/**
* Copyright 2005-2013 hdiv.org
*
* 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.hdiv.cipher;
import java.security.NoSuchAlgorithmException;
import java.security.NoSuchProviderException;
import java.security.SecureRandom;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;
import org.hdiv.exception.HDIVException;
import org.hdiv.util.HDIVUtil;
/**
* Key Factory generator.
*
* @author Roberto Velasco
*/
public class KeyFactory implements IKeyFactory {
/**
* Name of the default PRNG algorithm
*/
public static final String DEFAULT_PRNG_ALGORITHM = "SHA1PRNG";
/**
* Name of the default PRNG algorithm
*/
public static final String DEFAULT_ALGORITHM = "AES";
/**
* Pseudo Random Number Generator algorithm
*
* @see See Appendix A in the Java Cryptography Architecture API Specification & Reference for information about
* standard PRNG algorithm names.
*/
private String prngAlgorithm = DEFAULT_PRNG_ALGORITHM;
/**
* Algorithm for the Key Generator
*/
private String algorithm = DEFAULT_ALGORITHM;
/**
* This is an algorithm-specific metric, specified in number of bits.
*/
private int keySize;
/**
* Provider name
*/
private String provider;
/**
* This method is called whenever a key needs to be generated.
*
* @return Key the encryption key
*/
public Key generateKey() {
try {
// Create a secure random number generator
SecureRandom random;
if (this.provider == null) {
// Use default provider
random = SecureRandom.getInstance(this.prngAlgorithm);
} else {
random = SecureRandom.getInstance(this.prngAlgorithm, this.provider);
}
byte[] iv = new byte[16];
random.nextBytes(iv);
// Get the key Generator
KeyGenerator kgen = KeyGenerator.getInstance(this.algorithm);
if (this.keySize == 0) {
// Use default keysize
kgen.init(random);
} else {
kgen.init(this.keySize, random);
}
// Generate the key specs
SecretKey skey = kgen.generateKey();
byte[] raw = skey.getEncoded();
SecretKeySpec skeySpec = new SecretKeySpec(raw, this.algorithm);
Key key = new Key();
key.setKey(skeySpec);
key.setInitVector(iv);
return key;
} catch (NoSuchAlgorithmException e) {
String errorMessage = HDIVUtil.getMessage("key.factory.generate", e.getMessage());
throw new HDIVException(errorMessage, e);
} catch (NoSuchProviderException e) {
String errorMessage = HDIVUtil.getMessage("key.factory.generate", e.getMessage());
throw new HDIVException(errorMessage, e);
}
}
/**
* @return Returns the algorithm for the Key Generator.
*/
public String getAlgorithm() {
return algorithm;
}
/**
* @param algorithm
* The algorithm to set for the Key Generator.
*/
public void setAlgorithm(String algorithm) {
this.algorithm = algorithm;
}
/**
*
* @return Returns the key size
*/
public int getKeySize() {
return keySize;
}
/**
* @param keySize
* The keySize to set
*/
public void setKeySize(int keySize) {
this.keySize = keySize;
}
/**
* @return Returns the provider name.
*/
public String getProvider() {
return provider;
}
/**
* @param provider
* The provider to set.
*/
public void setProvider(String provider) {
this.provider = provider;
}
/**
* @return Returns the prngAlgorithm.
*/
public String getPrngAlgorithm() {
return prngAlgorithm;
}
/**
* @param prngAlgorithm
* The prngAlgorithm to set.
*/
public void setPrngAlgorithm(String prngAlgorithm) {
this.prngAlgorithm = prngAlgorithm;
}
}