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42 lines
1.6 KiB
42 lines
1.6 KiB
/* |
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* Copyright 2015-2018 The OpenSSL Project Authors. All Rights Reserved. |
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* |
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* Licensed under the OpenSSL license (the "License"). You may not use |
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* this file except in compliance with the License. You can obtain a copy |
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* in the file LICENSE in the source distribution or at |
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* https://www.openssl.org/source/license.html |
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*/ |
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#ifndef OSSL_CRYPTO_CHACHA_H |
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#define OSSL_CRYPTO_CHACHA_H |
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#include <stddef.h> |
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/* |
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* ChaCha20_ctr32 encrypts |len| bytes from |inp| with the given key and |
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* nonce and writes the result to |out|, which may be equal to |inp|. |
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* The |key| is not 32 bytes of verbatim key material though, but the |
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* said material collected into 8 32-bit elements array in host byte |
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* order. Same approach applies to nonce: the |counter| argument is |
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* pointer to concatenated nonce and counter values collected into 4 |
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* 32-bit elements. This, passing crypto material collected into 32-bit |
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* elements as opposite to passing verbatim byte vectors, is chosen for |
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* efficiency in multi-call scenarios. |
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*/ |
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void ChaCha20_ctr32(unsigned char *out, const unsigned char *inp, |
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size_t len, const unsigned int key[8], |
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const unsigned int counter[4]); |
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/* |
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* You can notice that there is no key setup procedure. Because it's |
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* as trivial as collecting bytes into 32-bit elements, it's reckoned |
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* that below macro is sufficient. |
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*/ |
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#define CHACHA_U8TOU32(p) ( \ |
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((unsigned int)(p)[0]) | ((unsigned int)(p)[1]<<8) | \ |
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((unsigned int)(p)[2]<<16) | ((unsigned int)(p)[3]<<24) ) |
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#define CHACHA_KEY_SIZE 32 |
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#define CHACHA_CTR_SIZE 16 |
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#define CHACHA_BLK_SIZE 64 |
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#endif
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