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pqcrypto/crypto_kem/kyber768/avx2/symmetric-shake.c
2021-03-24 21:02:49 +00:00

61 lines
2.1 KiB
C

#include "fips202.h"
#include "params.h"
#include "symmetric.h"
#include <stddef.h>
#include <stdint.h>
/*************************************************
* Name: PQCLEAN_KYBER768_AVX2_kyber_shake128_absorb
*
* Description: Absorb step of the SHAKE128 specialized for the Kyber context.
*
* Arguments: - xof_state *state: pointer to (uninitialized) output
* Keccak state
* - const uint8_t *seed: pointer to KYBER_SYMBYTES input
* to be absorbed into state
* - uint8_t i additional byte of input
* - uint8_t j additional byte of input
**************************************************/
void PQCLEAN_KYBER768_AVX2_kyber_shake128_absorb(xof_state *state,
const uint8_t seed[KYBER_SYMBYTES],
uint8_t x,
uint8_t y) {
unsigned int i;
uint8_t extseed[KYBER_SYMBYTES + 2];
for (i = 0; i < KYBER_SYMBYTES; i++) {
extseed[i] = seed[i];
}
extseed[i++] = x;
extseed[i] = y;
shake128_absorb(state, extseed, sizeof(extseed));
}
/*************************************************
* Name: PQCLEAN_KYBER768_AVX2_kyber_shake256_prf
*
* Description: Usage of SHAKE256 as a PRF, concatenates secret and public input
* and then generates outlen bytes of SHAKE256 output
*
* Arguments: - uint8_t *out: pointer to output
* - size_t outlen: number of requested output bytes
* - const uint8_t *key: pointer to the key
* (of length KYBER_SYMBYTES)
* - uint8_t nonce: single-byte nonce (public PRF input)
**************************************************/
void PQCLEAN_KYBER768_AVX2_kyber_shake256_prf(uint8_t *out,
size_t outlen,
const uint8_t key[KYBER_SYMBYTES],
uint8_t nonce) {
unsigned int i;
uint8_t extkey[KYBER_SYMBYTES + 1];
for (i = 0; i < KYBER_SYMBYTES; i++) {
extkey[i] = key[i];
}
extkey[i] = nonce;
shake256(out, outlen, extkey, sizeof(extkey));
}