/* $OpenBSD: rc2.c,v 1.1 2025/05/25 05:29:54 jsing Exp $ */
/* 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_local.h"

static const unsigned char key_table[256]={
        0xd9,0x78,0xf9,0xc4,0x19,0xdd,0xb5,0xed,0x28,0xe9,0xfd,0x79,
        0x4a,0xa0,0xd8,0x9d,0xc6,0x7e,0x37,0x83,0x2b,0x76,0x53,0x8e,
        0x62,0x4c,0x64,0x88,0x44,0x8b,0xfb,0xa2,0x17,0x9a,0x59,0xf5,
        0x87,0xb3,0x4f,0x13,0x61,0x45,0x6d,0x8d,0x09,0x81,0x7d,0x32,
        0xbd,0x8f,0x40,0xeb,0x86,0xb7,0x7b,0x0b,0xf0,0x95,0x21,0x22,
        0x5c,0x6b,0x4e,0x82,0x54,0xd6,0x65,0x93,0xce,0x60,0xb2,0x1c,
        0x73,0x56,0xc0,0x14,0xa7,0x8c,0xf1,0xdc,0x12,0x75,0xca,0x1f,
        0x3b,0xbe,0xe4,0xd1,0x42,0x3d,0xd4,0x30,0xa3,0x3c,0xb6,0x26,
        0x6f,0xbf,0x0e,0xda,0x46,0x69,0x07,0x57,0x27,0xf2,0x1d,0x9b,
        0xbc,0x94,0x43,0x03,0xf8,0x11,0xc7,0xf6,0x90,0xef,0x3e,0xe7,
        0x06,0xc3,0xd5,0x2f,0xc8,0x66,0x1e,0xd7,0x08,0xe8,0xea,0xde,
        0x80,0x52,0xee,0xf7,0x84,0xaa,0x72,0xac,0x35,0x4d,0x6a,0x2a,
        0x96,0x1a,0xd2,0x71,0x5a,0x15,0x49,0x74,0x4b,0x9f,0xd0,0x5e,
        0x04,0x18,0xa4,0xec,0xc2,0xe0,0x41,0x6e,0x0f,0x51,0xcb,0xcc,
        0x24,0x91,0xaf,0x50,0xa1,0xf4,0x70,0x39,0x99,0x7c,0x3a,0x85,
        0x23,0xb8,0xb4,0x7a,0xfc,0x02,0x36,0x5b,0x25,0x55,0x97,0x31,
        0x2d,0x5d,0xfa,0x98,0xe3,0x8a,0x92,0xae,0x05,0xdf,0x29,0x10,
        0x67,0x6c,0xba,0xc9,0xd3,0x00,0xe6,0xcf,0xe1,0x9e,0xa8,0x2c,
        0x63,0x16,0x01,0x3f,0x58,0xe2,0x89,0xa9,0x0d,0x38,0x34,0x1b,
        0xab,0x33,0xff,0xb0,0xbb,0x48,0x0c,0x5f,0xb9,0xb1,0xcd,0x2e,
        0xc5,0xf3,0xdb,0x47,0xe5,0xa5,0x9c,0x77,0x0a,0xa6,0x20,0x68,
        0xfe,0x7f,0xc1,0xad,
        };

/* It has come to my attention that there are 2 versions of the RC2
 * key schedule.  One which is normal, and anther which has a hook to
 * use a reduced key length.
 * BSAFE uses the 'retarded' version.  What I previously shipped is
 * the same as specifying 1024 for the 'bits' parameter.  Bsafe uses
 * a version where the bits parameter is the same as len*8 */
void
RC2_set_key(RC2_KEY *key, int len, const unsigned char *data, int bits)
{
        int i, j;
        unsigned char *k;
        RC2_INT *ki;
        unsigned int c, d;

        k = (unsigned char *)&(key->data[0]);
        *k = 0; /* for if there is a zero length key */

        if (len > 128)
                len = 128;
        if (bits <= 0)
                bits = 1024;
        if (bits > 1024)
                bits = 1024;

        for (i = 0; i < len; i++)
                k[i] = data[i];

        /* expand table */
        d = k[len - 1];
        j = 0;
        for (i = len; i < 128; i++, j++)
        {
                d = key_table[(k[j] + d) & 0xff];
                k[i] = d;
        }

        /* hmm.... key reduction to 'bits' bits */

        j = (bits + 7) >> 3;
        i = 128 - j;
        c = (0xff >> (-bits & 0x07));

        d = key_table[k[i] & c];
        k[i] = d;
        while (i--) {
                d = key_table[k[i + j] ^ d];
                k[i] = d;
        }

        /* copy from bytes into RC2_INT's */
        ki = &(key->data[63]);
        for (i = 127; i >= 0; i -= 2)
                *(ki--) = ((k[i] << 8)|k[i - 1]) & 0xffff;
}
LCRYPTO_ALIAS(RC2_set_key);

void
RC2_encrypt(unsigned long *d, RC2_KEY *key)
{
        int i, n;
        RC2_INT *p0, *p1;
        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);
}
LCRYPTO_ALIAS(RC2_encrypt);

void
RC2_decrypt(unsigned long *d, RC2_KEY *key)
{
        int i, n;
        RC2_INT *p0, *p1;
        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);
}
LCRYPTO_ALIAS(RC2_decrypt);

void
RC2_cbc_encrypt(const unsigned char *in, unsigned char *out, long length,
    RC2_KEY *ks, unsigned char *iv, int encrypt)
{
        unsigned long tin0, tin1;
        unsigned long tout0, tout1, xor0, xor1;
        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;
}
LCRYPTO_ALIAS(RC2_cbc_encrypt);

/* The input and output encrypted as though 64bit cfb mode is being
 * used.  The extra state information to record how much of the
 * 64bit block we have used is contained in *num;
 */
void
RC2_cfb64_encrypt(const unsigned char *in, unsigned char *out,
    long length, RC2_KEY *schedule, unsigned char *ivec,
    int *num, int encrypt)
{
        unsigned long v0, v1, t;
        int n = *num;
        long l = length;
        unsigned long ti[2];
        unsigned char *iv, c, cc;

        iv = (unsigned char *)ivec;
        if (encrypt) {
                while (l--) {
                        if (n == 0) {
                                c2l(iv, v0);
                                ti[0] = v0;
                                c2l(iv, v1);
                                ti[1] = v1;
                                RC2_encrypt((unsigned long *)ti, schedule);
                                iv = (unsigned char *)ivec;
                                t = ti[0];
                                l2c(t, iv);
                                t = ti[1];
                                l2c(t, iv);
                                iv = (unsigned char *)ivec;
                        }
                        c = *(in++) ^ iv[n];
                        *(out++) = c;
                        iv[n] = c;
                        n = (n + 1) & 0x07;
                }
        } else {
                while (l--) {
                        if (n == 0) {
                                c2l(iv, v0);
                                ti[0] = v0;
                                c2l(iv, v1);
                                ti[1] = v1;
                                RC2_encrypt((unsigned long *)ti, schedule);
                                iv = (unsigned char *)ivec;
                                t = ti[0];
                                l2c(t, iv);
                                t = ti[1];
                                l2c(t, iv);
                                iv = (unsigned char *)ivec;
                        }
                        cc = *(in++);
                        c = iv[n];
                        iv[n] = cc;
                        *(out++) = c ^ cc;
                        n = (n + 1) & 0x07;
                }
        }
        v0 = v1 = ti[0] = ti[1] = t = c = cc = 0;
        *num = n;
}
LCRYPTO_ALIAS(RC2_cfb64_encrypt);

/* RC2 as implemented frm a posting from
 * Newsgroups: sci.crypt
 * Sender: pgut01@cs.auckland.ac.nz (Peter Gutmann)
 * Subject: Specification for Ron Rivests Cipher No.2
 * Message-ID: <4fk39f$f70@net.auckland.ac.nz>
 * Date: 11 Feb 1996 06:45:03 GMT
 */
void
RC2_ecb_encrypt(const unsigned char *in, unsigned char *out, RC2_KEY *ks,
    int encrypt)
{
        unsigned long l, d[2];

        c2l(in, l);
        d[0] = l;
        c2l(in, l);
        d[1] = l;
        if (encrypt)
                RC2_encrypt(d, ks);
        else
                RC2_decrypt(d, ks);
        l = d[0];
        l2c(l, out);
        l = d[1];
        l2c(l, out);
        l = d[0] = d[1] = 0;
}
LCRYPTO_ALIAS(RC2_ecb_encrypt);

/* The input and output encrypted as though 64bit ofb mode is being
 * used.  The extra state information to record how much of the
 * 64bit block we have used is contained in *num;
 */
void
RC2_ofb64_encrypt(const unsigned char *in, unsigned char *out,
    long length, RC2_KEY *schedule, unsigned char *ivec,
    int *num)
{
        unsigned long v0, v1, t;
        int n = *num;
        long l = length;
        unsigned char d[8];
        char *dp;
        unsigned long ti[2];
        unsigned char *iv;
        int save = 0;

        iv = (unsigned char *)ivec;
        c2l(iv, v0);
        c2l(iv, v1);
        ti[0] = v0;
        ti[1] = v1;
        dp = (char *)d;
        l2c(v0, dp);
        l2c(v1, dp);
        while (l--) {
                if (n == 0) {
                        RC2_encrypt((unsigned long *)ti, schedule);
                        dp = (char *)d;
                        t = ti[0];
                        l2c(t, dp);
                        t = ti[1];
                        l2c(t, dp);
                        save++;
                }
                *(out++) = *(in++) ^ d[n];
                n = (n + 1) & 0x07;
        }
        if (save) {
                v0 = ti[0];
                v1 = ti[1];
                iv = (unsigned char *)ivec;
                l2c(v0, iv);
                l2c(v1, iv);
        }
        t = v0 = v1 = ti[0] = ti[1] = 0;
        *num = n;
}
LCRYPTO_ALIAS(RC2_ofb64_encrypt);