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#include <stddef.h>
#include <stdint.h>
#include <string.h>
#include "crypto_auth_hmacsha256.h"
#include "crypto_hash_sha256.h"
#include "crypto_verify_32.h"
#include "randombytes.h"
#include "utils.h"
size_t
crypto_auth_hmacsha256_bytes(void)
{
return crypto_auth_hmacsha256_BYTES;
}
size_t
crypto_auth_hmacsha256_keybytes(void)
{
return crypto_auth_hmacsha256_KEYBYTES;
}
size_t
crypto_auth_hmacsha256_statebytes(void)
{
return sizeof(crypto_auth_hmacsha256_state);
}
void
crypto_auth_hmacsha256_keygen(unsigned char k[crypto_auth_hmacsha256_KEYBYTES])
{
randombytes_buf(k, crypto_auth_hmacsha256_KEYBYTES);
}
int
crypto_auth_hmacsha256_init(crypto_auth_hmacsha256_state *state,
const unsigned char *key, size_t keylen)
{
unsigned char pad[64];
unsigned char khash[32];
size_t i;
if (keylen > 64) {
crypto_hash_sha256_init(&state->ictx);
crypto_hash_sha256_update(&state->ictx, key, keylen);
crypto_hash_sha256_final(&state->ictx, khash);
key = khash;
keylen = 32;
}
crypto_hash_sha256_init(&state->ictx);
memset(pad, 0x36, 64);
for (i = 0; i < keylen; i++) {
pad[i] ^= key[i];
}
crypto_hash_sha256_update(&state->ictx, pad, 64);
crypto_hash_sha256_init(&state->octx);
memset(pad, 0x5c, 64);
for (i = 0; i < keylen; i++) {
pad[i] ^= key[i];
}
crypto_hash_sha256_update(&state->octx, pad, 64);
sodium_memzero((void *) pad, sizeof pad);
sodium_memzero((void *) khash, sizeof khash);
return 0;
}
int
crypto_auth_hmacsha256_update(crypto_auth_hmacsha256_state *state,
const unsigned char *in, unsigned long long inlen)
{
crypto_hash_sha256_update(&state->ictx, in, inlen);
return 0;
}
int
crypto_auth_hmacsha256_final(crypto_auth_hmacsha256_state *state,
unsigned char *out)
{
unsigned char ihash[32];
crypto_hash_sha256_final(&state->ictx, ihash);
crypto_hash_sha256_update(&state->octx, ihash, 32);
crypto_hash_sha256_final(&state->octx, out);
sodium_memzero((void *) ihash, sizeof ihash);
return 0;
}
int
crypto_auth_hmacsha256(unsigned char *out, const unsigned char *in,
unsigned long long inlen, const unsigned char *k)
{
crypto_auth_hmacsha256_state state;
crypto_auth_hmacsha256_init(&state, k, crypto_auth_hmacsha256_KEYBYTES);
crypto_auth_hmacsha256_update(&state, in, inlen);
crypto_auth_hmacsha256_final(&state, out);
return 0;
}
int
crypto_auth_hmacsha256_verify(const unsigned char *h, const unsigned char *in,
unsigned long long inlen, const unsigned char *k)
{
unsigned char correct[32];
crypto_auth_hmacsha256(correct, in, inlen, k);
return crypto_verify_32(h, correct) | (-(h == correct)) |
sodium_memcmp(correct, h, 32);
}
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