/*
* Copyright 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 org.springframework.security.crypto.encrypt;
import java.security.InvalidAlgorithmParameterException;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.security.spec.AlgorithmParameterSpec;
import java.security.spec.InvalidKeySpecException;
import java.security.spec.InvalidParameterSpecException;
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;
/**
* Static helper for working with the Cipher API.
* @author Keith Donald
*/
class CipherUtils {
/**
* Generates a SecretKey.
*/
public static SecretKey newSecretKey(String algorithm, String password) {
return newSecretKey(algorithm, new PBEKeySpec(password.toCharArray()));
}
/**
* Generates a SecretKey.
*/
public static SecretKey newSecretKey(String algorithm, PBEKeySpec keySpec) {
try {
SecretKeyFactory factory = SecretKeyFactory.getInstance(algorithm);
return factory.generateSecret(keySpec);
} catch (NoSuchAlgorithmException e) {
throw new IllegalArgumentException("Not a valid encryption algorithm", e);
} catch (InvalidKeySpecException e) {
throw new IllegalArgumentException("Not a valid secret key", e);
}
}
/**
* Constructs a new Cipher.
*/
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);
}
}
/**
* Initializes the Cipher for use.
*/
public static <T extends AlgorithmParameterSpec> T getParameterSpec(Cipher cipher, Class<T> parameterSpecClass) {
try {
return cipher.getParameters().getParameterSpec(parameterSpecClass);
} catch (InvalidParameterSpecException e) {
throw new IllegalArgumentException("Unable to access parameter", e);
}
}
/**
* Initializes the Cipher for use.
*/
public static void initCipher(Cipher cipher, int mode, SecretKey secretKey) {
initCipher(cipher, mode, secretKey, null);
}
/**
* Initializes the Cipher for use.
*/
public static void initCipher(Cipher cipher, int mode, SecretKey secretKey, byte[] salt, int iterationCount) {
initCipher(cipher, mode, secretKey, new PBEParameterSpec(salt, iterationCount));
}
/**
* Initializes the Cipher for use.
*/
public static void initCipher(Cipher cipher, int mode, SecretKey secretKey, AlgorithmParameterSpec parameterSpec) {
try {
if (parameterSpec != null) {
cipher.init(mode, secretKey, parameterSpec);
} else {
cipher.init(mode, secretKey);
}
} 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);
}
}
/**
* Invokes the Cipher to perform encryption or decryption (depending on the initialized mode).
*/
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);
}
}
private CipherUtils() {
}
}