/* rsa-sec-decrypt.c
RSA decryption, using randomized RSA blinding to be more resistant
to side-channel attacks like timing attacks or cache based memory
access measurements.
Copyright (C) 2001, 2012 Niels MÃ¶ller, Nikos Mavrogiannopoulos
Copyright (C) 2018 Red Hat, Inc.
This file is part of GNU Nettle.
GNU Nettle is free software: you can redistribute it and/or
modify it under the terms of either:
* the GNU Lesser General Public License as published by the Free
Software Foundation; either version 3 of the License, or (at your
option) any later version.
or
* the GNU General Public License as published by the Free
Software Foundation; either version 2 of the License, or (at your
option) any later version.
or both in parallel, as here.
GNU Nettle is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received copies of the GNU General Public License and
the GNU Lesser General Public License along with this program. If
not, see http://www.gnu.org/licenses/.
*/
#if HAVE_CONFIG_H
# include "config.h"
#endif
#include "rsa.h"
#include "pkcs1-internal.h"
#include "rsa-internal.h"
#include "gmp-glue.h"
int
rsa_sec_decrypt(const struct rsa_public_key *pub,
const struct rsa_private_key *key,
void *random_ctx, nettle_random_func *random,
size_t length, uint8_t *message,
const mpz_t gibberish)
{
TMP_GMP_DECL (m, mp_limb_t);
TMP_GMP_DECL (em, uint8_t);
int res;
TMP_GMP_ALLOC (m, mpz_size(pub->n));
TMP_GMP_ALLOC (em, key->size);
res = _rsa_sec_compute_root_tr (pub, key, random_ctx, random, m,
mpz_limbs_read(gibberish),
mpz_size(gibberish));
mpn_get_base256 (em, key->size, m, mpz_size(pub->n));
res &= _pkcs1_sec_decrypt (length, message, key->size, em);
TMP_GMP_FREE (em);
TMP_GMP_FREE (m);
return res;
}