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