/*
 * serpent.c: Implementation of the Serpent block cipher
 */
/*
 * This file is Free Software.  It has been modified to as part of its
 * incorporation into secnet.
 *
 * Copyright 1998      Ross Anderson, Eli Biham, Lars Knudsen
 * Copyright 1995-2001 Stephen Early <steve@greenend.org.uk>
 * Copyright 2011-2013 Ian Jackson
 *
 * For more information about Serpent see
 * http://www.cl.cam.ac.uk/users/rja14/serpent.html
 *
 * You may redistribute secnet as a whole and/or modify it under the
 * terms of the GNU General Public License as published by the Free
 * Software Foundation; either version 3, or (at your option) any
 * later version.
 *
 * You may redistribute this file and/or modify it under the terms of
 * the GNU General Public License as published by the Free Software
 * Foundation; either version 2, or (at your option) any later
 * version.
 *
 * This software 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 a copy of the GNU General Public License
 * along with this software; if not, see
 * https://www.gnu.org/licenses/gpl.html.
 */

#include <stdint.h>

#include "hexdebug.h"
#include "serpent.h"
#include "serpentsboxes.h"

#ifdef SERPENT_BIGENDIAN

#define GETPUT_CP(bytenum) \
    (((basep) + (lenbytes) - (offset) - 4)[(bytenum)])

#define SERPENT_DECORATE(func) serpentbe_##func

#else /* !defined(SERPENT_BIGENDIAN) */

#define GETPUT_CP(bytenum) \
    (((basep) + (offset))[3-(bytenum)])

#define SERPENT_DECORATE(func) serpent_##func

#endif /* !defined(SERPENT_BIGENDIAN) */

#if 0

#include <stdio.h>

static void SERP_DEBUG(const char *str1,
		       const void *ary, int sz,
		       const char *str2)
{
    fprintf(stderr,"%s",str1);
    hexdebug(stderr,ary,sz);
    fprintf(stderr,"%s",str2);
}

#else

#define SERP_DEBUG(str1,aryv,sz,str2) /*empty*/

#endif


static uint32_t serpent_get_32bit(const uint8_t *basep,
				  int lenbytes, int offset)
{
    return (((uint32_t)GETPUT_CP(0) << 24) |
	    ((uint32_t)GETPUT_CP(1) << 16) |
	    ((uint32_t)GETPUT_CP(2) << +8) |
	    ((uint32_t)GETPUT_CP(3)));
}

static void serpent_put_32bit(uint8_t *basep, int lenbytes, int offset, uint32_t value)
{
    GETPUT_CP(0) = (char)((value) >> 24);
    GETPUT_CP(1) = (char)((value) >> 16);
    GETPUT_CP(2) = (char)((value) >> 8);
    GETPUT_CP(3) = (char)(value);
}

void SERPENT_DECORATE(makekey)(struct keyInstance *key, int keyLen,
	    const uint8_t *keyMaterial)
{
    int i;
    uint32_t j;
    uint32_t w[132],k[132];

    SERP_DEBUG("SERPENT makekey ",keyMaterial,keyLen/8,"\n");

    for(i=0; i<keyLen/32; i++)
	w[i]=serpent_get_32bit(keyMaterial, keyLen/8, i*4);
    if(keyLen<256)
	w[i]=(serpent_get_32bit(keyMaterial, keyLen/8, i*4)
              & ((1L<<((keyLen&31)))-1)) | (1L<<((keyLen&31)));
    for(i++; i<8; i++)
	w[i]=0;
    for(i=8; i<16; i++)
	w[i]=ROL(w[i-8]^w[i-5]^w[i-3]^w[i-1]^PHI^(i-8),11);
    for(i=0; i<8; i++)
	w[i]=w[i+8];
    for(i=8; i<132; i++)
	w[i]=ROL(w[i-8]^w[i-5]^w[i-3]^w[i-1]^PHI^i,11);

    RND03(w[  0], w[  1], w[  2], w[  3], k[  0], k[  1], k[  2], k[  3]);
    RND02(w[  4], w[  5], w[  6], w[  7], k[  4], k[  5], k[  6], k[  7]);
    RND01(w[  8], w[  9], w[ 10], w[ 11], k[  8], k[  9], k[ 10], k[ 11]);
    RND00(w[ 12], w[ 13], w[ 14], w[ 15], k[ 12], k[ 13], k[ 14], k[ 15]);
    RND31(w[ 16], w[ 17], w[ 18], w[ 19], k[ 16], k[ 17], k[ 18], k[ 19]);
    RND30(w[ 20], w[ 21], w[ 22], w[ 23], k[ 20], k[ 21], k[ 22], k[ 23]);
    RND29(w[ 24], w[ 25], w[ 26], w[ 27], k[ 24], k[ 25], k[ 26], k[ 27]);
    RND28(w[ 28], w[ 29], w[ 30], w[ 31], k[ 28], k[ 29], k[ 30], k[ 31]);
    RND27(w[ 32], w[ 33], w[ 34], w[ 35], k[ 32], k[ 33], k[ 34], k[ 35]);
    RND26(w[ 36], w[ 37], w[ 38], w[ 39], k[ 36], k[ 37], k[ 38], k[ 39]);
    RND25(w[ 40], w[ 41], w[ 42], w[ 43], k[ 40], k[ 41], k[ 42], k[ 43]);
    RND24(w[ 44], w[ 45], w[ 46], w[ 47], k[ 44], k[ 45], k[ 46], k[ 47]);
    RND23(w[ 48], w[ 49], w[ 50], w[ 51], k[ 48], k[ 49], k[ 50], k[ 51]);
    RND22(w[ 52], w[ 53], w[ 54], w[ 55], k[ 52], k[ 53], k[ 54], k[ 55]);
    RND21(w[ 56], w[ 57], w[ 58], w[ 59], k[ 56], k[ 57], k[ 58], k[ 59]);
    RND20(w[ 60], w[ 61], w[ 62], w[ 63], k[ 60], k[ 61], k[ 62], k[ 63]);
    RND19(w[ 64], w[ 65], w[ 66], w[ 67], k[ 64], k[ 65], k[ 66], k[ 67]);
    RND18(w[ 68], w[ 69], w[ 70], w[ 71], k[ 68], k[ 69], k[ 70], k[ 71]);
    RND17(w[ 72], w[ 73], w[ 74], w[ 75], k[ 72], k[ 73], k[ 74], k[ 75]);
    RND16(w[ 76], w[ 77], w[ 78], w[ 79], k[ 76], k[ 77], k[ 78], k[ 79]);
    RND15(w[ 80], w[ 81], w[ 82], w[ 83], k[ 80], k[ 81], k[ 82], k[ 83]);
    RND14(w[ 84], w[ 85], w[ 86], w[ 87], k[ 84], k[ 85], k[ 86], k[ 87]);
    RND13(w[ 88], w[ 89], w[ 90], w[ 91], k[ 88], k[ 89], k[ 90], k[ 91]);
    RND12(w[ 92], w[ 93], w[ 94], w[ 95], k[ 92], k[ 93], k[ 94], k[ 95]);
    RND11(w[ 96], w[ 97], w[ 98], w[ 99], k[ 96], k[ 97], k[ 98], k[ 99]);
    RND10(w[100], w[101], w[102], w[103], k[100], k[101], k[102], k[103]);
    RND09(w[104], w[105], w[106], w[107], k[104], k[105], k[106], k[107]);
    RND08(w[108], w[109], w[110], w[111], k[108], k[109], k[110], k[111]);
    RND07(w[112], w[113], w[114], w[115], k[112], k[113], k[114], k[115]);
    RND06(w[116], w[117], w[118], w[119], k[116], k[117], k[118], k[119]);
    RND05(w[120], w[121], w[122], w[123], k[120], k[121], k[122], k[123]);
    RND04(w[124], w[125], w[126], w[127], k[124], k[125], k[126], k[127]);
    RND03(w[128], w[129], w[130], w[131], k[128], k[129], k[130], k[131]);

    for(i=0; i<=32; i++)
	for(j=0; j<4; j++)
	    key->subkeys[i][j] = k[4*i+j];
}

void SERPENT_DECORATE(encrypt)(struct keyInstance *key,
		     const uint8_t plaintext[16], 
		     uint8_t ciphertext[16])
{
    register uint32_t x0, x1, x2, x3;
    register uint32_t y0, y1, y2, y3;

    SERP_DEBUG("SERPENT encrypt ",plaintext,16," ->");

    x0=serpent_get_32bit(plaintext,16,+0);
    x1=serpent_get_32bit(plaintext,16,+4);
    x2=serpent_get_32bit(plaintext,16,+8);
    x3=serpent_get_32bit(plaintext,16,12);

    /* Start to encrypt the plaintext x */
    keying(x0, x1, x2, x3, key->subkeys[ 0]);
    RND00(x0, x1, x2, x3, y0, y1, y2, y3);
    transform(y0, y1, y2, y3, x0, x1, x2, x3);
    keying(x0, x1, x2, x3, key->subkeys[ 1]);
    RND01(x0, x1, x2, x3, y0, y1, y2, y3);
    transform(y0, y1, y2, y3, x0, x1, x2, x3);
    keying(x0, x1, x2, x3, key->subkeys[ 2]);
    RND02(x0, x1, x2, x3, y0, y1, y2, y3);
    transform(y0, y1, y2, y3, x0, x1, x2, x3);
    keying(x0, x1, x2, x3, key->subkeys[ 3]);
    RND03(x0, x1, x2, x3, y0, y1, y2, y3);
    transform(y0, y1, y2, y3, x0, x1, x2, x3);
    keying(x0, x1, x2, x3, key->subkeys[ 4]);
    RND04(x0, x1, x2, x3, y0, y1, y2, y3);
    transform(y0, y1, y2, y3, x0, x1, x2, x3);
    keying(x0, x1, x2, x3, key->subkeys[ 5]);
    RND05(x0, x1, x2, x3, y0, y1, y2, y3);
    transform(y0, y1, y2, y3, x0, x1, x2, x3);
    keying(x0, x1, x2, x3, key->subkeys[ 6]);
    RND06(x0, x1, x2, x3, y0, y1, y2, y3);
    transform(y0, y1, y2, y3, x0, x1, x2, x3);
    keying(x0, x1, x2, x3, key->subkeys[ 7]);
    RND07(x0, x1, x2, x3, y0, y1, y2, y3);
    transform(y0, y1, y2, y3, x0, x1, x2, x3);
    keying(x0, x1, x2, x3, key->subkeys[ 8]);
    RND08(x0, x1, x2, x3, y0, y1, y2, y3);
    transform(y0, y1, y2, y3, x0, x1, x2, x3);
    keying(x0, x1, x2, x3, key->subkeys[ 9]);
    RND09(x0, x1, x2, x3, y0, y1, y2, y3);
    transform(y0, y1, y2, y3, x0, x1, x2, x3);
    keying(x0, x1, x2, x3, key->subkeys[10]);
    RND10(x0, x1, x2, x3, y0, y1, y2, y3);
    transform(y0, y1, y2, y3, x0, x1, x2, x3);
    keying(x0, x1, x2, x3, key->subkeys[11]);
    RND11(x0, x1, x2, x3, y0, y1, y2, y3);
    transform(y0, y1, y2, y3, x0, x1, x2, x3);
    keying(x0, x1, x2, x3, key->subkeys[12]);
    RND12(x0, x1, x2, x3, y0, y1, y2, y3);
    transform(y0, y1, y2, y3, x0, x1, x2, x3);
    keying(x0, x1, x2, x3, key->subkeys[13]);
    RND13(x0, x1, x2, x3, y0, y1, y2, y3);
    transform(y0, y1, y2, y3, x0, x1, x2, x3);
    keying(x0, x1, x2, x3, key->subkeys[14]);
    RND14(x0, x1, x2, x3, y0, y1, y2, y3);
    transform(y0, y1, y2, y3, x0, x1, x2, x3);
    keying(x0, x1, x2, x3, key->subkeys[15]);
    RND15(x0, x1, x2, x3, y0, y1, y2, y3);
    transform(y0, y1, y2, y3, x0, x1, x2, x3);
    keying(x0, x1, x2, x3, key->subkeys[16]);
    RND16(x0, x1, x2, x3, y0, y1, y2, y3);
    transform(y0, y1, y2, y3, x0, x1, x2, x3);
    keying(x0, x1, x2, x3, key->subkeys[17]);
    RND17(x0, x1, x2, x3, y0, y1, y2, y3);
    transform(y0, y1, y2, y3, x0, x1, x2, x3);
    keying(x0, x1, x2, x3, key->subkeys[18]);
    RND18(x0, x1, x2, x3, y0, y1, y2, y3);
    transform(y0, y1, y2, y3, x0, x1, x2, x3);
    keying(x0, x1, x2, x3, key->subkeys[19]);
    RND19(x0, x1, x2, x3, y0, y1, y2, y3);
    transform(y0, y1, y2, y3, x0, x1, x2, x3);
    keying(x0, x1, x2, x3, key->subkeys[20]);
    RND20(x0, x1, x2, x3, y0, y1, y2, y3);
    transform(y0, y1, y2, y3, x0, x1, x2, x3);
    keying(x0, x1, x2, x3, key->subkeys[21]);
    RND21(x0, x1, x2, x3, y0, y1, y2, y3);
    transform(y0, y1, y2, y3, x0, x1, x2, x3);
    keying(x0, x1, x2, x3, key->subkeys[22]);
    RND22(x0, x1, x2, x3, y0, y1, y2, y3);
    transform(y0, y1, y2, y3, x0, x1, x2, x3);
    keying(x0, x1, x2, x3, key->subkeys[23]);
    RND23(x0, x1, x2, x3, y0, y1, y2, y3);
    transform(y0, y1, y2, y3, x0, x1, x2, x3);
    keying(x0, x1, x2, x3, key->subkeys[24]);
    RND24(x0, x1, x2, x3, y0, y1, y2, y3);
    transform(y0, y1, y2, y3, x0, x1, x2, x3);
    keying(x0, x1, x2, x3, key->subkeys[25]);
    RND25(x0, x1, x2, x3, y0, y1, y2, y3);
    transform(y0, y1, y2, y3, x0, x1, x2, x3);
    keying(x0, x1, x2, x3, key->subkeys[26]);
    RND26(x0, x1, x2, x3, y0, y1, y2, y3);
    transform(y0, y1, y2, y3, x0, x1, x2, x3);
    keying(x0, x1, x2, x3, key->subkeys[27]);
    RND27(x0, x1, x2, x3, y0, y1, y2, y3);
    transform(y0, y1, y2, y3, x0, x1, x2, x3);
    keying(x0, x1, x2, x3, key->subkeys[28]);
    RND28(x0, x1, x2, x3, y0, y1, y2, y3);
    transform(y0, y1, y2, y3, x0, x1, x2, x3);
    keying(x0, x1, x2, x3, key->subkeys[29]);
    RND29(x0, x1, x2, x3, y0, y1, y2, y3);
    transform(y0, y1, y2, y3, x0, x1, x2, x3);
    keying(x0, x1, x2, x3, key->subkeys[30]);
    RND30(x0, x1, x2, x3, y0, y1, y2, y3);
    transform(y0, y1, y2, y3, x0, x1, x2, x3);
    keying(x0, x1, x2, x3, key->subkeys[31]);
    RND31(x0, x1, x2, x3, y0, y1, y2, y3);
    x0 = y0; x1 = y1; x2 = y2; x3 = y3;
    keying(x0, x1, x2, x3, key->subkeys[32]);
    /* The ciphertext is now in x */

    serpent_put_32bit(ciphertext,16,+0, x0);
    serpent_put_32bit(ciphertext,16,+4, x1);
    serpent_put_32bit(ciphertext,16,+8, x2);
    serpent_put_32bit(ciphertext,16,12, x3);

    SERP_DEBUG(" ",ciphertext,16,"\n");
}

void SERPENT_DECORATE(decrypt)(struct keyInstance *key,
		     const uint8_t ciphertext[16],
		     uint8_t plaintext[16])
{
    register uint32_t x0, x1, x2, x3;
    register uint32_t y0, y1, y2, y3;

    SERP_DEBUG("SERPENT decrypt ",ciphertext,16," ->");

    x0=serpent_get_32bit(ciphertext,16,+0);
    x1=serpent_get_32bit(ciphertext,16,+4);
    x2=serpent_get_32bit(ciphertext,16,+8);
    x3=serpent_get_32bit(ciphertext,16,12);

    /* Start to decrypt the ciphertext x */
    keying(x0, x1, x2, x3, key->subkeys[32]);
    InvRND31(x0, x1, x2, x3, y0, y1, y2, y3);
    keying(y0, y1, y2, y3, key->subkeys[31]);
    inv_transform(y0, y1, y2, y3, x0, x1, x2, x3);
    InvRND30(x0, x1, x2, x3, y0, y1, y2, y3);
    keying(y0, y1, y2, y3, key->subkeys[30]);
    inv_transform(y0, y1, y2, y3, x0, x1, x2, x3);
    InvRND29(x0, x1, x2, x3, y0, y1, y2, y3);
    keying(y0, y1, y2, y3, key->subkeys[29]);
    inv_transform(y0, y1, y2, y3, x0, x1, x2, x3);
    InvRND28(x0, x1, x2, x3, y0, y1, y2, y3);
    keying(y0, y1, y2, y3, key->subkeys[28]);
    inv_transform(y0, y1, y2, y3, x0, x1, x2, x3);
    InvRND27(x0, x1, x2, x3, y0, y1, y2, y3);
    keying(y0, y1, y2, y3, key->subkeys[27]);
    inv_transform(y0, y1, y2, y3, x0, x1, x2, x3);
    InvRND26(x0, x1, x2, x3, y0, y1, y2, y3);
    keying(y0, y1, y2, y3, key->subkeys[26]);
    inv_transform(y0, y1, y2, y3, x0, x1, x2, x3);
    InvRND25(x0, x1, x2, x3, y0, y1, y2, y3);
    keying(y0, y1, y2, y3, key->subkeys[25]);
    inv_transform(y0, y1, y2, y3, x0, x1, x2, x3);
    InvRND24(x0, x1, x2, x3, y0, y1, y2, y3);
    keying(y0, y1, y2, y3, key->subkeys[24]);
    inv_transform(y0, y1, y2, y3, x0, x1, x2, x3);
    InvRND23(x0, x1, x2, x3, y0, y1, y2, y3);
    keying(y0, y1, y2, y3, key->subkeys[23]);
    inv_transform(y0, y1, y2, y3, x0, x1, x2, x3);
    InvRND22(x0, x1, x2, x3, y0, y1, y2, y3);
    keying(y0, y1, y2, y3, key->subkeys[22]);
    inv_transform(y0, y1, y2, y3, x0, x1, x2, x3);
    InvRND21(x0, x1, x2, x3, y0, y1, y2, y3);
    keying(y0, y1, y2, y3, key->subkeys[21]);
    inv_transform(y0, y1, y2, y3, x0, x1, x2, x3);
    InvRND20(x0, x1, x2, x3, y0, y1, y2, y3);
    keying(y0, y1, y2, y3, key->subkeys[20]);
    inv_transform(y0, y1, y2, y3, x0, x1, x2, x3);
    InvRND19(x0, x1, x2, x3, y0, y1, y2, y3);
    keying(y0, y1, y2, y3, key->subkeys[19]);
    inv_transform(y0, y1, y2, y3, x0, x1, x2, x3);
    InvRND18(x0, x1, x2, x3, y0, y1, y2, y3);
    keying(y0, y1, y2, y3, key->subkeys[18]);
    inv_transform(y0, y1, y2, y3, x0, x1, x2, x3);
    InvRND17(x0, x1, x2, x3, y0, y1, y2, y3);
    keying(y0, y1, y2, y3, key->subkeys[17]);
    inv_transform(y0, y1, y2, y3, x0, x1, x2, x3);
    InvRND16(x0, x1, x2, x3, y0, y1, y2, y3);
    keying(y0, y1, y2, y3, key->subkeys[16]);
    inv_transform(y0, y1, y2, y3, x0, x1, x2, x3);
    InvRND15(x0, x1, x2, x3, y0, y1, y2, y3);
    keying(y0, y1, y2, y3, key->subkeys[15]);
    inv_transform(y0, y1, y2, y3, x0, x1, x2, x3);
    InvRND14(x0, x1, x2, x3, y0, y1, y2, y3);
    keying(y0, y1, y2, y3, key->subkeys[14]);
    inv_transform(y0, y1, y2, y3, x0, x1, x2, x3);
    InvRND13(x0, x1, x2, x3, y0, y1, y2, y3);
    keying(y0, y1, y2, y3, key->subkeys[13]);
    inv_transform(y0, y1, y2, y3, x0, x1, x2, x3);
    InvRND12(x0, x1, x2, x3, y0, y1, y2, y3);
    keying(y0, y1, y2, y3, key->subkeys[12]);
    inv_transform(y0, y1, y2, y3, x0, x1, x2, x3);
    InvRND11(x0, x1, x2, x3, y0, y1, y2, y3);
    keying(y0, y1, y2, y3, key->subkeys[11]);
    inv_transform(y0, y1, y2, y3, x0, x1, x2, x3);
    InvRND10(x0, x1, x2, x3, y0, y1, y2, y3);
    keying(y0, y1, y2, y3, key->subkeys[10]);
    inv_transform(y0, y1, y2, y3, x0, x1, x2, x3);
    InvRND09(x0, x1, x2, x3, y0, y1, y2, y3);
    keying(y0, y1, y2, y3, key->subkeys[ 9]);
    inv_transform(y0, y1, y2, y3, x0, x1, x2, x3);
    InvRND08(x0, x1, x2, x3, y0, y1, y2, y3);
    keying(y0, y1, y2, y3, key->subkeys[ 8]);
    inv_transform(y0, y1, y2, y3, x0, x1, x2, x3);
    InvRND07(x0, x1, x2, x3, y0, y1, y2, y3);
    keying(y0, y1, y2, y3, key->subkeys[ 7]);
    inv_transform(y0, y1, y2, y3, x0, x1, x2, x3);
    InvRND06(x0, x1, x2, x3, y0, y1, y2, y3);
    keying(y0, y1, y2, y3, key->subkeys[ 6]);
    inv_transform(y0, y1, y2, y3, x0, x1, x2, x3);
    InvRND05(x0, x1, x2, x3, y0, y1, y2, y3);
    keying(y0, y1, y2, y3, key->subkeys[ 5]);
    inv_transform(y0, y1, y2, y3, x0, x1, x2, x3);
    InvRND04(x0, x1, x2, x3, y0, y1, y2, y3);
    keying(y0, y1, y2, y3, key->subkeys[ 4]);
    inv_transform(y0, y1, y2, y3, x0, x1, x2, x3);
    InvRND03(x0, x1, x2, x3, y0, y1, y2, y3);
    keying(y0, y1, y2, y3, key->subkeys[ 3]);
    inv_transform(y0, y1, y2, y3, x0, x1, x2, x3);
    InvRND02(x0, x1, x2, x3, y0, y1, y2, y3);
    keying(y0, y1, y2, y3, key->subkeys[ 2]);
    inv_transform(y0, y1, y2, y3, x0, x1, x2, x3);
    InvRND01(x0, x1, x2, x3, y0, y1, y2, y3);
    keying(y0, y1, y2, y3, key->subkeys[ 1]);
    inv_transform(y0, y1, y2, y3, x0, x1, x2, x3);
    InvRND00(x0, x1, x2, x3, y0, y1, y2, y3);
    x0 = y0; x1 = y1; x2 = y2; x3 = y3;
    keying(x0, x1, x2, x3, key->subkeys[ 0]);
    /* The plaintext is now in x */

    serpent_put_32bit(plaintext,16,+0, x0);
    serpent_put_32bit(plaintext,16,+4, x1);
    serpent_put_32bit(plaintext,16,+8, x2);
    serpent_put_32bit(plaintext,16,12, x3);

    SERP_DEBUG(" ",plaintext,16,"\n");
}