de.codesourcery.eve.apiclient.utils.PasswordCipherProvider.java Source code

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Here is the source code for de.codesourcery.eve.apiclient.utils.PasswordCipherProvider.java

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/**
 * Copyright 2004-2009 Tobias Gierke <tobias.gierke@code-sourcery.de>
 *
 * 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 de.codesourcery.eve.apiclient.utils;

import java.security.spec.InvalidKeySpecException;

import javax.crypto.Cipher;
import javax.crypto.NullCipher;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.PBEKeySpec;
import javax.crypto.spec.PBEParameterSpec;

import org.apache.commons.lang.ArrayUtils;
import org.apache.log4j.Logger;

/**
 * Cipher provider for PBE (password-based encryption).
 *
 * @author tobias.gierke@code-sourcery.de
 */
public final class PasswordCipherProvider implements ICipherProvider {

    private static final Logger log = Logger.getLogger(PasswordCipherProvider.class);

    private final IPasswordProvider passwordProvider;

    public PasswordCipherProvider(IPasswordProvider passwordProvider) {
        this.passwordProvider = passwordProvider;
    }

    /**
     * Returns the password to use for encryption / decryption.
     * 
     * @return password to use or <code>null</code> for no encryption at all.
     */
    protected char[] getPassword() {
        return passwordProvider.getPassword();
    }

    @Override
    public Cipher createCipher(boolean decrypt) {

        final char[] password = getPassword();

        if (ArrayUtils.isEmpty(password)) {
            log.warn("createCipher(): No password , returning NULL cipher.");
            return new NullCipher();
        }

        try {

            final int iterations = 20;

            final byte[] salt = new byte[] { (byte) 0xab, (byte) 0xfe, 0x03, 0x47, (byte) 0xde, (byte) 0x99,
                    (byte) 0xff, 0x1c };

            final PBEParameterSpec pbeSpec = new PBEParameterSpec(salt, iterations);

            final PBEKeySpec spec = new PBEKeySpec(password, salt, iterations);
            final SecretKeyFactory fac = SecretKeyFactory.getInstance("PBEWithMD5andDES");
            final SecretKey secretKey;
            try {
                secretKey = fac.generateSecret(spec);
            } catch (InvalidKeySpecException e) {
                throw e;
            }

            final Cipher cipher = Cipher.getInstance("PBEWithMD5andDES");
            if (decrypt) {
                cipher.init(Cipher.DECRYPT_MODE, secretKey, pbeSpec);
            } else {
                cipher.init(Cipher.ENCRYPT_MODE, secretKey, pbeSpec);
            }
            return cipher;
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }

}