1/*
2 * Copyright 1995-2020 The OpenSSL Project Authors. All Rights Reserved.
3 *
4 * Licensed under the Apache License 2.0 (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
17/*
18 * DES low level APIs are deprecated for public use, but still ok for internal
19 * use.
20 */
21#include "internal/deprecated.h"
22
23#include "des_local.h"
24
25#define Q_B0(a) (((DES_LONG)(a)))
26#define Q_B1(a) (((DES_LONG)(a))<<8)
27#define Q_B2(a) (((DES_LONG)(a))<<16)
28#define Q_B3(a) (((DES_LONG)(a))<<24)
29
30/* used to scramble things a bit */
31/* Got the value MIT uses via brute force :-) 2/10/90 eay */
32#define NOISE   ((DES_LONG)83653421L)
33
34DES_LONG DES_quad_cksum(const unsigned char *input, DES_cblock output[],
35                        long length, int out_count, DES_cblock *seed)
36{
37    DES_LONG z0, z1, t0, t1;
38    int i;
39    long l;
40    const unsigned char *cp;
41    DES_LONG *lp;
42
43    if (out_count < 1)
44        out_count = 1;
45    lp = (DES_LONG *)&(output[0])[0];
46
47    z0 = Q_B0((*seed)[0]) | Q_B1((*seed)[1]) | Q_B2((*seed)[2]) |
48        Q_B3((*seed)[3]);
49    z1 = Q_B0((*seed)[4]) | Q_B1((*seed)[5]) | Q_B2((*seed)[6]) |
50        Q_B3((*seed)[7]);
51
52    for (i = 0; ((i < 4) && (i < out_count)); i++) {
53        cp = input;
54        l = length;
55        while (l > 0) {
56            if (l > 1) {
57                t0 = (DES_LONG)(*(cp++));
58                t0 |= (DES_LONG)Q_B1(*(cp++));
59                l--;
60            } else
61                t0 = (DES_LONG)(*(cp++));
62            l--;
63            /* add */
64            t0 += z0;
65            t0 &= 0xffffffffL;
66            t1 = z1;
67            /* square, well sort of square */
68            z0 = ((((t0 * t0) & 0xffffffffL) + ((t1 * t1) & 0xffffffffL))
69                  & 0xffffffffL) % 0x7fffffffL;
70            z1 = ((t0 * ((t1 + NOISE) & 0xffffffffL)) & 0xffffffffL) %
71                0x7fffffffL;
72        }
73        if (lp != NULL) {
74            /*
75             * The MIT library assumes that the checksum is composed of
76             * 2*out_count 32 bit ints
77             */
78            *lp++ = z0;
79            *lp++ = z1;
80        }
81    }
82    return z0;
83}
84