chacha.h

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/*
 * Copyright (C) 2008  D. J. Bernstein  (dedicated to the public domain)
 * Copyright (C) 2015  René Kijewski  <rene.kijewski@fu-berlin.de>
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */
 
#pragma once

 
#include <stdint.h>
#include <stddef.h>
 
#ifdef __cplusplus
extern "C" {
#endif

typedef struct {
    uint32_t state[16]; 
    uint8_t rounds;     
} chacha_ctx;

int chacha_init(chacha_ctx *ctx,
                unsigned rounds,
                const uint8_t *key, uint32_t keylen,
                const uint8_t nonce[8]);

void chacha_keystream_bytes(chacha_ctx *ctx, void *x);

void chacha_encrypt_bytes(chacha_ctx *ctx, const uint8_t *m, uint8_t *c);

static inline void chacha_decrypt_bytes(chacha_ctx *ctx, const uint8_t *m,
                                        uint8_t *c)
{
    chacha_encrypt_bytes(ctx, m, c);
}

void chacha_prng_seed(const void *data, size_t bytes);

uint32_t chacha_prng_next(void);
 
#ifdef __cplusplus
}
#endif