/*

 * 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"

DES_LONG DES_cbc_cksum(const unsigned char *in, DES_cblock *output,

                       long length, DES_key_schedule *schedule,

                       const_DES_cblock *ivec)

{

    register DES_LONG tout0, tout1, tin0, tin1;

    register long l = length;

    DES_LONG tin[2];

    unsigned char *out = &(*output)[0];

    const unsigned char *iv = &(*ivec)[0];

    c2l(iv, tout0);

    c2l(iv, tout1);

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

        if (l >= 8) {

            c2l(in, tin0);

            c2l(in, tin1);

        } else

            c2ln(in, tin0, tin1, l);

        tin0 ^= tout0;

        tin[0] = tin0;

        tin1 ^= tout1;

        tin[1] = tin1;

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

        tout0 = tin[0];

        tout1 = tin[1];

    }

    if (out != NULL) {

        l2c(tout0, out);

        l2c(tout1, out);

    }

    tout0 = tin0 = tin1 = tin[0] = tin[1] = 0;

    /*

     * Transform the data in tout1 so that it will match the return value

     * that the MIT Kerberos mit_des_cbc_cksum API returns.

     */

    tout1 = ((tout1 >> 24L) & 0x000000FF)

        | ((tout1 >> 8L) & 0x0000FF00)

        | ((tout1 << 8L) & 0x00FF0000)

        | ((tout1 << 24L) & 0xFF000000);

    return tout1;

}