/*

 * Copyright 1995-2016 The OpenSSL Project Authors. All Rights Reserved.

 *

 * Licensed under the OpenSSL license (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

 */

/*

 * From "Message Authentication" R.R. Jueneman, S.M. Matyas, C.H. Meyer IEEE

 * Communications Magazine Sept 1985 Vol. 23 No. 9 p 29-40 This module in

 * only based on the code in this paper and is almost definitely not the same

 * as the MIT implementation.

 */

#include "des_local.h"

#define Q_B0(a) (((DES_LONG)(a)))

#define Q_B1(a) (((DES_LONG)(a))<<8)

#define Q_B2(a) (((DES_LONG)(a))<<16)

#define Q_B3(a) (((DES_LONG)(a))<<24)

/* used to scramble things a bit */

/* Got the value MIT uses via brute force :-) 2/10/90 eay */

#define NOISE   ((DES_LONG)83653421L)

DES_LONG DES_quad_cksum(const unsigned char *input, DES_cblock output[],

                        long length, int out_count, DES_cblock *seed)

{

    DES_LONG z0, z1, t0, t1;

    int i;

    long l;

    const unsigned char *cp;

    DES_LONG *lp;

    if (out_count < 1)

        out_count = 1;

    lp = (DES_LONG *)&(output[0])[0];

    z0 = Q_B0((*seed)[0]) | Q_B1((*seed)[1]) | Q_B2((*seed)[2]) |

        Q_B3((*seed)[3]);

    z1 = Q_B0((*seed)[4]) | Q_B1((*seed)[5]) | Q_B2((*seed)[6]) |

        Q_B3((*seed)[7]);

    for (i = 0; ((i < 4) && (i < out_count)); i++) {

        cp = input;

        l = length;

        while (l > 0) {

            if (l > 1) {

                t0 = (DES_LONG)(*(cp++));

                t0 |= (DES_LONG)Q_B1(*(cp++));

                l--;

            } else

                t0 = (DES_LONG)(*(cp++));

            l--;

            /* add */

            t0 += z0;

            t0 &= 0xffffffffL;

            t1 = z1;

            /* square, well sort of square */

            z0 = ((((t0 * t0) & 0xffffffffL) + ((t1 * t1) & 0xffffffffL))

                  & 0xffffffffL) % 0x7fffffffL;

            z1 = ((t0 * ((t1 + NOISE) & 0xffffffffL)) & 0xffffffffL) %

                0x7fffffffL;

        }

        if (lp != NULL) {

            /*

             * The MIT library assumes that the checksum is composed of

             * 2*out_count 32 bit ints

             */

            *lp++ = z0;

            *lp++ = z1;

        }

    }

    return z0;

}