/*
   This file is part of GNUnet
   Copyright (C) 2014,2015 GNUnet e.V.

   GNUnet is free software: you can redistribute it and/or modify it
   under the terms of the GNU Affero General Public License as published
   by the Free Software Foundation, either version 3 of the License,
   or (at your option) any later version.

   GNUnet 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
   Affero General Public License for more details.

   You should have received a copy of the GNU Affero General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.

     SPDX-License-Identifier: AGPL3.0-or-later
 */

/**
 * @file util/test_crypto_rsa.c
 * @brief testcase for utility functions for RSA cryptography
 * @author Sree Harsha Totakura <sreeharsha@totakura.in>
 * @author Jeffrey Burdges <burdges@gnunet.org>
 */
#include "platform.h"
#include <gcrypt.h>
#include "gnunet_util_lib.h"

#define KEY_SIZE 1024


int
main(int argc,
     char *argv[])
{
#define RND_BLK_SIZE 4096
  unsigned char rnd_blk[RND_BLK_SIZE];
  struct GNUNET_CRYPTO_RsaPrivateKey *priv;
  struct GNUNET_CRYPTO_RsaPrivateKey *priv_copy;
  struct GNUNET_CRYPTO_RsaPublicKey *pub;
  struct GNUNET_CRYPTO_RsaPublicKey *pub_copy;
  struct GNUNET_CRYPTO_RsaSignature *sig;
  struct GNUNET_CRYPTO_RsaSignature *sig_copy;
  struct GNUNET_CRYPTO_RsaSignature *bsig;
  struct GNUNET_CRYPTO_RsaBlindingKeySecret bsec;
  struct GNUNET_HashCode hash;
  char *blind_buf;
  size_t bsize;

  GNUNET_log_setup("test-rsa", "WARNING", NULL);
  GNUNET_CRYPTO_random_block(GNUNET_CRYPTO_QUALITY_WEAK,
                             rnd_blk,
                             RND_BLK_SIZE);
  GNUNET_CRYPTO_hash(rnd_blk,
                     RND_BLK_SIZE,
                     &hash);
  priv = GNUNET_CRYPTO_rsa_private_key_create(KEY_SIZE);
  priv_copy = GNUNET_CRYPTO_rsa_private_key_dup(priv);
  GNUNET_assert(NULL != priv_copy);
  GNUNET_assert(0 == GNUNET_CRYPTO_rsa_private_key_cmp(priv, priv_copy));
  pub = GNUNET_CRYPTO_rsa_private_key_get_public(priv);

  /* Encoding */
  size_t size;
  char *enc;
  enc = NULL;
  size = GNUNET_CRYPTO_rsa_private_key_encode(priv, &enc);

  /* Decoding */
  GNUNET_CRYPTO_rsa_private_key_free(priv);
  priv = NULL;
  priv = GNUNET_CRYPTO_rsa_private_key_decode(enc, size);
  GNUNET_assert(NULL != priv);
  GNUNET_CRYPTO_random_block(GNUNET_CRYPTO_QUALITY_WEAK,
                             enc, size);
  GNUNET_assert(NULL == GNUNET_CRYPTO_rsa_private_key_decode(enc, size));
  (void)fprintf(stderr, "The above warning is expected.\n");
  GNUNET_free(enc);

  /* try ordinary sig first */
  sig = GNUNET_CRYPTO_rsa_sign_fdh(priv,
                                   &hash);
  sig_copy = GNUNET_CRYPTO_rsa_signature_dup(sig);
  GNUNET_assert(NULL != sig);
  GNUNET_assert(0 == GNUNET_CRYPTO_rsa_signature_cmp(sig, sig_copy));
  pub_copy = GNUNET_CRYPTO_rsa_public_key_dup(pub);
  GNUNET_assert(NULL != pub_copy);
  GNUNET_assert(GNUNET_OK ==
                GNUNET_CRYPTO_rsa_verify(&hash, sig, pub_copy));
  /* corrupt our hash and see if the signature is still valid */
  GNUNET_CRYPTO_random_block(GNUNET_CRYPTO_QUALITY_WEAK, &hash,
                             sizeof(struct GNUNET_HashCode));
  GNUNET_assert(GNUNET_OK != GNUNET_CRYPTO_rsa_verify(&hash,
                                                      sig,
                                                      pub));
  (void)fprintf(stderr, "The above warning is expected.\n");
  GNUNET_CRYPTO_rsa_signature_free(sig);

  /* test blind signing */
  GNUNET_CRYPTO_random_block(GNUNET_CRYPTO_QUALITY_WEAK,
                             &bsec,
                             sizeof(bsec));
  GNUNET_CRYPTO_rsa_blind(&hash,
                          &bsec,
                          pub,
                          &blind_buf, &bsize);
  GNUNET_assert(0 != bsize);
  bsig = GNUNET_CRYPTO_rsa_sign_blinded(priv,
                                        blind_buf,
                                        bsize);
  GNUNET_free(blind_buf);
  sig = GNUNET_CRYPTO_rsa_unblind(bsig,
                                  &bsec,
                                  pub);
  GNUNET_CRYPTO_rsa_signature_free(bsig);
  GNUNET_assert(GNUNET_OK ==
                GNUNET_CRYPTO_rsa_verify(&hash, sig, pub));
  GNUNET_CRYPTO_rsa_signature_free(sig);
  GNUNET_CRYPTO_rsa_signature_free(sig_copy);
  GNUNET_CRYPTO_rsa_private_key_free(priv);
  GNUNET_CRYPTO_rsa_private_key_free(priv_copy);
  GNUNET_CRYPTO_rsa_public_key_free(pub);
  GNUNET_CRYPTO_rsa_public_key_free(pub_copy);
  return 0;
}