qud_cksm.c

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/* crypto/des/qud_cksm.c */
/* Copyright (C) 1995-1998 Eric Young ([email protected])
 * All rights reserved.
 *
 * This package is an SSL implementation written
 * by Eric Young ([email protected]).
 * The implementation was written so as to conform with Netscapes SSL.
 * 
 * This library is free for commercial and non-commercial use as long as
 * the following conditions are aheared to.  The following conditions
 * apply to all code found in this distribution, be it the RC4, RSA,
 * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
 * included with this distribution is covered by the same copyright terms
 * except that the holder is Tim Hudson ([email protected]).
 * 
 * Copyright remains Eric Young's, and as such any Copyright notices in
 * the code are not to be removed.
 * If this package is used in a product, Eric Young should be given attribution
 * as the author of the parts of the library used.
 * This can be in the form of a textual message at program startup or
 * in documentation (online or textual) provided with the package.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *    "This product includes cryptographic software written by
 *     Eric Young ([email protected])"
 *    The word 'cryptographic' can be left out if the rouines from the library
 *    being used are not cryptographic related :-).
 * 4. If you include any Windows specific code (or a derivative thereof) from 
 *    the apps directory (application code) you must include an acknowledgement:
 *    "This product includes software written by Tim Hudson ([email protected])"
 * 
 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * 
 * The licence and distribution terms for any publically available version or
 * derivative of this code cannot be changed.  i.e. this code cannot simply be
 * copied and put under another distribution licence
 * [including the GNU Public Licence.]
 */

/* 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_locl.h"

/* bug fix for dos - 7/6/91 - Larry [email protected] */
#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;
#ifdef _CRAY
    struct lp_st { int a:32; int b:32; } *lp;
#else
    DES_LONG *lp;
#endif

    if (out_count < 1) out_count=1;
#ifdef _CRAY
    lp = (struct lp_st *) &(output[0])[0];
#else
    lp = (DES_LONG *) &(output[0])[0];
#endif

    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 */
#ifdef _CRAY
            (*lp).a = z0;
            (*lp).b = z1;
            lp++;
#else
            *lp++ = z0;
            *lp++ = z1;
#endif
            }
        }
    return(z0);
    }