1 /* Copyright (c) 2014, Google Inc. 2 * 3 * Permission to use, copy, modify, and/or distribute this software for any 4 * purpose with or without fee is hereby granted, provided that the above 5 * copyright notice and this permission notice appear in all copies. 6 * 7 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 8 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 9 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY 10 * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 11 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION 12 * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN 13 * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */ 14 15 #ifndef OPENSSL_HEADER_CHACHA_H 16 #define OPENSSL_HEADER_CHACHA_H 17 18 #include <openssl/base.h> 19 20 #if defined(__cplusplus) 21 extern "C" { 22 #endif 23 24 // ChaCha20. 25 // 26 // ChaCha20 is a stream cipher. See https://tools.ietf.org/html/rfc8439. 27 28 29 // CRYPTO_chacha_20 encrypts |in_len| bytes from |in| with the given key and 30 // nonce and writes the result to |out|. If |in| and |out| alias, they must be 31 // equal. The initial block counter is specified by |counter|. 32 // 33 // This function implements a 32-bit block counter as in RFC 8439. On overflow, 34 // the counter wraps. Reusing a key, nonce, and block counter combination is not 35 // secure, so wrapping is usually a bug in the caller. While it is possible to 36 // wrap without reuse with a large initial block counter, this is not 37 // recommended and may not be portable to other ChaCha20 implementations. 38 OPENSSL_EXPORT void CRYPTO_chacha_20(uint8_t *out, const uint8_t *in, 39 size_t in_len, const uint8_t key[32], 40 const uint8_t nonce[12], uint32_t counter); 41 42 43 #if defined(__cplusplus) 44 } // extern C 45 #endif 46 47 #endif // OPENSSL_HEADER_CHACHA_H 48