source-engine/thirdparty/openssl/crypto/rc2/rc2_cbc.c

/* crypto/rc2/rc2_cbc.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/rc2.h>
#include "rc2_locl.h"

void RC2_cbc_encrypt(const unsigned char *in, unsigned char *out, long length,
                     RC2_KEY *ks, unsigned char *iv, int encrypt)
{
    register unsigned long tin0, tin1;
    register unsigned long tout0, tout1, xor0, xor1;
    register long l = length;
    unsigned long tin[2];

    if (encrypt) {
        c2l(iv, tout0);
        c2l(iv, tout1);
        iv -= 8;
        for (l -= 8; l >= 0; l -= 8) {
            c2l(in, tin0);
            c2l(in, tin1);
            tin0 ^= tout0;
            tin1 ^= tout1;
            tin[0] = tin0;
            tin[1] = tin1;
            RC2_encrypt(tin, ks);
            tout0 = tin[0];
            l2c(tout0, out);
            tout1 = tin[1];
            l2c(tout1, out);
        }
        if (l != -8) {
            c2ln(in, tin0, tin1, l + 8);
            tin0 ^= tout0;
            tin1 ^= tout1;
            tin[0] = tin0;
            tin[1] = tin1;
            RC2_encrypt(tin, ks);
            tout0 = tin[0];
            l2c(tout0, out);
            tout1 = tin[1];
            l2c(tout1, out);
        }
        l2c(tout0, iv);
        l2c(tout1, iv);
    } else {
        c2l(iv, xor0);
        c2l(iv, xor1);
        iv -= 8;
        for (l -= 8; l >= 0; l -= 8) {
            c2l(in, tin0);
            tin[0] = tin0;
            c2l(in, tin1);
            tin[1] = tin1;
            RC2_decrypt(tin, ks);
            tout0 = tin[0] ^ xor0;
            tout1 = tin[1] ^ xor1;
            l2c(tout0, out);
            l2c(tout1, out);
            xor0 = tin0;
            xor1 = tin1;
        }
        if (l != -8) {
            c2l(in, tin0);
            tin[0] = tin0;
            c2l(in, tin1);
            tin[1] = tin1;
            RC2_decrypt(tin, ks);
            tout0 = tin[0] ^ xor0;
            tout1 = tin[1] ^ xor1;
            l2cn(tout0, tout1, out, l + 8);
            xor0 = tin0;
            xor1 = tin1;
        }
        l2c(xor0, iv);
        l2c(xor1, iv);
    }
    tin0 = tin1 = tout0 = tout1 = xor0 = xor1 = 0;
    tin[0] = tin[1] = 0;
}

void RC2_encrypt(unsigned long *d, RC2_KEY *key)
{
    int i, n;
    register RC2_INT *p0, *p1;
    register RC2_INT x0, x1, x2, x3, t;
    unsigned long l;

    l = d[0];
    x0 = (RC2_INT) l & 0xffff;
    x1 = (RC2_INT) (l >> 16L);
    l = d[1];
    x2 = (RC2_INT) l & 0xffff;
    x3 = (RC2_INT) (l >> 16L);

    n = 3;
    i = 5;

    p0 = p1 = &(key->data[0]);
    for (;;) {
        t = (x0 + (x1 & ~x3) + (x2 & x3) + *(p0++)) & 0xffff;
        x0 = (t << 1) | (t >> 15);
        t = (x1 + (x2 & ~x0) + (x3 & x0) + *(p0++)) & 0xffff;
        x1 = (t << 2) | (t >> 14);
        t = (x2 + (x3 & ~x1) + (x0 & x1) + *(p0++)) & 0xffff;
        x2 = (t << 3) | (t >> 13);
        t = (x3 + (x0 & ~x2) + (x1 & x2) + *(p0++)) & 0xffff;
        x3 = (t << 5) | (t >> 11);

        if (--i == 0) {
            if (--n == 0)
                break;
            i = (n == 2) ? 6 : 5;

            x0 += p1[x3 & 0x3f];
            x1 += p1[x0 & 0x3f];
            x2 += p1[x1 & 0x3f];
            x3 += p1[x2 & 0x3f];
        }
    }

    d[0] =
        (unsigned long)(x0 & 0xffff) | ((unsigned long)(x1 & 0xffff) << 16L);
    d[1] =
        (unsigned long)(x2 & 0xffff) | ((unsigned long)(x3 & 0xffff) << 16L);
}

void RC2_decrypt(unsigned long *d, RC2_KEY *key)
{
    int i, n;
    register RC2_INT *p0, *p1;
    register RC2_INT x0, x1, x2, x3, t;
    unsigned long l;

    l = d[0];
    x0 = (RC2_INT) l & 0xffff;
    x1 = (RC2_INT) (l >> 16L);
    l = d[1];
    x2 = (RC2_INT) l & 0xffff;
    x3 = (RC2_INT) (l >> 16L);

    n = 3;
    i = 5;

    p0 = &(key->data[63]);
    p1 = &(key->data[0]);
    for (;;) {
        t = ((x3 << 11) | (x3 >> 5)) & 0xffff;
        x3 = (t - (x0 & ~x2) - (x1 & x2) - *(p0--)) & 0xffff;
        t = ((x2 << 13) | (x2 >> 3)) & 0xffff;
        x2 = (t - (x3 & ~x1) - (x0 & x1) - *(p0--)) & 0xffff;
        t = ((x1 << 14) | (x1 >> 2)) & 0xffff;
        x1 = (t - (x2 & ~x0) - (x3 & x0) - *(p0--)) & 0xffff;
        t = ((x0 << 15) | (x0 >> 1)) & 0xffff;
        x0 = (t - (x1 & ~x3) - (x2 & x3) - *(p0--)) & 0xffff;

        if (--i == 0) {
            if (--n == 0)
                break;
            i = (n == 2) ? 6 : 5;

            x3 = (x3 - p1[x2 & 0x3f]) & 0xffff;
            x2 = (x2 - p1[x1 & 0x3f]) & 0xffff;
            x1 = (x1 - p1[x0 & 0x3f]) & 0xffff;
            x0 = (x0 - p1[x3 & 0x3f]) & 0xffff;
        }
    }

    d[0] =
        (unsigned long)(x0 & 0xffff) | ((unsigned long)(x1 & 0xffff) << 16L);
    d[1] =
        (unsigned long)(x2 & 0xffff) | ((unsigned long)(x3 & 0xffff) << 16L);
}