cvs.zerfleddert.de Git - proxmark3-svn/blob - armsrc/optimized_cipher.h

   1 #ifndef OPTIMIZED_CIPHER_H
   2 #define OPTIMIZED_CIPHER_H
   3
   4 #include <stdint.h>
   5 #include <stdlib.h>
   6 #include <string.h>
   7 #include <stdbool.h>
   8
   9 /**
  10 * Definition 1 (Cipher state). A cipher state of iClass s is an element of F 40/2
  11 * consisting of the following four components:
  12 *       1. the left register l = (l 0 . . . l 7 ) ∈ F 8/2 ;
  13 *       2. the right register r = (r 0 . . . r 7 ) ∈ F 8/2 ;
  14 *       3. the top register t = (t 0 . . . t 15 ) ∈ F 16/2 .
  15 *       4. the bottom register b = (b 0 . . . b 7 ) ∈ F 8/2 .
  16 **/
  17 typedef struct {
  18         uint8_t l;
  19         uint8_t r;
  20         uint8_t b;
  21         uint16_t t;
  22 } State;
  23
  24 /** The reader MAC is MAC(key, CC * NR )
  25  **/
  26 void opt_doReaderMAC(uint8_t *cc_nr_p, uint8_t *div_key_p, uint8_t mac[4]);
  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 #endif // OPTIMIZED_CIPHER_H