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aa6bb135 | 1 | /* |
a28d06f3 | 2 | * Copyright 2015-2021 The OpenSSL Project Authors. All Rights Reserved. |
7dcb2186 | 3 | * |
48f4ad77 | 4 | * Licensed under the Apache License 2.0 (the "License"). You may not use |
aa6bb135 RS |
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 | ||
ae4186b0 DMSP |
10 | #ifndef OSSL_CRYPTO_CHACHA_H |
11 | #define OSSL_CRYPTO_CHACHA_H | |
80ce21fe | 12 | # pragma once |
7dcb2186 AP |
13 | |
14 | #include <stddef.h> | |
15 | ||
7dcb2186 AP |
16 | /* |
17 | * ChaCha20_ctr32 encrypts |len| bytes from |inp| with the given key and | |
18 | * nonce and writes the result to |out|, which may be equal to |inp|. | |
19 | * The |key| is not 32 bytes of verbatim key material though, but the | |
20 | * said material collected into 8 32-bit elements array in host byte | |
21 | * order. Same approach applies to nonce: the |counter| argument is | |
22 | * pointer to concatenated nonce and counter values collected into 4 | |
23 | * 32-bit elements. This, passing crypto material collected into 32-bit | |
24 | * elements as opposite to passing verbatim byte vectors, is chosen for | |
25 | * efficiency in multi-call scenarios. | |
26 | */ | |
27 | void ChaCha20_ctr32(unsigned char *out, const unsigned char *inp, | |
28 | size_t len, const unsigned int key[8], | |
29 | const unsigned int counter[4]); | |
fcf68127 JS |
30 | #ifdef INCLUDE_C_CHACHA20 |
31 | /* The fallback implementation for `ChaCha20_ctr32`. */ | |
32 | void ChaCha20_ctr32_c(unsigned char *out, const unsigned char *inp, size_t len, | |
33 | const unsigned int key[8], const unsigned int counter[4]); | |
34 | #endif | |
35 | ||
7dcb2186 AP |
36 | /* |
37 | * You can notice that there is no key setup procedure. Because it's | |
38 | * as trivial as collecting bytes into 32-bit elements, it's reckoned | |
39 | * that below macro is sufficient. | |
40 | */ | |
41 | #define CHACHA_U8TOU32(p) ( \ | |
42 | ((unsigned int)(p)[0]) | ((unsigned int)(p)[1]<<8) | \ | |
43 | ((unsigned int)(p)[2]<<16) | ((unsigned int)(p)[3]<<24) ) | |
44 | ||
dd6b2706 P |
45 | #define CHACHA_KEY_SIZE 32 |
46 | #define CHACHA_CTR_SIZE 16 | |
47 | #define CHACHA_BLK_SIZE 64 | |
7dcb2186 | 48 | |
7dcb2186 | 49 | #endif |