| /* |
| * Copyright 2015-2018 The OpenSSL Project Authors. All Rights Reserved. |
| * |
| * Licensed under the OpenSSL license (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 |
| |
| #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 |