rc5_skey.c

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/* crypto/rc5/rc5_skey.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.]
 */

#include <openssl/rc5.h>
#include "rc5_locl.h"

void RC5_32_set_key(RC5_32_KEY *key, int len, const unsigned char *data,
            int rounds)
    {
    RC5_32_INT L[64],l,ll,A,B,*S,k;
    int i,j,m,c,t,ii,jj;

    if (    (rounds != RC5_16_ROUNDS) &&
        (rounds != RC5_12_ROUNDS) &&
        (rounds != RC5_8_ROUNDS))
        rounds=RC5_16_ROUNDS;

    key->rounds=rounds;
    S= &(key->data[0]);
    j=0;
    for (i=0; i<=(len-8); i+=8)
        {
        c2l(data,l);
        L[j++]=l;
        c2l(data,l);
        L[j++]=l;
        }
    ii=len-i;
    if (ii)
        {
        k=len&0x07;
        c2ln(data,l,ll,k);
        L[j+0]=l;
        L[j+1]=ll;
        }

    c=(len+3)/4;
    t=(rounds+1)*2;
    S[0]=RC5_32_P;
    for (i=1; i<t; i++)
        S[i]=(S[i-1]+RC5_32_Q)&RC5_32_MASK;

    j=(t>c)?t:c;
    j*=3;
    ii=jj=0;
    A=B=0;
    for (i=0; i<j; i++)
        {
        k=(S[ii]+A+B)&RC5_32_MASK;
        A=S[ii]=ROTATE_l32(k,3);
        m=(int)(A+B);
        k=(L[jj]+A+B)&RC5_32_MASK;
        B=L[jj]=ROTATE_l32(k,m);
        if (++ii >= t) ii=0;
        if (++jj >= c) jj=0;
        }
    }