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/*
This file is part of GNUnet.
Copyright (C) 2012, 2013, 2019 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/crypto_pow.c
* @brief proof-of-work hashing
* @author Christian Grothoff
* @author Bart Polot
*/
#include "platform.h"
#include "gnunet_crypto_lib.h"
#include <argon2.h>
#define LSD001
/**
* Calculate the 'proof-of-work' hash (an expensive hash).
* We're using a non-standard formula to avoid issues with
* ASICs appearing (see #3795).
*
* @param salt salt for the hash
* @param buf data to hash
* @param buf_len number of bytes in @a buf
* @param result where to write the resulting hash
*/
void
GNUNET_CRYPTO_pow_hash (const char *salt,
const void *buf,
size_t buf_len,
struct GNUNET_HashCode *result)
{
#ifdef LSD001
char twofish_iv[128 / 8]; // 128 bit IV
char twofish_key[256 / 8]; // 256 bit Key
char rbuf[buf_len];
int rc;
gcry_cipher_hd_t handle;
GNUNET_break (ARGON2_OK == argon2d_hash_raw (2, /* iterations */
100000, /* memory (kb) */
1, /* threads */
buf,
buf_len,
salt,
strlen (salt),
&twofish_key,
sizeof (twofish_key)));
GNUNET_CRYPTO_kdf (twofish_iv,
sizeof (twofish_iv),
"gnunet-proof-of-work-iv",
strlen ("gnunet-proof-of-work-iv"),
twofish_key,
sizeof(twofish_key),
salt,
strlen (salt),
NULL, 0);
GNUNET_assert (0 ==
gcry_cipher_open (&handle, GCRY_CIPHER_TWOFISH,
GCRY_CIPHER_MODE_CFB, 0));
rc = gcry_cipher_setkey (handle,
twofish_key,
sizeof(twofish_key));
GNUNET_assert ((0 == rc) || ((char) rc == GPG_ERR_WEAK_KEY));
rc = gcry_cipher_setiv (handle,
twofish_iv,
sizeof(twofish_iv));
GNUNET_assert ((0 == rc) || ((char) rc == GPG_ERR_WEAK_KEY));
GNUNET_assert (0 == gcry_cipher_encrypt (handle, &rbuf, buf_len, buf,
buf_len));
gcry_cipher_close (handle);
GNUNET_break (ARGON2_OK == argon2d_hash_raw (2, /* iterations */
100000, /* memory */
1, /* threads */
rbuf,
buf_len,
salt,
strlen (salt),
result,
sizeof (struct GNUNET_HashCode)));
#else
struct GNUNET_CRYPTO_SymmetricInitializationVector iv;
struct GNUNET_CRYPTO_SymmetricSessionKey skey;
char rbuf[buf_len];
GNUNET_break (ARGON2_OK == argon2d_hash_raw (buf,
buf_len,
GCRY_KDF_SCRYPT,
1 /* subalgo */,
salt,
strlen (salt),
2 /* iterations; keep cost of individual op small */,
sizeof(skey),
&skey));
GNUNET_CRYPTO_symmetric_derive_iv (&iv,
&skey,
"gnunet-proof-of-work-iv",
strlen ("gnunet-proof-of-work-iv"),
salt,
strlen (salt),
NULL, 0);
GNUNET_CRYPTO_symmetric_encrypt (buf,
buf_len,
&skey,
&iv,
&rbuf);
GNUNET_break (0 == gcry_kdf_derive (rbuf,
buf_len,
GCRY_KDF_SCRYPT,
1 /* subalgo */,
salt,
strlen (salt),
2 /* iterations; keep cost of individual op small */,
sizeof(struct GNUNET_HashCode),
result));
#endif
}
/* end of crypto_pow.c */
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