxmark3-svn/blob - armsrc/optimized_cipher.h
fix issue #103: revert type change. Samples from FPGA are signed.
[proxmark3-svn] / armsrc / optimized_cipher.h
1 #ifndef OPTIMIZED_CIPHER_H
2 #define OPTIMIZED_CIPHER_H
3 #include <stdint.h>
4
5 /**
6 * Definition 1 (Cipher state). A cipher state of iClass s is an element of F 40/2
7 * consisting of the following four components:
8 * 1. the left register l = (l 0 . . . l 7 ) ∈ F 8/2 ;
9 * 2. the right register r = (r 0 . . . r 7 ) ∈ F 8/2 ;
10 * 3. the top register t = (t 0 . . . t 15 ) ∈ F 16/2 .
11 * 4. the bottom register b = (b 0 . . . b 7 ) ∈ F 8/2 .
12 **/
13 typedef struct {
14 uint8_t l;
15 uint8_t r;
16 uint8_t b;
17 uint16_t t;
18 } State;
19
20 /** The reader MAC is MAC(key, CC * NR )
21 **/
22 void opt_doReaderMAC(uint8_t *cc_nr_p, uint8_t *div_key_p, uint8_t mac[4]);
23 /**
24 * The tag MAC is MAC(key, CC * NR * 32x0))
25 */
26 void opt_doTagMAC(uint8_t *cc_p, const uint8_t *div_key_p, uint8_t mac[4]);
27
28 /**
29 * The tag MAC can be divided (both can, but no point in dividing the reader mac) into
30 * two functions, since the first 8 bytes are known, we can pre-calculate the state
31 * reached after feeding CC to the cipher.
32 * @param cc_p
33 * @param div_key_p
34 * @return the cipher state
35 */
36 State opt_doTagMAC_1(uint8_t *cc_p, const uint8_t *div_key_p);
37 /**
38 * The second part of the tag MAC calculation, since the CC is already calculated into the state,
39 * this function is fed only the NR, and internally feeds the remaining 32 0-bits to generate the tag
40 * MAC response.
41 * @param _init - precalculated cipher state
42 * @param nr - the reader challenge
43 * @param mac - where to store the MAC
44 * @param div_key_p - the key to use
45 */
46 void opt_doTagMAC_2(State _init, uint8_t* nr, uint8_t mac[4], const uint8_t* div_key_p);
47
48 #endif // OPTIMIZED_CIPHER_H
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