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1 | /* |
2 | * Copyright 2015-2016 The OpenSSL Project Authors. All Rights Reserved. | |
7dcb2186 | 3 | * |
aa6bb135 RS |
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 | |
7dcb2186 AP |
8 | */ |
9 | ||
10 | #ifndef HEADER_CHACHA_H | |
11 | #define HEADER_CHACHA_H | |
12 | ||
13 | #include <stddef.h> | |
14 | ||
15 | #ifdef __cplusplus | |
16 | extern "C" { | |
17 | #endif | |
18 | ||
19 | /* | |
20 | * ChaCha20_ctr32 encrypts |len| bytes from |inp| with the given key and | |
21 | * nonce and writes the result to |out|, which may be equal to |inp|. | |
22 | * The |key| is not 32 bytes of verbatim key material though, but the | |
23 | * said material collected into 8 32-bit elements array in host byte | |
24 | * order. Same approach applies to nonce: the |counter| argument is | |
25 | * pointer to concatenated nonce and counter values collected into 4 | |
26 | * 32-bit elements. This, passing crypto material collected into 32-bit | |
27 | * elements as opposite to passing verbatim byte vectors, is chosen for | |
28 | * efficiency in multi-call scenarios. | |
29 | */ | |
30 | void ChaCha20_ctr32(unsigned char *out, const unsigned char *inp, | |
31 | size_t len, const unsigned int key[8], | |
32 | const unsigned int counter[4]); | |
33 | /* | |
34 | * You can notice that there is no key setup procedure. Because it's | |
35 | * as trivial as collecting bytes into 32-bit elements, it's reckoned | |
36 | * that below macro is sufficient. | |
37 | */ | |
38 | #define CHACHA_U8TOU32(p) ( \ | |
39 | ((unsigned int)(p)[0]) | ((unsigned int)(p)[1]<<8) | \ | |
40 | ((unsigned int)(p)[2]<<16) | ((unsigned int)(p)[3]<<24) ) | |
41 | ||
42 | #define CHACHA_KEY_SIZE 32 | |
43 | #define CHACHA_CTR_SIZE 16 | |
44 | #define CHACHA_BLK_SIZE 64 | |
45 | ||
46 | #ifdef __cplusplus | |
47 | } | |
48 | #endif | |
49 | #endif |