armsrc/optimized_cipher.h

   1 #ifndef OPTIMIZED_CIPHER_H
   2 #define OPTIMIZED_CIPHER_H
   3
   4 #include "common.h"
   5 #include "string.h"
   6 /**
   7 * Definition 1 (Cipher state). A cipher state of iClass s is an element of F 40/2
   8 * consisting of the following four components:
   9 *   1. the left register l = (l 0 . . . l 7 ) ∈ F 8/2 ;
  10 *   2. the right register r = (r 0 . . . r 7 ) ∈ F 8/2 ;
  11 *   3. the top register t = (t 0 . . . t 15 ) ∈ F 16/2 .
  12 *   4. the bottom register b = (b 0 . . . b 7 ) ∈ F 8/2 .
  13 **/
  14 typedef struct {
  15     uint8_t l;
  16     uint8_t r;
  17     uint8_t b;
  18     uint16_t t;
  19 } State;
  20
  21 /** The reader MAC is MAC(key, CC * NR )
  22  **/
  23 void opt_doReaderMAC(uint8_t *cc_nr_p, uint8_t *div_key_p, uint8_t mac[4]);
  24
  25 void opt_doReaderMAC_2(State _init,  uint8_t *nr, uint8_t mac[4], const uint8_t *div_key_p);
  26
  27 /**
  28  * The tag MAC is MAC(key, CC * NR * 32x0))
  29  */
  30 void opt_doTagMAC(uint8_t *cc_p, const uint8_t *div_key_p, uint8_t mac[4]);
  31
  32 /**
  33  * The tag MAC can be divided (both can, but no point in dividing the reader mac) into
  34  * two functions, since the first 8 bytes are known, we can pre-calculate the state
  35  * reached after feeding CC to the cipher.
  36  * @param cc_p
  37  * @param div_key_p
  38  * @return the cipher state
  39  */
  40 State opt_doTagMAC_1(uint8_t *cc_p, const uint8_t *div_key_p);
  41 /**
  42  * The second part of the tag MAC calculation, since the CC is already calculated into the state,
  43  * this function is fed only the NR, and internally feeds the remaining 32 0-bits to generate the tag
  44  * MAC response.
  45  * @param _init - precalculated cipher state
  46  * @param nr - the reader challenge
  47  * @param mac - where to store the MAC
  48  * @param div_key_p - the key to use
  49  */
  50 void opt_doTagMAC_2(State _init, uint8_t *nr, uint8_t mac[4], const uint8_t *div_key_p);
  51
  52 void doMAC_N(uint8_t *in_p, uint8_t in_size, uint8_t *div_key_p, uint8_t mac[4]);
  53 void iclass_calc_div_key(uint8_t *csn, uint8_t *key, uint8_t *div_key, bool elite);
  54 #endif // OPTIMIZED_CIPHER_H