text: /* Copyright (c) 2014, Google Inc.
   *
   * Permission to use, copy, modify, and/or distribute this software for any
   * purpose with or without fee is hereby granted, provided that the above
   * copyright notice and this permission notice appear in all copies.
   *
   * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
   * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
   * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
   * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
   * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
   * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
   * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */
  
  #ifndef OPENSSL_HEADER_CHACHA_H
  #define OPENSSL_HEADER_CHACHA_H
  
  #include <openssl/base.h>
  
  #ifdef  __cplusplus
  extern "C" {
  #endif
  
  
  /* CRYPTO_chacha_20 encrypts |in_len| bytes from |in| with the given key and
   * nonce and writes the result to |out|, which may be equal to |in|. The
   * initial block counter is specified by |counter|. */
  OPENSSL_EXPORT void CRYPTO_chacha_20(uint8_t *out, const uint8_t *in,
                                       size_t in_len, const uint8_t key[32],
                                       const uint8_t nonce[8], size_t counter);
  
  
  #if defined(__cplusplus)
  }  /* extern C */
  #endif
  
  #endif  /* OPENSSL_HEADER_CHACHA_H */
  