internal-ascon.h

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/*
 * Copyright (C) 2020 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_ASCON_H
#define LW_INTERNAL_ASCON_H

#include "internal-util.h"

#ifdef __cplusplus
extern "C" {
#endif

#if !defined(__AVR__)
#define ASCON_SLICED 1
#else
#define ASCON_SLICED 0
#endif

typedef union
{
    uint64_t S[5];      
    uint32_t W[10];     
    uint8_t B[40];      
} ascon_state_t;

void ascon_permute(ascon_state_t *state, uint8_t first_round);

#if ASCON_SLICED

void ascon_to_sliced(ascon_state_t *state);

void ascon_from_sliced(ascon_state_t *state);

void ascon_permute_sliced(ascon_state_t *state, uint8_t first_round);

/* http://programming.sirrida.de/perm_fn.html#bit_permute_step */
#define ascon_bit_permute_step(_y, mask, shift) \
    do { \
        uint32_t y = (_y); \
        uint32_t t = ((y >> (shift)) ^ y) & (mask); \
        (_y) = (y ^ t) ^ (t << (shift)); \
    } while (0)

/* Separates a 32-bit word into two 16-bit halves with all the even
 * bits in the bottom half and all the odd bits in the top half.
 *
 * Permutation generated with "http://programming.sirrida.de/calcperm.php"
 *
 * P = [0 16 1 17 2 18 3 19 4 20 5 21 6 22 7 23 8 24
 *      9 25 10 26 11 27 12 28 13 29 14 30 15 31]
 */
#define ascon_separate(x) \
    do { \
        ascon_bit_permute_step((x), 0x22222222, 1); \
        ascon_bit_permute_step((x), 0x0c0c0c0c, 2); \
        ascon_bit_permute_step((x), 0x00f000f0, 4); \
        ascon_bit_permute_step((x), 0x0000ff00, 8); \
    } while (0)
#define ascon_combine(x) \
    do { \
        ascon_bit_permute_step((x), 0x0000aaaa, 15); \
        ascon_bit_permute_step((x), 0x0000cccc, 14); \
        ascon_bit_permute_step((x), 0x0000f0f0, 12); \
        ascon_bit_permute_step((x), 0x0000ff00, 8); \
    } while (0)

#define ascon_set_sliced(state, data, offset) \
    do { \
        ascon_state_t *s = (state); \
        uint32_t high = be_load_word32((data)); \
        uint32_t low  = be_load_word32((data) + 4); \
        ascon_separate(high); \
        ascon_separate(low); \
        s->W[(offset) * 2] = (high << 16) | (low & 0x0000FFFFU); \
        s->W[(offset) * 2 + 1] = (high & 0xFFFF0000U) | (low >> 16); \
    } while (0)

#define ascon_absorb_sliced(state, data, offset) \
    do { \
        ascon_state_t *s = (state); \
        uint32_t high = be_load_word32((data)); \
        uint32_t low  = be_load_word32((data) + 4); \
        ascon_separate(high); \
        ascon_separate(low); \
        s->W[(offset) * 2] ^= (high << 16) | (low & 0x0000FFFFU); \
        s->W[(offset) * 2 + 1] ^= (high & 0xFFFF0000U) | (low >> 16); \
    } while (0)

#define ascon_absorb32_low_sliced(state, data, offset) \
    do { \
        ascon_state_t *s = (state); \
        uint32_t low  = be_load_word32((data)); \
        ascon_separate(low); \
        s->W[(offset) * 2] ^= (low & 0x0000FFFFU); \
        s->W[(offset) * 2 + 1] ^= (low >> 16); \
    } while (0)

#define ascon_absorb32_high_sliced(state, data, offset) \
    do { \
        ascon_state_t *s = (state); \
        uint32_t high = be_load_word32((data)); \
        ascon_separate(high); \
        s->W[(offset) * 2] ^= (high << 16); \
        s->W[(offset) * 2 + 1] ^= (high & 0xFFFF0000U); \
    } while (0)

#define ascon_squeeze_sliced(state, data, offset) \
    do { \
        ascon_state_t *s = (state); \
        uint32_t high, low; \
        high = (s->W[(offset) * 2] >> 16) | \
               (s->W[(offset) * 2 + 1] & 0xFFFF0000U); \
        low  = (s->W[(offset) * 2] & 0x0000FFFFU) | \
               (s->W[(offset) * 2 + 1] << 16); \
        ascon_combine(high); \
        ascon_combine(low); \
        be_store_word32((data), high); \
        be_store_word32((data) + 4, low); \
    } while (0)

#define ascon_encrypt_sliced(state, c, m, offset) \
    do { \
        ascon_state_t *s = (state); \
        uint32_t high = be_load_word32((m)); \
        uint32_t low  = be_load_word32((m) + 4); \
        ascon_separate(high); \
        ascon_separate(low); \
        s->W[(offset) * 2] ^= (high << 16) | (low & 0x0000FFFFU); \
        s->W[(offset) * 2 + 1] ^= (high & 0xFFFF0000U) | (low >> 16); \
        high = (s->W[(offset) * 2] >> 16) | \
               (s->W[(offset) * 2 + 1] & 0xFFFF0000U); \
        low  = (s->W[(offset) * 2] & 0x0000FFFFU) | \
               (s->W[(offset) * 2 + 1] << 16); \
        ascon_combine(high); \
        ascon_combine(low); \
        be_store_word32((c), high); \
        be_store_word32((c) + 4, low); \
    } while (0)

#define ascon_decrypt_sliced(state, m, c, offset) \
    do { \
        ascon_state_t *s = (state); \
        uint32_t high, low, high2, low2; \
        high = be_load_word32((c)); \
        low  = be_load_word32((c) + 4); \
        ascon_separate(high); \
        ascon_separate(low); \
        high2 = high ^ ((s->W[(offset) * 2] >> 16) | \
                        (s->W[(offset) * 2 + 1] & 0xFFFF0000U)); \
        low2 = low ^ ((s->W[(offset) * 2] & 0x0000FFFFU) | \
                      (s->W[(offset) * 2 + 1] << 16)); \
        s->W[(offset) * 2] = (high << 16) | (low & 0x0000FFFFU); \
        s->W[(offset) * 2 + 1] = (high & 0xFFFF0000U) | (low >> 16); \
        ascon_combine(high2); \
        ascon_combine(low2); \
        be_store_word32((m), high2); \
        be_store_word32((m) + 4, low2); \
    } while (0)

#endif /* ASCON_SLICED */

#ifdef __cplusplus
}
#endif

#endif