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- /*
- * 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
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