/* $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