61 lines
2.1 KiB
C
61 lines
2.1 KiB
C
#include "fips202.h"
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#include "params.h"
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#include "symmetric.h"
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#include <stddef.h>
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#include <stdint.h>
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/*************************************************
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* Name: PQCLEAN_KYBER768_CLEAN_kyber_shake128_absorb
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*
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* Description: Absorb step of the SHAKE128 specialized for the Kyber context.
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*
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* Arguments: - keccak_state *state: pointer to (uninitialized) output
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* Keccak state
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* - const uint8_t *seed: pointer to KYBER_SYMBYTES input
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* to be absorbed into state
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* - uint8_t i additional byte of input
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* - uint8_t j additional byte of input
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**************************************************/
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void PQCLEAN_KYBER768_CLEAN_kyber_shake128_absorb(xof_state *state,
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const uint8_t seed[KYBER_SYMBYTES],
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uint8_t x,
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uint8_t y) {
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unsigned int i = 0;
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uint8_t extseed[KYBER_SYMBYTES + 2];
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for (i = 0; i < KYBER_SYMBYTES; i++) {
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extseed[i] = seed[i];
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}
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extseed[i++] = x;
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extseed[i] = y;
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shake128_absorb(state, extseed, sizeof(extseed));
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}
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/*************************************************
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* Name: PQCLEAN_KYBER768_CLEAN_kyber_shake256_prf
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*
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* Description: Usage of SHAKE256 as a PRF, concatenates secret and public input
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* and then generates outlen bytes of SHAKE256 output
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*
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* Arguments: - uint8_t *out: pointer to output
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* - size_t outlen: number of requested output bytes
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* - const uint8_t *key: pointer to the key
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* (of length KYBER_SYMBYTES)
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* - uint8_t nonce: single-byte nonce (public PRF input)
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**************************************************/
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void PQCLEAN_KYBER768_CLEAN_kyber_shake256_prf(uint8_t *out,
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size_t outlen,
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const uint8_t key[KYBER_SYMBYTES],
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uint8_t nonce) {
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unsigned int i = 0;
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uint8_t extkey[KYBER_SYMBYTES + 1];
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for (i = 0; i < KYBER_SYMBYTES; i++) {
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extkey[i] = key[i];
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}
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extkey[i] = nonce;
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shake256(out, outlen, extkey, sizeof(extkey));
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}
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