/**
Terminate the PRNG
@param prng The PRNG to terminate
@return CRYPT_OK if successful
*/
int chacha20_prng_done(prng_state *prng)
{
int err;
LTC_ARGCHK(prng != NULL);
LTC_MUTEX_LOCK(&prng->lock);
prng->ready = 0;
err = chacha_done(&prng->chacha.s);
LTC_MUTEX_UNLOCK(&prng->lock);
LTC_MUTEX_DESTROY(&prng->lock);
return err;
}
/**
Terminate a ChaCha20Poly1305 stream
@param st The ChaCha20Poly1305 state
@param tag [out] The destination for the MAC tag
@param taglen [in/out] The length of the MAC tag
@return CRYPT_OK on success
*/
int chacha20poly1305_done(chacha20poly1305_state *st, unsigned char *tag, unsigned long *taglen)
{
unsigned char padzero[16] = { 0 };
unsigned long padlen;
unsigned char buf[16];
int err;
LTC_ARGCHK(st != NULL);
padlen = 16 - (unsigned long)(st->ctlen % 16);
if (padlen < 16) {
if ((err = poly1305_process(&st->poly, padzero, padlen)) != CRYPT_OK) return err;
}
STORE64L(st->aadlen, buf);
STORE64L(st->ctlen, buf + 8);
if ((err = poly1305_process(&st->poly, buf, 16)) != CRYPT_OK) return err;
if ((err = poly1305_done(&st->poly, tag, taglen)) != CRYPT_OK) return err;
if ((err = chacha_done(&st->chacha)) != CRYPT_OK) return err;
return CRYPT_OK;
}