119 lines
3.5 KiB
C
119 lines
3.5 KiB
C
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/*
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This file is part of TALER
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(C) 2014 Christian Grothoff (and other contributing authors)
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TALER is free software; you can redistribute it and/or modify it under the
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terms of the GNU General Public License as published by the Free Software
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Foundation; either version 3, or (at your option) any later version.
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TALER is distributed in the hope that it will be useful, but WITHOUT ANY
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WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
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A PARTICULAR PURPOSE. See the GNU General Public License for more details.
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You should have received a copy of the GNU General Public License along with
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TALER; see the file COPYING. If not, If not, see <http://www.gnu.org/licenses/>
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*/
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/**
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* @file crypto.c
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* @brief Cryptographic utility functions
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* @author Sree Harsha Totakura <sreeharsha@totakura.in>
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* @author Florian Dold
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* @author Benedikt Mueller
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*/
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#include "platform.h"
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#include "taler_util.h"
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#include <gnunet/gnunet_common.h>
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#include <gnunet/gnunet_util_lib.h>
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#include <gcrypt.h>
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#define CURVE "Ed25519"
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static void
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fatal_error_handler (void *cls, int wtf, const char *msg)
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{
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LOG_ERROR("Fatal error in Gcrypt: %s\n", msg);
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abort();
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}
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/**
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* Initialize Gcrypt library.
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*/
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void
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TALER_gcrypt_init()
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{
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gcry_set_fatalerror_handler (&fatal_error_handler, NULL);
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TALER_assert_as(gcry_check_version(NEED_LIBGCRYPT_VERSION),
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"libgcrypt version mismatch");
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/* Disable secure memory. */
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gcry_control (GCRYCTL_DISABLE_SECMEM, 0);
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gcry_control (GCRYCTL_INITIALIZATION_FINISHED, 0);
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}
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/**
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* Derive symmetric key material for refresh operations from
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* a given shared secret.
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*
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* @param secret the shared secret
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* @param[out] iv set to initialization vector
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* @param[out] skey set to session key
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*/
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static void
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derive_refresh_key (const struct GNUNET_HashCode *secret,
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struct GNUNET_CRYPTO_SymmetricInitializationVector *iv,
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struct GNUNET_CRYPTO_SymmetricSessionKey *skey)
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{
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static const char ctx_key[] = "taler-key-skey";
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static const char ctx_iv[] = "taler-key-iv";
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GNUNET_assert (GNUNET_YES ==
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GNUNET_CRYPTO_kdf (skey, sizeof (struct GNUNET_CRYPTO_SymmetricSessionKey),
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ctx_key, strlen (ctx_key),
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secret, sizeof (struct GNUNET_HashCode),
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NULL, 0));
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GNUNET_assert (GNUNET_YES ==
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GNUNET_CRYPTO_kdf (iv, sizeof (struct GNUNET_CRYPTO_SymmetricInitializationVector),
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ctx_iv, strlen (ctx_iv),
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secret, sizeof (struct GNUNET_HashCode),
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NULL, 0));
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}
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int
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TALER_refresh_decrypt (const void *input,
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size_t input_size,
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const struct GNUNET_HashCode *secret,
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void *result)
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{
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struct GNUNET_CRYPTO_SymmetricInitializationVector iv;
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struct GNUNET_CRYPTO_SymmetricSessionKey skey;
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derive_refresh_key (secret, &iv, &skey);
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return GNUNET_CRYPTO_symmetric_decrypt (input, input_size, &skey, &iv, result);
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}
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int
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TALER_refresh_encrypt (const void *input,
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size_t input_size,
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const struct GNUNET_HashCode *secret,
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void *result)
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{
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struct GNUNET_CRYPTO_SymmetricInitializationVector iv;
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struct GNUNET_CRYPTO_SymmetricSessionKey skey;
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derive_refresh_key (secret, &iv, &skey);
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return GNUNET_CRYPTO_symmetric_encrypt (input, input_size, &skey, &iv, result);
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}
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/* end of crypto.c */
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