internal-ghash.h

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/*
 * Copyright (C) 2021 Southern Storm Software, Pty Ltd.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included
 * in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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 * DEALINGS IN THE SOFTWARE.
 */

#ifndef LW_INTERNAL_GHASH_H
#define LW_INTERNAL_GHASH_H

#include "internal-util.h"
#include <stddef.h>

#ifdef __cplusplus
extern "C" {
#endif

#if defined(__AVR__)
#define GHASH_SHOUP_4BIT 0
#else
#define GHASH_SHOUP_4BIT 1
#endif

typedef struct
{
    uint64_t c[2];          
} gf128_value_t;

typedef struct
{
#if GHASH_SHOUP_4BIT
    gf128_value_t H[16];    
#else
    gf128_value_t H;        
#endif
    uint8_t Y[16];          
    uint32_t posn;          
} ghash_state_t;

void ghash_init(ghash_state_t *state, const unsigned char *key);

void ghash_update(ghash_state_t *state, const unsigned char *data, size_t size);

void ghash_pad(ghash_state_t *state);

void ghash_finalize(ghash_state_t *state, unsigned char *hash);

#ifdef __cplusplus
}
#endif

#endif