FFmpeg/libavutil/des.h
David Goldwich b3e144a7df des: add possibility to calculate DES-CBC-MAC with small buffer
This patch adds the possibility to calculate the DES-CBC-MAC of a
source buffer (i.e. the last block of the buffer encrypted in CBC
mode) without having to allocate a destination buffer that is as
long as the complete source buffer, but instead only 8 bytes
for the MAC.

Signed-off-by: David Goldwich <david.goldwich@gmail.com>
Signed-off-by: Anton Khirnov <anton@khirnov.net>
2011-09-21 08:28:20 +02:00

62 lines
2.1 KiB
C

/*
* DES encryption/decryption
* Copyright (c) 2007 Reimar Doeffinger
*
* This file is part of Libav.
*
* Libav is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* Libav 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with Libav; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#ifndef AVUTIL_DES_H
#define AVUTIL_DES_H
#include <stdint.h>
struct AVDES {
uint64_t round_keys[3][16];
int triple_des;
};
/**
* @brief Initializes an AVDES context.
*
* @param key_bits must be 64 or 192
* @param decrypt 0 for encryption/CBC-MAC, 1 for decryption
*/
int av_des_init(struct AVDES *d, const uint8_t *key, int key_bits, int decrypt);
/**
* @brief Encrypts / decrypts using the DES algorithm.
*
* @param count number of 8 byte blocks
* @param dst destination array, can be equal to src, must be 8-byte aligned
* @param src source array, can be equal to dst, must be 8-byte aligned, may be NULL
* @param iv initialization vector for CBC mode, if NULL then ECB will be used,
* must be 8-byte aligned
* @param decrypt 0 for encryption, 1 for decryption
*/
void av_des_crypt(struct AVDES *d, uint8_t *dst, const uint8_t *src, int count, uint8_t *iv, int decrypt);
/**
* @brief Calculates CBC-MAC using the DES algorithm.
*
* @param count number of 8 byte blocks
* @param dst destination array, can be equal to src, must be 8-byte aligned
* @param src source array, can be equal to dst, must be 8-byte aligned, may be NULL
*/
void av_des_mac(struct AVDES *d, uint8_t *dst, const uint8_t *src, int count);
#endif /* AVUTIL_DES_H */