/* $OpenBSD: idea.c,v 1.1 2024/03/29 05:23:50 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/idea.h>
#include "idea_local.h"

void
idea_cbc_encrypt(const unsigned char *in, unsigned char *out, long length,
    IDEA_KEY_SCHEDULE *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) {
                n2l(iv, tout0);
                n2l(iv, tout1);
                iv -= 8;
                for (l -= 8; l >= 0; l -= 8)
                {
                        n2l(in, tin0);
                        n2l(in, tin1);
                        tin0 ^= tout0;
                        tin1 ^= tout1;
                        tin[0] = tin0;
                        tin[1] = tin1;
                        idea_encrypt(tin, ks);
                        tout0 = tin[0];
                        l2n(tout0, out);
                        tout1 = tin[1];
                        l2n(tout1, out);
                }
                if (l != -8) {
                        n2ln(in, tin0, tin1, l + 8);
                        tin0 ^= tout0;
                        tin1 ^= tout1;
                        tin[0] = tin0;
                        tin[1] = tin1;
                        idea_encrypt(tin, ks);
                        tout0 = tin[0];
                        l2n(tout0, out);
                        tout1 = tin[1];
                        l2n(tout1, out);
                }
                l2n(tout0, iv);
                l2n(tout1, iv);
        } else {
                n2l(iv, xor0);
                n2l(iv, xor1);
                iv -= 8;
                for (l -= 8; l >= 0; l -= 8)
                {
                        n2l(in, tin0);
                        tin[0] = tin0;
                        n2l(in, tin1);
                        tin[1] = tin1;
                        idea_encrypt(tin, ks);
                        tout0 = tin[0] ^ xor0;
                        tout1 = tin[1] ^ xor1;
                        l2n(tout0, out);
                        l2n(tout1, out);
                        xor0 = tin0;
                        xor1 = tin1;
                }
                if (l != -8) {
                        n2l(in, tin0);
                        tin[0] = tin0;
                        n2l(in, tin1);
                        tin[1] = tin1;
                        idea_encrypt(tin, ks);
                        tout0 = tin[0] ^ xor0;
                        tout1 = tin[1] ^ xor1;
                        l2nn(tout0, tout1, out, l + 8);
                        xor0 = tin0;
                        xor1 = tin1;
                }
                l2n(xor0, iv);
                l2n(xor1, iv);
        }
        tin0 = tin1 = tout0 = tout1 = xor0 = xor1 = 0;
        tin[0] = tin[1] = 0;
}
LCRYPTO_ALIAS(idea_cbc_encrypt);

void
idea_encrypt(unsigned long *d, IDEA_KEY_SCHEDULE *key)
{
        IDEA_INT *p;
        unsigned long x1, x2, x3, x4, t0, t1, ul;

        x2 = d[0];
        x1 = (x2 >> 16);
        x4 = d[1];
        x3 = (x4 >> 16);

        p = &(key->data[0][0]);

        E_IDEA(0);
        E_IDEA(1);
        E_IDEA(2);
        E_IDEA(3);
        E_IDEA(4);
        E_IDEA(5);
        E_IDEA(6);
        E_IDEA(7);

        x1 &= 0xffff;
        idea_mul(x1, x1, *p, ul);
        p++;

        t0 = x3 + *(p++);
        t1 = x2 + *(p++);

        x4 &= 0xffff;
        idea_mul(x4, x4, *p, ul);

        d[0] = (t0 & 0xffff)|((x1 & 0xffff) << 16);
        d[1] = (x4 & 0xffff)|((t1 & 0xffff) << 16);
}
LCRYPTO_ALIAS(idea_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
idea_cfb64_encrypt(const unsigned char *in, unsigned char *out,
    long length, IDEA_KEY_SCHEDULE *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) {
                                n2l(iv, v0);
                                ti[0] = v0;
                                n2l(iv, v1);
                                ti[1] = v1;
                                idea_encrypt((unsigned long *)ti, schedule);
                                iv = (unsigned char *)ivec;
                                t = ti[0];
                                l2n(t, iv);
                                t = ti[1];
                                l2n(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) {
                                n2l(iv, v0);
                                ti[0] = v0;
                                n2l(iv, v1);
                                ti[1] = v1;
                                idea_encrypt((unsigned long *)ti, schedule);
                                iv = (unsigned char *)ivec;
                                t = ti[0];
                                l2n(t, iv);
                                t = ti[1];
                                l2n(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(idea_cfb64_encrypt);

void
idea_ecb_encrypt(const unsigned char *in, unsigned char *out,
    IDEA_KEY_SCHEDULE *ks)
{
        unsigned long l0, l1, d[2];

        n2l(in, l0);
        d[0] = l0;
        n2l(in, l1);
        d[1] = l1;
        idea_encrypt(d, ks);
        l0 = d[0];
        l2n(l0, out);
        l1 = d[1];
        l2n(l1, out);
        l0 = l1 = d[0] = d[1] = 0;
}
LCRYPTO_ALIAS(idea_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
idea_ofb64_encrypt(const unsigned char *in, unsigned char *out,
    long length, IDEA_KEY_SCHEDULE *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;
        n2l(iv, v0);
        n2l(iv, v1);
        ti[0] = v0;
        ti[1] = v1;
        dp = (char *)d;
        l2n(v0, dp);
        l2n(v1, dp);
        while (l--) {
                if (n == 0) {
                        idea_encrypt((unsigned long *)ti, schedule);
                        dp = (char *)d;
                        t = ti[0];
                        l2n(t, dp);
                        t = ti[1];
                        l2n(t, dp);
                        save++;
                }
                *(out++) = *(in++) ^ d[n];
                n = (n + 1) & 0x07;
        }
        if (save) {
                v0 = ti[0];
                v1 = ti[1];
                iv = (unsigned char *)ivec;
                l2n(v0, iv);
                l2n(v1, iv);
        }
        t = v0 = v1 = ti[0] = ti[1] = 0;
        *num = n;
}
LCRYPTO_ALIAS(idea_ofb64_encrypt);

/* taken directly from the 'paper' I'll have a look at it later */
static IDEA_INT
inverse(unsigned int xin)
{
        long n1, n2, q, r, b1, b2, t;

        if (xin == 0)
                b2 = 0;
        else {
                n1 = 0x10001;
                n2 = xin;
                b2 = 1;
                b1 = 0;

                do {
                        r = (n1 % n2);
                        q = (n1 - r)/n2;
                        if (r == 0) {
                                if (b2 < 0)
                                        b2 = 0x10001 + b2;
                        } else {
                                n1 = n2;
                                n2 = r;
                                t = b2;
                                b2 = b1 - q*b2;
                                b1 = t;
                        }
                } while (r != 0);
        }
        return ((IDEA_INT)b2);
}

void
idea_set_encrypt_key(const unsigned char *key, IDEA_KEY_SCHEDULE *ks)
{
        int i;
        IDEA_INT *kt, *kf, r0, r1, r2;

        kt = &(ks->data[0][0]);
        n2s(key, kt[0]);
        n2s(key, kt[1]);
        n2s(key, kt[2]);
        n2s(key, kt[3]);
        n2s(key, kt[4]);
        n2s(key, kt[5]);
        n2s(key, kt[6]);
        n2s(key, kt[7]);

        kf = kt;
        kt += 8;
        for (i = 0; i < 6; i++)
        {
                r2 = kf[1];
                r1 = kf[2];
                *(kt++) = ((r2 << 9) | (r1 >> 7)) & 0xffff;
                r0 = kf[3];
                *(kt++) = ((r1 << 9) | (r0 >> 7)) & 0xffff;
                r1 = kf[4];
                *(kt++) = ((r0 << 9) | (r1 >> 7)) & 0xffff;
                r0 = kf[5];
                *(kt++) = ((r1 << 9) | (r0 >> 7)) & 0xffff;
                r1 = kf[6];
                *(kt++) = ((r0 << 9) | (r1 >> 7)) & 0xffff;
                r0 = kf[7];
                *(kt++) = ((r1 << 9) | (r0 >> 7)) & 0xffff;
                r1 = kf[0];
                if (i >= 5)
                        break;
                *(kt++) = ((r0 << 9) | (r1 >> 7)) & 0xffff;
                *(kt++) = ((r1 << 9) | (r2 >> 7)) & 0xffff;
                kf += 8;
        }
}
LCRYPTO_ALIAS(idea_set_encrypt_key);

void
idea_set_decrypt_key(IDEA_KEY_SCHEDULE *ek, IDEA_KEY_SCHEDULE *dk)
{
        int r;
        IDEA_INT *fp, *tp, t;

        tp = &(dk->data[0][0]);
        fp = &(ek->data[8][0]);
        for (r = 0; r < 9; r++)
        {
                *(tp++) = inverse(fp[0]);
                *(tp++) = ((int)(0x10000L - fp[2]) & 0xffff);
                *(tp++) = ((int)(0x10000L - fp[1]) & 0xffff);
                *(tp++) = inverse(fp[3]);
                if (r == 8)
                        break;
                fp -= 6;
                *(tp++) = fp[4];
                *(tp++) = fp[5];
        }

        tp = &(dk->data[0][0]);
        t = tp[1];
        tp[1] = tp[2];
        tp[2] = t;

        t = tp[49];
        tp[49] = tp[50];
        tp[50] = t;
}
LCRYPTO_ALIAS(idea_set_decrypt_key);