include/openssl/poly1305.h

/* 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_POLY1305_H
#define OPENSSL_HEADER_POLY1305_H

#include <openssl/base.h>

#ifdef  __cplusplus
extern "C" {
#endif


typedef union {
  double align;
  uint8_t bytes[512];
} poly1305_state;

/* CRYPTO_poly1305_init sets up |state| so that it can be used to calculate an
 * authentication tag with the one-time key |key|. Note that |key| is a
 * one-time key and therefore there is no `reset' method because that would
 * enable several messages to be authenticated with the same key. */
OPENSSL_EXPORT void CRYPTO_poly1305_init(poly1305_state* state,
                                         const uint8_t key[32]);

/* CRYPTO_poly1305_update processes |in_len| bytes from |in|. It can be called
 * zero or more times after poly1305_init. */
OPENSSL_EXPORT void CRYPTO_poly1305_update(poly1305_state* state,
                                           const uint8_t* in,
                                           size_t in_len);

/* CRYPTO_poly1305_finish completes the poly1305 calculation and writes a 16
 * byte authentication tag to |mac|. The |mac| address must be 16-byte
 * aligned. */
OPENSSL_EXPORT void CRYPTO_poly1305_finish(poly1305_state* state,
                                           uint8_t mac[16]);


#if defined(__cplusplus)
}  /* extern C */
#endif

#endif  /* OPENSSL_HEADER_POLY1305_H */