rc5_enc.c

/*
 * Copyright 1995-2016 The OpenSSL Project Authors. All Rights Reserved.
 *
 * Licensed under the OpenSSL license (the "License").  You may not use
 * this file except in compliance with the License.  You can obtain a copy
 * in the file LICENSE in the source distribution or at
 * https://www.openssl.org/source/license.html
 */

#include <stdio.h>
#include <openssl/rc5.h>
#include "rc5_local.h"

void RC5_32_cbc_encrypt(const unsigned char *in, unsigned char *out,
                        long length, RC5_32_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;
            RC5_32_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;
            RC5_32_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;
            RC5_32_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;
            RC5_32_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 RC5_32_encrypt(unsigned long *d, RC5_32_KEY *key)
{
    RC5_32_INT a, b, *s;

    s = key->data;

    a = d[0] + s[0];
    b = d[1] + s[1];
    E_RC5_32(a, b, s, 2);
    E_RC5_32(a, b, s, 4);
    E_RC5_32(a, b, s, 6);
    E_RC5_32(a, b, s, 8);
    E_RC5_32(a, b, s, 10);
    E_RC5_32(a, b, s, 12);
    E_RC5_32(a, b, s, 14);
    E_RC5_32(a, b, s, 16);
    if (key->rounds == 12) {
        E_RC5_32(a, b, s, 18);
        E_RC5_32(a, b, s, 20);
        E_RC5_32(a, b, s, 22);
        E_RC5_32(a, b, s, 24);
    } else if (key->rounds == 16) {
        /* Do a full expansion to avoid a jump */
        E_RC5_32(a, b, s, 18);
        E_RC5_32(a, b, s, 20);
        E_RC5_32(a, b, s, 22);
        E_RC5_32(a, b, s, 24);
        E_RC5_32(a, b, s, 26);
        E_RC5_32(a, b, s, 28);
        E_RC5_32(a, b, s, 30);
        E_RC5_32(a, b, s, 32);
    }
    d[0] = a;
    d[1] = b;
}

void RC5_32_decrypt(unsigned long *d, RC5_32_KEY *key)
{
    RC5_32_INT a, b, *s;

    s = key->data;

    a = d[0];
    b = d[1];
    if (key->rounds == 16) {
        D_RC5_32(a, b, s, 32);
        D_RC5_32(a, b, s, 30);
        D_RC5_32(a, b, s, 28);
        D_RC5_32(a, b, s, 26);
        /* Do a full expansion to avoid a jump */
        D_RC5_32(a, b, s, 24);
        D_RC5_32(a, b, s, 22);
        D_RC5_32(a, b, s, 20);
        D_RC5_32(a, b, s, 18);
    } else if (key->rounds == 12) {
        D_RC5_32(a, b, s, 24);
        D_RC5_32(a, b, s, 22);
        D_RC5_32(a, b, s, 20);
        D_RC5_32(a, b, s, 18);
    }
    D_RC5_32(a, b, s, 16);
    D_RC5_32(a, b, s, 14);
    D_RC5_32(a, b, s, 12);
    D_RC5_32(a, b, s, 10);
    D_RC5_32(a, b, s, 8);
    D_RC5_32(a, b, s, 6);
    D_RC5_32(a, b, s, 4);
    D_RC5_32(a, b, s, 2);
    d[0] = a - s[0];
    d[1] = b - s[1];
}