/* * Copyright 2015-2021 The OpenSSL Project Authors. All Rights Reserved. * * Licensed under the Apache License 2.0 (the "License"). You may not use * this file except in compliance with the License. You can obtain a copy * in the file LICENSE in the source distribution or at * https://www.openssl.org/source/license.html */ #ifndef OSSL_CRYPTO_CHACHA_H #define OSSL_CRYPTO_CHACHA_H # pragma once #include <stddef.h> /* * ChaCha20_ctr32 encrypts |len| bytes from |inp| with the given key and * nonce and writes the result to |out|, which may be equal to |inp|. * The |key| is not 32 bytes of verbatim key material though, but the * said material collected into 8 32-bit elements array in host byte * order. Same approach applies to nonce: the |counter| argument is * pointer to concatenated nonce and counter values collected into 4 * 32-bit elements. This, passing crypto material collected into 32-bit * elements as opposite to passing verbatim byte vectors, is chosen for * efficiency in multi-call scenarios. */ void ChaCha20_ctr32(unsigned char *out, const unsigned char *inp, size_t len, const unsigned int key[8], const unsigned int counter[4]); /* * You can notice that there is no key setup procedure. Because it's * as trivial as collecting bytes into 32-bit elements, it's reckoned * that below macro is sufficient. */ #define CHACHA_U8TOU32(p) ( \ ((unsigned int)(p)[0]) | ((unsigned int)(p)[1]<<8) | \ ((unsigned int)(p)[2]<<16) | ((unsigned int)(p)[3]<<24) ) #define CHACHA_KEY_SIZE 32 #define CHACHA_CTR_SIZE 16 #define CHACHA_BLK_SIZE 64 #endif