openssl/crypto/rc5/rc5_skey.c

/* crypto/rc5/rc5_skey.c */
/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
 * All rights reserved.
 *
 * This package is an SSL implementation written
 * by Eric Young (eay@cryptsoft.com).
 * 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 (tjh@cryptsoft.com).
 *
 * 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 (eay@cryptsoft.com)"
 *    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 (tjh@cryptsoft.com)"
 *
 * 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;
    }
}