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Commit	Line	Data
	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