pqc/crypto_sign/rainbowIa-cyclic/clean/utils_hash.c

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2019-06-18 10:28:41 +01:00
/// @file utils_hash.c
/// @brief the adapter for SHA2 families.
///
///
#include "rainbow_config.h"
#include "sha2.h"
#include "utils_hash.h"
static inline
int _hash( unsigned char *digest, const unsigned char *m, size_t mlen ) {
#if 32 == _HASH_LEN
sha256(digest, m, mlen);
#elif 48 == _HASH_LEN
sha384(digest, m, mlen);
#elif 64 == _HASH_LEN
sha512(digest, m, mlen);
#else
#error "unsupported _HASH_LEN"
#endif
return 0;
}
static inline
int expand_hash(unsigned char *digest, size_t n_digest, const unsigned char *hash) {
if ( _HASH_LEN >= n_digest ) {
for (size_t i = 0; i < n_digest; i++) {
digest[i] = hash[i];
}
return 0;
}
for (size_t i = 0; i < _HASH_LEN; i++) {
digest[i] = hash[i];
}
n_digest -= _HASH_LEN;
while (_HASH_LEN <= n_digest ) {
_hash( digest + _HASH_LEN, digest, _HASH_LEN );
n_digest -= _HASH_LEN;
digest += _HASH_LEN;
}
unsigned char temp[_HASH_LEN];
if ( n_digest ) {
_hash( temp, digest, _HASH_LEN );
for (size_t i = 0; i < n_digest; i++) {
digest[_HASH_LEN + i] = temp[i];
}
}
return 0;
}
int PQCLEAN_RAINBOWIACYCLIC_CLEAN_hash_msg(unsigned char *digest,
size_t len_digest,
const unsigned char *m,
size_t mlen) {
unsigned char buf[_HASH_LEN];
_hash(buf, m, mlen);
return expand_hash(digest, len_digest, buf);
}