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/*
chronyd/chronyc - Programs for keeping computer clocks accurate.
**********************************************************************
* Copyright (C) Miroslav Lichvar 2019
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of version 2 of the GNU General Public License as
* published by the Free Software Foundation.
*
* This program 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 a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*
**********************************************************************
=======================================================================
SIV ciphers using the Nettle library
*/
#include "config.h"
#include "sysincl.h"
#ifdef HAVE_NETTLE_SIV_CMAC
#include <nettle/siv-cmac.h>
#else
#include "siv_nettle_int.c"
#endif
#include "memory.h"
#include "siv.h"
struct SIV_Instance_Record {
struct siv_cmac_aes128_ctx siv;
int key_set;
};
/* ================================================== */
SIV_Instance
SIV_CreateInstance(SIV_Algorithm algorithm)
{
SIV_Instance instance;
if (algorithm != AEAD_AES_SIV_CMAC_256)
return NULL;
instance = MallocNew(struct SIV_Instance_Record);
instance->key_set = 0;
return instance;
}
/* ================================================== */
void
SIV_DestroyInstance(SIV_Instance instance)
{
Free(instance);
}
/* ================================================== */
int
SIV_GetKeyLength(SIV_Algorithm algorithm)
{
assert(32 <= SIV_MAX_KEY_LENGTH);
if (algorithm == AEAD_AES_SIV_CMAC_256)
return 32;
return 0;
}
/* ================================================== */
int
SIV_SetKey(SIV_Instance instance, const unsigned char *key, int length)
{
if (length != 32)
return 0;
siv_cmac_aes128_set_key(&instance->siv, key);
instance->key_set = 1;
return 1;
}
/* ================================================== */
int
SIV_GetTagLength(SIV_Instance instance)
{
assert(SIV_DIGEST_SIZE <= SIV_MAX_TAG_LENGTH);
return SIV_DIGEST_SIZE;
}
/* ================================================== */
int
SIV_Encrypt(SIV_Instance instance,
const unsigned char *nonce, int nonce_length,
const void *assoc, int assoc_length,
const void *plaintext, int plaintext_length,
unsigned char *ciphertext, int ciphertext_length)
{
if (!instance->key_set)
return 0;
if (nonce_length < SIV_MIN_NONCE_SIZE || assoc_length < 0 ||
plaintext_length < 0 || plaintext_length > ciphertext_length ||
plaintext_length + SIV_DIGEST_SIZE != ciphertext_length)
return 0;
assert(assoc && plaintext);
siv_cmac_aes128_encrypt_message(&instance->siv, nonce_length, nonce,
assoc_length, assoc,
ciphertext_length, ciphertext, plaintext);
return 1;
}
/* ================================================== */
int
SIV_Decrypt(SIV_Instance instance,
const unsigned char *nonce, int nonce_length,
const void *assoc, int assoc_length,
const unsigned char *ciphertext, int ciphertext_length,
void *plaintext, int plaintext_length)
{
if (!instance->key_set)
return 0;
if (nonce_length < SIV_MIN_NONCE_SIZE || assoc_length < 0 ||
plaintext_length < 0 || plaintext_length > ciphertext_length ||
plaintext_length + SIV_DIGEST_SIZE != ciphertext_length)
return 0;
assert(assoc && plaintext);
if (!siv_cmac_aes128_decrypt_message(&instance->siv, nonce_length, nonce,
assoc_length, assoc,
plaintext_length, plaintext, ciphertext))
return 0;
return 1;
}
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