/* poly1305.h

   Poly1305 message authentication code.

   Copyright (C) 2013 Nikos Mavrogiannopoulos

   Copyright (C) 2013, 2014 Niels Möller

   This file is part of GNU Nettle.

   GNU Nettle is free software: you can redistribute it and/or

   modify it under the terms of either:

     * the GNU Lesser General Public License as published by the Free

       Software Foundation; either version 3 of the License, or (at your

       option) any later version.

   or

     * the GNU General Public License as published by the Free

       Software Foundation; either version 2 of the License, or (at your

       option) any later version.

   or both in parallel, as here.

   GNU Nettle is distributed in the hope that it will be useful,

   but WITHOUT ANY WARRANTY; without even the implied warranty of

   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

   General Public License for more details.

   You should have received copies of the GNU General Public License and

   the GNU Lesser General Public License along with this program.  If

   not, see http://www.gnu.org/licenses/.

*/

#ifndef GNUTLS_LIB_NETTLE_BACKPORT_NETTLE_POLY1305_H_INCLUDED

#define GNUTLS_LIB_NETTLE_BACKPORT_NETTLE_POLY1305_H_INCLUDED

#include <nettle/aes.h>

#ifdef __cplusplus

extern "C" {

#endif

/* Name mangling */

#define poly1305_aes_set_key gnutls_nettle_backport_poly1305_aes_set_key

#define poly1305_aes_set_nonce gnutls_nettle_backport_poly1305_aes_set_nonce

#define poly1305_aes_update gnutls_nettle_backport_poly1305_aes_update

#define poly1305_aes_digest gnutls_nettle_backport_poly1305_aes_digest

/* Low level functions/macros for the poly1305 construction. */

#define POLY1305_BLOCK_SIZE 16

struct poly1305_ctx {

  /* Key, 128-bit value and some cached multiples. */

  union

  {

    uint32_t r32[6];

    uint64_t r64[3];

  } r;

  uint32_t s32[3];

  /* State, represented as words of 26, 32 or 64 bits, depending on

     implementation. */

  /* High bits first, to maintain alignment. */

  uint32_t hh;

  union

  {

    uint32_t h32[4];

    uint64_t h64[2];

  } h;

};

/* poly1305-aes */

#define POLY1305_AES_KEY_SIZE 32

#define POLY1305_AES_DIGEST_SIZE 16

#define POLY1305_AES_NONCE_SIZE 16

struct poly1305_aes_ctx

{

  /* Keep aes context last, to make it possible to use a general

     poly1305_update if other variants are added. */

  struct poly1305_ctx pctx;

  uint8_t block[POLY1305_BLOCK_SIZE];

  unsigned index;

  uint8_t nonce[POLY1305_BLOCK_SIZE];

  struct aes128_ctx aes;

};

/* Also initialize the nonce to zero. */

void

poly1305_aes_set_key (struct poly1305_aes_ctx *ctx, const uint8_t *key);

/* Optional, if not used, messages get incrementing nonces starting

   from zero. */

void

poly1305_aes_set_nonce (struct poly1305_aes_ctx *ctx,

		        const uint8_t *nonce);

/* Update is not aes-specific, but since this is the only implemented

   variant, we need no more general poly1305_update. */

void

poly1305_aes_update (struct poly1305_aes_ctx *ctx, size_t length, const uint8_t *data);

/* Also increments the nonce */

void

poly1305_aes_digest (struct poly1305_aes_ctx *ctx,

	       	     size_t length, uint8_t *digest);

#ifdef __cplusplus

}

#endif

#endif /* GNUTLS_LIB_NETTLE_BACKPORT_NETTLE_POLY1305_H_INCLUDED */