org.toffi.domainmodel.encryptor.impl.AESEncryptorImpl.java Source code

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Here is the source code for org.toffi.domainmodel.encryptor.impl.AESEncryptorImpl.java

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/*
 * org.toffi
 *
 * File Name: AESEncryptorImpl.java
 *
 * Copyright 2014 Dzhem Riza
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.toffi.domainmodel.encryptor.impl;

import org.apache.commons.codec.digest.DigestUtils;
import org.apache.log4j.Logger;
import org.toffi.domainmodel.encryptor.Encryptor;
import org.toffi.domainmodel.encryptor.exceptions.EncryptorException;

import javax.crypto.Cipher;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;
import java.security.SecureRandom;

/**
 * Password based encryption using AES.
 */
public class AESEncryptorImpl implements Encryptor {

    private final Logger LOG = Logger.getLogger(AESEncryptorImpl.class);

    private final SecretKeySpec key;
    private final SecureRandom random;
    private final Cipher encCipher;
    private final Cipher decCipher;
    private final int ivLen;

    /**
     * Initializes encryptor with current encryption key.
     *
     * @param password
     */
    public AESEncryptorImpl(String password) {
        try {
            // key = new SecretKeySpec(DigestUtils.sha256(password), "AES");
            key = new SecretKeySpec(DigestUtils.sha256(password), 0, 16, Constants.AES);

            // initialize secure random
            random = SecureRandom.getInstance(Constants.SHA1PRNG);

            // initialize ciphers
            encCipher = Cipher.getInstance(Constants.AES_MODE);
            decCipher = Cipher.getInstance(Constants.AES_MODE);
            ivLen = encCipher.getBlockSize();
        } catch (Exception e) {
            throw new EncryptorException("Error while initializing AESEncryptorImpl.", e);
        }
    }

    @Override
    public byte[] encrypt(byte[] data) {
        try {
            // generate random initialization vector
            byte[] iv = new byte[ivLen];
            synchronized (random) {
                random.nextBytes(iv);
            }

            // encrypt
            IvParameterSpec paramSpec = new IvParameterSpec(iv);
            byte[] encryptedMessage = null;
            synchronized (encCipher) {
                encCipher.init(Cipher.ENCRYPT_MODE, key, paramSpec);
                encryptedMessage = encCipher.doFinal(data);
            }
            // finalMessage = iv + encryptedMessage
            byte[] finalMessage = new byte[encryptedMessage.length + ivLen];
            System.arraycopy(iv, 0, finalMessage, 0, ivLen);
            System.arraycopy(encryptedMessage, 0, finalMessage, ivLen, encryptedMessage.length);

            return finalMessage;
        } catch (Exception e) {
            LOG.error("Unable to decrypt input message", e);
            throw new EncryptorException("Encryption error!", e);
        }
    }

    @Override
    public byte[] decrypt(byte[] data) {
        try {
            // split message in iv - cipheredMessage
            int cipheredMessageLen = data.length - ivLen;
            byte[] iv = new byte[ivLen];
            byte[] cipheredMessage = new byte[cipheredMessageLen];
            System.arraycopy(data, 0, iv, 0, ivLen);
            System.arraycopy(data, ivLen, cipheredMessage, 0, cipheredMessageLen);

            // decrypt
            byte[] decryptedMessage = null;
            IvParameterSpec paramSpec = new IvParameterSpec(iv);
            synchronized (decCipher) {
                decCipher.init(Cipher.DECRYPT_MODE, key, paramSpec);
                decryptedMessage = decCipher.doFinal(cipheredMessage);
            }

            return decryptedMessage;
        } catch (Exception e) {
            LOG.error("Unable to decrypt input message", e);
            throw new EncryptorException("Decryption error!", e);
        }
    }
}