2d798bc4cf
This adds an internal implementation of the AES-SIV-CMAC-256 cipher based on GNU Nettle and the following patch (which was later reworked and included in Nettle): https://gitlab.com/gnutls/gnutls/uploads/1ab02c51e317264f9dba07ddfbc01d9a/0001-Added-support-for-AES_SIV_CMAC_256-and-AES_SIV_CMAC_.patch This implementation will be dropped when the cipher is widely supported by gnutls or Nettle.
142 lines
3.8 KiB
C
142 lines
3.8 KiB
C
/*
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chronyd/chronyc - Programs for keeping computer clocks accurate.
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**********************************************************************
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* Copyright (C) Miroslav Lichvar 2019
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of version 2 of the GNU General Public License as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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*
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**********************************************************************
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=======================================================================
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SIV ciphers using the Nettle library
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*/
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#include "config.h"
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#include "sysincl.h"
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#ifdef HAVE_NETTLE_SIV_CMAC
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#include <nettle/siv-cmac.h>
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#else
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#include "siv_nettle_int.c"
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#endif
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#include "memory.h"
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#include "siv.h"
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struct SIV_Instance_Record {
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struct siv_cmac_aes128_ctx siv;
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};
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/* ================================================== */
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SIV_Instance
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SIV_CreateInstance(SIV_Algorithm algorithm)
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{
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SIV_Instance instance;
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if (algorithm != AEAD_AES_SIV_CMAC_256)
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return NULL;
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instance = MallocNew(struct SIV_Instance_Record);
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return instance;
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}
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/* ================================================== */
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void
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SIV_DestroyInstance(SIV_Instance instance)
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{
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Free(instance);
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}
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/* ================================================== */
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int
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SIV_GetKeyLength(SIV_Algorithm algorithm)
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{
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if (algorithm == AEAD_AES_SIV_CMAC_256)
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return 32;
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return 0;
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}
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/* ================================================== */
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int
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SIV_SetKey(SIV_Instance instance, const unsigned char *key, int length)
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{
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if (length != 32)
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return 0;
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siv_cmac_aes128_set_key(&instance->siv, key);
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return 1;
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}
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/* ================================================== */
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int
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SIV_GetTagLength(SIV_Instance instance)
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{
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return SIV_DIGEST_SIZE;
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}
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/* ================================================== */
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int
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SIV_Encrypt(SIV_Instance instance,
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const unsigned char *nonce, int nonce_length,
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const void *assoc, int assoc_length,
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const void *plaintext, int plaintext_length,
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unsigned char *ciphertext, int ciphertext_length)
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{
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if (nonce_length < SIV_MIN_NONCE_SIZE || assoc_length < 0 ||
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plaintext_length < 0 || plaintext_length > ciphertext_length ||
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plaintext_length + SIV_DIGEST_SIZE != ciphertext_length)
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return 0;
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assert(assoc && plaintext);
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siv_cmac_aes128_encrypt_message(&instance->siv, nonce_length, nonce,
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assoc_length, assoc,
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ciphertext_length, ciphertext, plaintext);
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return 1;
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}
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/* ================================================== */
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int
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SIV_Decrypt(SIV_Instance instance,
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const unsigned char *nonce, int nonce_length,
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const void *assoc, int assoc_length,
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const unsigned char *ciphertext, int ciphertext_length,
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void *plaintext, int plaintext_length)
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{
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if (nonce_length < SIV_MIN_NONCE_SIZE || assoc_length < 0 ||
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plaintext_length < 0 || plaintext_length > ciphertext_length ||
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plaintext_length + SIV_DIGEST_SIZE != ciphertext_length)
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return 0;
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assert(assoc && plaintext);
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if (!siv_cmac_aes128_decrypt_message(&instance->siv, nonce_length, nonce,
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assoc_length, assoc,
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plaintext_length, plaintext, ciphertext))
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return 0;
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return 1;
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}
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