de.openflorian.crypt.provider.XorCipher.java Source code

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Here is the source code for de.openflorian.crypt.provider.XorCipher.java

Source

package de.openflorian.crypt.provider;

/*
 * This file is part of Openflorian.
 * 
 * Copyright (C) 2015  Bastian Kraus
 * 
 * Openflorian is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version)
 *     
 * Openflorian is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *     
 * You should have received a copy of the GNU General Public License
 * along with Openflorian.  If not, see <http://www.gnu.org/licenses/>.
 */

import java.io.UnsupportedEncodingException;
import java.security.GeneralSecurityException;

import org.apache.commons.codec.binary.Base64;

import de.openflorian.util.StringUtils;

/**
 * Classical XOR Cipher
 * 
 * @author Bastian Kraus <bofh@k-hive.de>
 */
public class XorCipher extends AbstractCipher {

    public XorCipher(String key) {
        super(key);
    }

    @Override
    public String encrypt(String plain) throws GeneralSecurityException {
        if (StringUtils.isEmpty(plain))
            throw new IllegalArgumentException("String AND Key may not be empty.");
        if (StringUtils.isEmpty(key))
            throw new IllegalStateException("Xor cipher key is not set.");

        char[] keychars = key.toCharArray();
        char[] targetchars = plain.toCharArray();

        int keycharsLength = keychars.length, targetcharsLength = targetchars.length;

        char[] newtarget = new char[targetcharsLength];

        for (int i = 0; i < targetcharsLength; i++)
            newtarget[i] = (char) (targetchars[i] ^ keychars[i % keycharsLength]);

        keychars = null;
        targetchars = null;

        try {
            return new String(new Base64().encode(new String(newtarget).getBytes("UTF-8")));
        } catch (UnsupportedEncodingException e) {
            throw new GeneralSecurityException(e);
        }
    }

    @Override
    public String decrypt(String target) throws GeneralSecurityException {
        if (StringUtils.isEmpty(target))
            throw new IllegalArgumentException("String AND Key may not be empty.");
        if (StringUtils.isEmpty(key))
            throw new IllegalStateException("Xor cipher key is not set.");

        char[] keychars = key.toCharArray();
        char[] targetchars = new String(Base64.decodeBase64(target.getBytes())).toCharArray();

        int keycharsLength = keychars.length, targetcharsLength = targetchars.length;

        char[] newtarget = new char[targetcharsLength];

        for (int i = 0; i < targetcharsLength; i++)
            newtarget[i] = (char) (targetchars[i] ^ keychars[i % keycharsLength]);

        keychars = null;
        targetchars = null;

        return new String(newtarget);
    }

}