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#include <stdint.h>
#include <string.h>
#include "parameters.h"
#include "tweakey.h"
#define LANE_BITS 64
#define LANE_BYTES (LANE_BITS/8)
#define LANES_NB (TWEAKEY_BYTES/LANE_BYTES)
void tweakey_state_init(
uint8_t TK[TWEAKEY_BYTES],
const uint8_t key[KEY_BYTES],
const uint8_t tweak[TWEAK_BYTES]
)
{
memcpy(TK, tweak, TWEAK_BYTES);
memcpy(TK+TWEAK_BYTES, key, KEY_BYTES);
}
void tweakey_state_extract(
const uint8_t TK[TWEAKEY_BYTES],
uint8_t round_constant,
uint8_t round_tweakey[ROUND_TWEAKEY_BYTES]
)
{
memset(round_tweakey, 0, ROUND_TWEAKEY_BYTES);
for (size_t j=0; j<LANES_NB; j++)
{
const uint8_t *TKj = TK + j*LANE_BYTES;
for (size_t k=0; k<LANE_BYTES; k++)
{
round_tweakey[k] ^= TKj[k];
}
}
round_tweakey[0] ^= round_constant;
}
static void _multiply_M(const uint8_t old[LANE_BYTES], uint8_t new[LANE_BYTES])
{
new[7] = old[6];
new[6] = old[5];
new[5] = old[4] ^ old[5]<<3;
new[4] = old[3] ^ old[4]>>3;
new[3] = old[2];
new[2] = old[1] ^ old[6]<<2;
new[1] = old[0];
new[0] = old[7];
}
static void _multiply_M2(const uint8_t old[LANE_BYTES], uint8_t new[LANE_BYTES])
{
uint8_t tmp[LANE_BYTES];
memcpy(tmp, old, LANE_BYTES);
_multiply_M(old, tmp);
_multiply_M(tmp, new);
}
static void _multiply_M3(const uint8_t old[LANE_BYTES], uint8_t new[LANE_BYTES])
{
uint8_t tmp[LANE_BYTES];
memcpy(tmp, old, LANE_BYTES);
_multiply_M2(old, tmp);
_multiply_M(tmp, new);
}
static void _multiply_MR(const uint8_t old[LANE_BYTES], uint8_t new[LANE_BYTES])
{
new[0] = old[1];
new[1] = old[2];
new[2] = old[3] ^ old[4]<<3;
new[3] = old[4];
new[4] = old[5] ^ old[6]>>3;
new[5] = old[6] ^ old[3]>>2;
new[6] = old[7];
new[7] = old[0];
}
static void _multiply_MR2(const uint8_t old[LANE_BYTES], uint8_t new[LANE_BYTES])
{
uint8_t tmp[LANE_BYTES];
memcpy(tmp, old, LANE_BYTES);
_multiply_MR(old, tmp);
_multiply_MR(tmp, new);
}
static void _multiply_MR3(const uint8_t old[LANE_BYTES], uint8_t new[LANE_BYTES])
{
uint8_t tmp[LANE_BYTES];
memcpy(tmp, old, LANE_BYTES);
_multiply_MR2(old, tmp);
_multiply_MR(tmp, new);
}
typedef void (*matrix_multiplication)(const uint8_t old[LANE_BYTES], uint8_t new[LANE_BYTES]);
static const matrix_multiplication ALPHAS[6] = {
_multiply_M,
_multiply_M2,
_multiply_M3,
_multiply_MR,
_multiply_MR2,
_multiply_MR3
};
void tweakey_state_update(uint8_t TK[TWEAKEY_BYTES])
{
/* Skip lane 0, as it is multiplied by the identity matrix. */
for (size_t j=1; j<LANES_NB; j++)
{
uint8_t *TKj = TK + j*LANE_BYTES;
uint8_t TKj_old[LANE_BYTES];
memcpy(TKj_old, TKj, LANE_BYTES);
ALPHAS[j-1](TKj_old, TKj);
}
}
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