com.rcythr.masq.util.AES.java Source code

Introduction

Here is the source code for com.rcythr.masq.util.AES.java

Source

/**   This file is part of Masq.
    
Masq 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.
    
Masq 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 Masq.  If not, see <http://www.gnu.org/licenses/>.
**/

package com.rcythr.masq.util;

import org.bouncycastle.crypto.BufferedBlockCipher;
import org.bouncycastle.crypto.CipherParameters;
import org.bouncycastle.crypto.InvalidCipherTextException;
import org.bouncycastle.crypto.engines.AESEngine;
import org.bouncycastle.crypto.paddings.PaddedBufferedBlockCipher;
import org.bouncycastle.crypto.paddings.ZeroBytePadding;
import org.bouncycastle.crypto.params.KeyParameter;

/**
 * Utility class used to encrypt/decrypt data
 * 
 * @author Richard Laughlin
 */
public class AES {

    /**
     * Designates the key size to use in bytes.
     * 
     * 16 bytes = 128 bits
     * 24 bytes = 192 bits
     * 32 bytes = 256 bits
     * 
     */
    public static final int AES_KEY_SIZE = 32;

    /**
     * Uses inputs to encrypt/decrypt based on the value of encrypt
     * @param forEncryption if true encrypt, if false decrypt
     * @param input the data to work with
     * @param key the key to use
     * @return the result
     * 
     * @throws InvalidCipherTextException if something goes wrong
     */
    public static byte[] handle(boolean forEncryption, byte[] input, byte[] key) throws InvalidCipherTextException {
        CipherParameters cipherParameters = new KeyParameter(key);
        BufferedBlockCipher bufferedBlockCipher = new PaddedBufferedBlockCipher(new AESEngine(),
                new ZeroBytePadding());

        bufferedBlockCipher.init(forEncryption, cipherParameters);

        int inputOffset = 0;
        int inputLength = input.length;

        int maximumOutputLength = bufferedBlockCipher.getOutputSize(inputLength);
        byte[] output = new byte[maximumOutputLength];
        int outputOffset = 0;
        int outputLength = 0;

        int bytesProcessed;

        bytesProcessed = bufferedBlockCipher.processBytes(input, inputOffset, inputLength, output, outputOffset);
        outputOffset += bytesProcessed;
        outputLength += bytesProcessed;

        bytesProcessed = bufferedBlockCipher.doFinal(output, outputOffset);
        outputOffset += bytesProcessed;
        outputLength += bytesProcessed;

        if (outputLength == output.length) {
            return output;
        } else {
            byte[] truncatedOutput = new byte[outputLength];
            System.arraycopy(output, 0, truncatedOutput, 0, outputLength);
            return truncatedOutput;
        }
    }
}