/*

 * 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 "des_local.h"

void DES_pcbc_encrypt(const unsigned char *input, unsigned char *output,

                      long length, DES_key_schedule *schedule,

                      DES_cblock *ivec, int enc)

{

    register DES_LONG sin0, sin1, xor0, xor1, tout0, tout1;

    DES_LONG tin[2];

    const unsigned char *in;

    unsigned char *out, *iv;

    in = input;

    out = output;

    iv = &(*ivec)[0];

    if (enc) {

        c2l(iv, xor0);

        c2l(iv, xor1);

        for (; length > 0; length -= 8) {

            if (length >= 8) {

                c2l(in, sin0);

                c2l(in, sin1);

            } else

                c2ln(in, sin0, sin1, length);

            tin[0] = sin0 ^ xor0;

            tin[1] = sin1 ^ xor1;

            DES_encrypt1((DES_LONG *)tin, schedule, DES_ENCRYPT);

            tout0 = tin[0];

            tout1 = tin[1];

            xor0 = sin0 ^ tout0;

            xor1 = sin1 ^ tout1;

            l2c(tout0, out);

            l2c(tout1, out);

        }

    } else {

        c2l(iv, xor0);

        c2l(iv, xor1);

        for (; length > 0; length -= 8) {

            c2l(in, sin0);

            c2l(in, sin1);

            tin[0] = sin0;

            tin[1] = sin1;

            DES_encrypt1((DES_LONG *)tin, schedule, DES_DECRYPT);

            tout0 = tin[0] ^ xor0;

            tout1 = tin[1] ^ xor1;

            if (length >= 8) {

                l2c(tout0, out);

                l2c(tout1, out);

            } else

                l2cn(tout0, tout1, out, length);

            xor0 = tout0 ^ sin0;

            xor1 = tout1 ^ sin1;

        }

    }

    tin[0] = tin[1] = 0;

    sin0 = sin1 = xor0 = xor1 = tout0 = tout1 = 0;

}