crypto/des/fcrypt_b.c

/*
 * Copyright 1995-2020 The OpenSSL Project Authors. All Rights Reserved.
 *
 * Licensed under the Apache License 2.0 (the "License").  You may not use
 * this file except in compliance with the License.  You can obtain a copy
 * in the file LICENSE in the source distribution or at
 * https://www.openssl.org/source/license.html
 */

/*
 * DES low level APIs are deprecated for public use, but still ok for internal
 * use.
 */
#include "internal/deprecated.h"

#include <stdio.h>

#define DES_FCRYPT
#include "des_local.h"
#undef DES_FCRYPT

#undef PERM_OP
#define PERM_OP(a, b, t, n, m) ((t) = ((((a) >> (n)) ^ (b)) & (m)), \
    (b) ^= (t),                                                     \
    (a) ^= ((t) << (n)))

#undef HPERM_OP
#define HPERM_OP(a, t, n, m) ((t) = ((((a) << (16 - (n))) ^ (a)) & (m)), \
    (a) = (a) ^ (t) ^ (t >> (16 - (n))))

void fcrypt_body(DES_LONG *out, DES_key_schedule *ks, DES_LONG Eswap0,
    DES_LONG Eswap1)
{
    register DES_LONG l, r, t, u;
    register DES_LONG *s;
    register int j;
    register DES_LONG E0, E1;

    l = 0;
    r = 0;

    s = (DES_LONG *)ks;
    E0 = Eswap0;
    E1 = Eswap1;

    for (j = 0; j < 25; j++) {
        D_ENCRYPT(l, r, 0); /* 1 */
        D_ENCRYPT(r, l, 2); /* 2 */
        D_ENCRYPT(l, r, 4); /* 3 */
        D_ENCRYPT(r, l, 6); /* 4 */
        D_ENCRYPT(l, r, 8); /* 5 */
        D_ENCRYPT(r, l, 10); /* 6 */
        D_ENCRYPT(l, r, 12); /* 7 */
        D_ENCRYPT(r, l, 14); /* 8 */
        D_ENCRYPT(l, r, 16); /* 9 */
        D_ENCRYPT(r, l, 18); /* 10 */
        D_ENCRYPT(l, r, 20); /* 11 */
        D_ENCRYPT(r, l, 22); /* 12 */
        D_ENCRYPT(l, r, 24); /* 13 */
        D_ENCRYPT(r, l, 26); /* 14 */
        D_ENCRYPT(l, r, 28); /* 15 */
        D_ENCRYPT(r, l, 30); /* 16 */
        t = l;
        l = r;
        r = t;
    }
    l = ROTATE(l, 3) & 0xffffffffL;
    r = ROTATE(r, 3) & 0xffffffffL;

    PERM_OP(l, r, t, 1, 0x55555555L);
    PERM_OP(r, l, t, 8, 0x00ff00ffL);
    PERM_OP(l, r, t, 2, 0x33333333L);
    PERM_OP(r, l, t, 16, 0x0000ffffL);
    PERM_OP(l, r, t, 4, 0x0f0f0f0fL);

    out[0] = r;
    out[1] = l;
}