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/*
* ChaCha cipher.
*
* Copyright (c) 2014 Marko Kreen
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
/**
* @file
* ChaCha cipher.
*/
#ifndef _CHACHA_CLEAN_H_
#define _CHACHA_CLEAN_H_
#include <usual/base.h>
#define CHACHA_KEY_SIZE 32
#define CHACHA_IV_SIZE 8
#define CHACHA_BLOCK_SIZE 64
/**
* ChaCha state.
*/
struct ChaCha {
uint32_t state[16];
union {
uint32_t output32[16];
uint8_t output8[16*4];
} u;
unsigned int pos;
};
/**
* Set 256-bit key.
*/
void chacha_set_key_256(struct ChaCha *ctx, const void *key);
/**
* Set 128-bit key.
*/
void chacha_set_key_128(struct ChaCha *ctx, const void *key);
/**
* Set 2x32-bit counter and 8-byte IV.
*/
void chacha_set_nonce(struct ChaCha *ctx, uint32_t counter_low, uint32_t counter_high, const void *iv);
/**
* Extract plain keystream.
*/
void chacha_keystream(struct ChaCha *ctx, void *stream, size_t bytes);
/**
* XOR data with keystream.
*/
void chacha_keystream_xor(struct ChaCha *ctx, const void *plain, void *encrypted, size_t bytes);
#endif
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