65 lines
2.7 KiB
C
65 lines
2.7 KiB
C
#include "fips202.h"
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#include "symmetric.h"
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#include <stdlib.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: - shake128ctx *s: pointer to (uninitialized) output Keccak state
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* - const unsigned char *input: pointer to KYBER_SYMBYTES input to be absorbed into s
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* - unsigned char i additional byte of input
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* - unsigned char j additional byte of input
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**************************************************/
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void PQCLEAN_KYBER768_CLEAN_kyber_shake128_absorb(shake128ctx *s, const unsigned char *input, unsigned char x, unsigned char y) {
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unsigned char extseed[KYBER_SYMBYTES + 2];
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int i;
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for (i = 0; i < KYBER_SYMBYTES; i++) {
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extseed[i] = input[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(s, extseed, KYBER_SYMBYTES + 2);
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}
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/*************************************************
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* Name: PQCLEAN_KYBER768_CLEAN_kyber_shake128_squeezeblocks
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*
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* Description: Squeeze step of SHAKE128 XOF. Squeezes full blocks of SHAKE128_RATE bytes each.
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* Modifies the state. Can be called multiple times to keep squeezing,
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* i.e., is incremental.
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*
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* Arguments: - unsigned char *output: pointer to output blocks
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* - size_t nblocks: number of blocks to be squeezed (written to output)
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* - shake128ctx *s: pointer to in/output Keccak state
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**************************************************/
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void PQCLEAN_KYBER768_CLEAN_kyber_shake128_squeezeblocks(unsigned char *output, size_t nblocks, shake128ctx *s) {
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shake128_squeezeblocks(output, nblocks, s);
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}
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/*************************************************
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* Name: PQCLEAN_KYBER768_CLEAN_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: - unsigned char *output: pointer to output
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* - size_t outlen: number of requested output bytes
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* - const unsigned char * key: pointer to the key (of length KYBER_SYMBYTES)
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* - const unsigned char nonce: single-byte nonce (public PRF input)
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**************************************************/
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void PQCLEAN_KYBER768_CLEAN_shake256_prf(unsigned char *output, size_t outlen, const unsigned char *key, unsigned char nonce) {
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unsigned char extkey[KYBER_SYMBYTES + 1];
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size_t i;
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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(output, outlen, extkey, KYBER_SYMBYTES + 1);
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}
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