1/*
2 * Copyright 1995-2016 The OpenSSL Project Authors. All Rights Reserved.
3 *
4 * Licensed under the OpenSSL license (the "License").  You may not use
5 * this file except in compliance with the License.  You can obtain a copy
6 * in the file LICENSE in the source distribution or at
7 * https://www.openssl.org/source/license.html
8 */
9
10/*
11 * From "Message Authentication" R.R. Jueneman, S.M. Matyas, C.H. Meyer IEEE
12 * Communications Magazine Sept 1985 Vol. 23 No. 9 p 29-40 This module in
13 * only based on the code in this paper and is almost definitely not the same
14 * as the MIT implementation.
15 */
16#include "des_local.h"
17
18#define Q_B0(a) (((DES_LONG)(a)))
19#define Q_B1(a) (((DES_LONG)(a))<<8)
20#define Q_B2(a) (((DES_LONG)(a))<<16)
21#define Q_B3(a) (((DES_LONG)(a))<<24)
22
23/* used to scramble things a bit */
24/* Got the value MIT uses via brute force :-) 2/10/90 eay */
25#define NOISE   ((DES_LONG)83653421L)
26
27DES_LONG DES_quad_cksum(const unsigned char *input, DES_cblock output[],
28                        long length, int out_count, DES_cblock *seed)
29{
30    DES_LONG z0, z1, t0, t1;
31    int i;
32    long l;
33    const unsigned char *cp;
34    DES_LONG *lp;
35
36    if (out_count < 1)
37        out_count = 1;
38    lp = (DES_LONG *)&(output[0])[0];
39
40    z0 = Q_B0((*seed)[0]) | Q_B1((*seed)[1]) | Q_B2((*seed)[2]) |
41        Q_B3((*seed)[3]);
42    z1 = Q_B0((*seed)[4]) | Q_B1((*seed)[5]) | Q_B2((*seed)[6]) |
43        Q_B3((*seed)[7]);
44
45    for (i = 0; ((i < 4) && (i < out_count)); i++) {
46        cp = input;
47        l = length;
48        while (l > 0) {
49            if (l > 1) {
50                t0 = (DES_LONG)(*(cp++));
51                t0 |= (DES_LONG)Q_B1(*(cp++));
52                l--;
53            } else
54                t0 = (DES_LONG)(*(cp++));
55            l--;
56            /* add */
57            t0 += z0;
58            t0 &= 0xffffffffL;
59            t1 = z1;
60            /* square, well sort of square */
61            z0 = ((((t0 * t0) & 0xffffffffL) + ((t1 * t1) & 0xffffffffL))
62                  & 0xffffffffL) % 0x7fffffffL;
63            z1 = ((t0 * ((t1 + NOISE) & 0xffffffffL)) & 0xffffffffL) %
64                0x7fffffffL;
65        }
66        if (lp != NULL) {
67            /*
68             * The MIT library assumes that the checksum is composed of
69             * 2*out_count 32 bit ints
70             */
71            *lp++ = z0;
72            *lp++ = z1;
73        }
74    }
75    return z0;
76}
77