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/* $OpenBSD: arc4random.c,v 1.54 2015/09/13 08:31:47 guenther Exp $ */
/*
* Copyright (c) 1996, David Mazieres <dm@uun.org>
* Copyright (c) 2008, Damien Miller <djm@openbsd.org>
* Copyright (c) 2013, Markus Friedl <markus@openbsd.org>
* Copyright (c) 2014, Theo de Raadt <deraadt@openbsd.org>
*
* Permission to use, copy, modify, and 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.
*/
/*
* ChaCha based random number generator for OpenBSD.
*/
/*
* Adapted for VeraCrypt
*/
#ifndef HEADER_Crypto_ChaChaRng
#define HEADER_Crypto_ChaChaRng
#include "chacha256.h"
#define CHACHA20RNG_KEYSZ 32
#define CHACHA20RNG_IVSZ 8
#define CHACHA20RNG_BLOCKSZ 64
#define CHACHA20RNG_RSBUFSZ (16*CHACHA20RNG_BLOCKSZ)
#ifdef __cplusplus
extern "C" {
#endif
typedef void (*GetRandSeedFn)(unsigned char* pbRandSeed, size_t cbRandSeed);
typedef struct
{
ChaCha256Ctx m_chachaCtx; /* ChaCha20 context */
unsigned char m_rs_buf[CHACHA20RNG_RSBUFSZ]; /* keystream blocks */
size_t m_rs_have; /* valid bytes at end of rs_buf */
size_t m_rs_count; /* bytes till reseed */
GetRandSeedFn m_getRandSeedCallback;
} ChaCha20RngCtx;
/* key length must be equal to 40 bytes (CHACHA20RNG_KEYSZ + CHACHA20RNG_IVSZ) */
void ChaCha20RngInit (ChaCha20RngCtx* pCtx, const unsigned char* key, GetRandSeedFn rngCallback, size_t InitialBytesToSkip);
void ChaCha20RngGetBytes (ChaCha20RngCtx* pCtx, unsigned char* buffer, size_t bufferLen);
#ifdef __cplusplus
}
#endif
#endif
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