CipherUtils.java

/*
 * Copyright 2010-2011 the original author or authors.
 *
 * 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 com.springsource.greenhouse.database.upgrade.v3;

import java.security.InvalidAlgorithmParameterException;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.security.spec.InvalidKeySpecException;

import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.PBEKeySpec;
import javax.crypto.spec.PBEParameterSpec;

class CipherUtils {

	private CipherUtils() {		
	}

	public static SecretKey newSecretKey(String algorithm, String secret) {
		try {
			PBEKeySpec pbeKeySpec = new PBEKeySpec(secret.toCharArray());
			SecretKeyFactory factory = SecretKeyFactory.getInstance(algorithm);
			return factory.generateSecret(pbeKeySpec);
		} catch (NoSuchAlgorithmException e) {
			throw new IllegalArgumentException("Not a valid encryption algorithm", e);
		} catch (InvalidKeySpecException e) {
			throw new IllegalArgumentException("Not a valid secert key", e);
		}
	}

	public static Cipher newCipher(String algorithm) {
		try {
			return Cipher.getInstance(algorithm);
		} catch (NoSuchAlgorithmException e) {
			throw new IllegalArgumentException("Not a valid encryption algorithm", e);
		} catch (NoSuchPaddingException e) {
			throw new IllegalStateException("Should not happen", e);
		}
	}

	public static void initCipher(Cipher cipher, int mode, SecretKey secretKey, byte[] salt, int iterationCount) {
		try {
			cipher.init(mode, secretKey, new PBEParameterSpec(salt, iterationCount));
		} catch (InvalidKeyException e) {
			throw new IllegalArgumentException("Unable to initialize due to invalid secret key", e);			
		} catch (InvalidAlgorithmParameterException e) {
			throw new IllegalStateException("Unable to initialize due to invalid decryption parameter spec", e);
		}
	}

	public static byte[] doFinal(Cipher cipher, byte[] input) {
		try {
			return cipher.doFinal(input);
		} catch (IllegalBlockSizeException e) {
			throw new IllegalStateException("Unable to invoke Cipher due to illegal block size", e);
		} catch (BadPaddingException e) {
			throw new IllegalStateException("Unable to invoke Cipher due to bad padding", e);
		}		
	}
}