1 /* 2 * Copyright 2015-2018 The OpenSSL Project Authors. All Rights Reserved. 3 * 4 * Licensed under the OpenSSL license (the "License"). You may not use 5 * this file except in compliance with the License. You can obtain a copy 6 * in the file LICENSE in the source distribution or at 7 * https://www.openssl.org/source/license.html 8 */ 9 10 /* From include/crypto/chacha.h */ 11 12 #ifndef OSSL_CRYPTO_CHACHA_H 13 #define OSSL_CRYPTO_CHACHA_H 14 15 /* 16 * ChaCha20_ctr32 encrypts |len| bytes from |inp| with the given key and 17 * nonce and writes the result to |out|, which may be equal to |inp|. 18 * The |key| is not 32 bytes of verbatim key material though, but the 19 * said material collected into 8 32-bit elements array in host byte 20 * order. Same approach applies to nonce: the |counter| argument is 21 * pointer to concatenated nonce and counter values collected into 4 22 * 32-bit elements. This, passing crypto material collected into 32-bit 23 * elements as opposite to passing verbatim byte vectors, is chosen for 24 * efficiency in multi-call scenarios. 25 */ 26 void ChaCha20_ctr32(unsigned char *out, const unsigned char *inp, 27 size_t len, const unsigned int key[8], 28 const unsigned int counter[4]); 29 /* 30 * You can notice that there is no key setup procedure. Because it's 31 * as trivial as collecting bytes into 32-bit elements, it's reckoned 32 * that below macro is sufficient. 33 */ 34 #define CHACHA_U8TOU32(p) ( \ 35 ((unsigned int)(p)[0]) | ((unsigned int)(p)[1]<<8) | \ 36 ((unsigned int)(p)[2]<<16) | ((unsigned int)(p)[3]<<24) ) 37 38 #define CHACHA_KEY_SIZE 32 39 #define CHACHA_CTR_SIZE 16 40 #define CHACHA_BLK_SIZE 64 41 42 #endif 43