net.sourceforge.jaulp.crypto.SimpleDecryptor Maven / Gradle / Ivy
/**
* Copyright (C) 2007 Asterios Raptis
*
* 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 net.sourceforge.jaulp.crypto;
import java.io.UnsupportedEncodingException;
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.KeySpec;
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;
import lombok.AccessLevel;
import lombok.Getter;
import net.sourceforge.jaulp.check.Check;
import net.sourceforge.jaulp.crypto.interfaces.Decryptor;
import org.apache.commons.codec.binary.Base64;
/**
* A simple Decryptor implementation.
*
* @author Asterios Raptis
* @version 1.0
*/
public class SimpleDecryptor implements Decryptor
{
/**
* The Cipher object.
*/
private Cipher cipher;
/**
* The private key.
*/
@Getter
private final String privateKey;
/**
* The flag initialized that indicates if the cypher is initialized for decryption.
*
* @return true, if is initialized
*/
@Getter(value = AccessLevel.PRIVATE)
private boolean initialized;
/**
* Constructor with a private key.
*
* @param privateKey
* The private key.
*/
public SimpleDecryptor(final String privateKey)
{
Check.get().notEmpty(privateKey, "privateKey");
this.privateKey = privateKey;
}
/**
* Decrpyt the given encrypted String.
*
* @param encypted
* The String to decrypt.
* @throws BadPaddingException
* is thrown if {@link Cipher#doFinal(byte[])} fails.
* @throws IllegalBlockSizeException
* is thrown if {@link Cipher#doFinal(byte[])} fails.
* @throws UnsupportedEncodingException
* is thrown if creation of String object fails.
* @throws InvalidAlgorithmParameterException
* is thrown if initialization of the cypher object fails.
* @throws NoSuchPaddingException
* is thrown if instantiation of the cypher object fails.
* @throws InvalidKeySpecException
* is thrown if generation of the SecretKey object fails.
* @throws NoSuchAlgorithmException
* is thrown if instantiation of the SecretKeyFactory object fails.
* @throws InvalidKeyException
* is thrown if initialization of the cypher object fails.
*
* @see net.sourceforge.jaulp.crypto.interfaces.Decryptor#decrypt(java.lang.String)
*/
@Override
public String decrypt(final String encypted) throws IllegalBlockSizeException,
BadPaddingException, UnsupportedEncodingException, InvalidKeyException,
NoSuchAlgorithmException, InvalidKeySpecException, NoSuchPaddingException,
InvalidAlgorithmParameterException
{
initialize();
final byte[] dec = Base64.decodeBase64(encypted);
final byte[] utf8 = this.cipher.doFinal(dec);
return new String(utf8, CryptConst.ENCODING);
}
/**
* Initializes the {@link SimpleDecryptor} object.
*
* @throws InvalidAlgorithmParameterException
* is thrown if initialization of the cypher object fails.
* @throws NoSuchPaddingException
* is thrown if instantiation of the cypher object fails.
* @throws InvalidKeySpecException
* is thrown if generation of the SecretKey object fails.
* @throws NoSuchAlgorithmException
* is thrown if instantiation of the SecretKeyFactory object fails.
* @throws InvalidKeyException
* is thrown if initialization of the cypher object fails.
*/
private void initialize() throws NoSuchAlgorithmException, InvalidKeySpecException,
NoSuchPaddingException, InvalidKeyException, InvalidAlgorithmParameterException
{
if (!isInitialized())
{
KeySpec keySpec = null;
if (this.getPrivateKey() != null)
{
keySpec = new PBEKeySpec(this.getPrivateKey().toCharArray());
}
if (this.getPrivateKey() == null)
{
keySpec = new PBEKeySpec(CryptConst.PRIVATE_KEY.toCharArray());
}
final SecretKeyFactory factory = SecretKeyFactory
.getInstance(CryptConst.PBEWITH_MD5AND_DES);
final SecretKey key = factory.generateSecret(keySpec);
this.cipher = Cipher.getInstance(key.getAlgorithm());
final AlgorithmParameterSpec paramSpec = new PBEParameterSpec(CryptConst.SALT,
CryptConst.ITERATIONCOUNT);
this.cipher.init(Cipher.DECRYPT_MODE, key, paramSpec);
initialized = true;
}
}
}
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