java.security.KeyPairGenerator Maven / Gradle / Ivy
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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 java.security;
import java.security.spec.AlgorithmParameterSpec;
import org.apache.harmony.security.fortress.Engine;
/**
* {@code KeyPairGenerator} is an engine class which is capable of generating a
* private key and its related public key utilizing the algorithm it was
* initialized with.
*
* @see KeyPairGeneratorSpi
*/
public abstract class KeyPairGenerator extends KeyPairGeneratorSpi {
// Store KeyPairGenerator SERVICE name
private static final String SERVICE = "KeyPairGenerator";
// Used to access common engine functionality
private static final Engine ENGINE = new Engine(SERVICE);
// Store SecureRandom
private static final SecureRandom RANDOM = new SecureRandom();
// Store used provider
private Provider provider;
// Store used algorithm
private String algorithm;
/**
* Constructs a new instance of {@code KeyPairGenerator} with the name of
* the algorithm to use.
*
* @param algorithm
* the name of algorithm to use
*/
protected KeyPairGenerator(String algorithm) {
this.algorithm = algorithm;
}
/**
* Returns the name of the algorithm of this {@code KeyPairGenerator}.
*
* @return the name of the algorithm of this {@code KeyPairGenerator}
*/
public String getAlgorithm() {
return algorithm;
}
/**
* Returns a new instance of {@code KeyPairGenerator} that utilizes the
* specified algorithm.
*
* @param algorithm
* the name of the algorithm to use
* @return a new instance of {@code KeyPairGenerator} that utilizes the
* specified algorithm
* @throws NoSuchAlgorithmException if the specified algorithm is not available
* @throws NullPointerException
* if {@code algorithm} is {@code null}
*/
public static KeyPairGenerator getInstance(String algorithm)
throws NoSuchAlgorithmException {
if (algorithm == null) {
throw new NullPointerException("algorithm == null");
}
Engine.SpiAndProvider sap = ENGINE.getInstance(algorithm, null);
Object spi = sap.spi;
Provider provider = sap.provider;
if (spi instanceof KeyPairGenerator) {
KeyPairGenerator result = (KeyPairGenerator) spi;
result.algorithm = algorithm;
result.provider = provider;
return result;
}
return new KeyPairGeneratorImpl((KeyPairGeneratorSpi) spi, provider, algorithm);
}
/**
* Returns a new instance of {@code KeyPairGenerator} that utilizes the
* specified algorithm from the specified provider.
*
* @param algorithm
* the name of the algorithm to use
* @param provider
* the name of the provider
* @return a new instance of {@code KeyPairGenerator} that utilizes the
* specified algorithm from the specified provider
* @throws NoSuchAlgorithmException if the specified algorithm is not available
* @throws NoSuchProviderException if the specified provider is not available
* @throws NullPointerException
* if {@code algorithm} is {@code null}
* @throws IllegalArgumentException if {@code provider == null || provider.isEmpty()}
*/
public static KeyPairGenerator getInstance(String algorithm, String provider)
throws NoSuchAlgorithmException, NoSuchProviderException {
if (provider == null || provider.isEmpty()) {
throw new IllegalArgumentException();
}
Provider impProvider = Security.getProvider(provider);
if (impProvider == null) {
throw new NoSuchProviderException(provider);
}
return getInstance(algorithm, impProvider);
}
/**
* Returns a new instance of {@code KeyPairGenerator} that utilizes the
* specified algorithm from the specified provider.
*
* @param algorithm
* the name of the algorithm to use
* @param provider
* the provider
* @return a new instance of {@code KeyPairGenerator} that utilizes the
* specified algorithm from the specified provider
* @throws NoSuchAlgorithmException if the specified algorithm is not available
* @throws NullPointerException
* if {@code algorithm} is {@code null}
* @throws IllegalArgumentException if {@code provider == null}
*/
public static KeyPairGenerator getInstance(String algorithm,
Provider provider) throws NoSuchAlgorithmException {
if (provider == null) {
throw new IllegalArgumentException("provider == null");
}
if (algorithm == null) {
throw new NullPointerException("algorithm == null");
}
Object spi = ENGINE.getInstance(algorithm, provider, null);
if (spi instanceof KeyPairGenerator) {
KeyPairGenerator result = (KeyPairGenerator) spi;
result.algorithm = algorithm;
result.provider = provider;
return result;
}
return new KeyPairGeneratorImpl((KeyPairGeneratorSpi) spi, provider, algorithm);
}
/**
* Returns the provider associated with this {@code KeyPairGenerator}.
*
* @return the provider associated with this {@code KeyPairGenerator}
*/
public final Provider getProvider() {
return provider;
}
/**
* Initializes this {@code KeyPairGenerator} with the given key size. The
* default parameter set and a default {@code SecureRandom} instance will be
* used.
*
* @param keysize
* the size of the key (number of bits)
*/
public void initialize(int keysize) {
initialize(keysize, RANDOM);
}
/**
* Initializes this {@code KeyPairGenerator} with the given {@code
* AlgorithmParameterSpec}. A default {@code SecureRandom} instance will be
* used.
*
* @param param
* the parameters to use
* @throws InvalidAlgorithmParameterException
* if the specified parameters are not supported
*/
public void initialize(AlgorithmParameterSpec param)
throws InvalidAlgorithmParameterException {
initialize(param, RANDOM);
}
/**
* Computes and returns a new unique {@code KeyPair} each time this method
* is called.
*
* This does exactly the same as {@link #generateKeyPair()}.
*
* @return a new unique {@code KeyPair} each time this method is called
*/
public final KeyPair genKeyPair() {
return generateKeyPair();
}
/**
* Computes and returns a new unique {@code KeyPair} each time this method
* is called.
*
* This does exactly the same as {@link #genKeyPair()}.
*
* @return a new unique {@code KeyPair} each time this method is called
*/
@Override
public KeyPair generateKeyPair() {
return null;
}
/**
* Initializes this {@code KeyPairGenerator} with the given key size and the
* given {@code SecureRandom}. The default parameter set will be used.
*
* @param keysize
* the key size
* @param random
* the source of randomness
*/
@Override
public void initialize(int keysize, SecureRandom random) {
}
/**
* Initializes this {@code KeyPairGenerator} with the given {@code
* AlgorithmParameterSpec} and the given {@code SecureRandom}.
*
* @param param
* the parameters to use
* @param random
* the source of randomness
* @throws InvalidAlgorithmParameterException
* if the specified parameters are not supported
*/
@Override
public void initialize(AlgorithmParameterSpec param, SecureRandom random)
throws InvalidAlgorithmParameterException {
}
/**
*
* Internal class: KeyPairGenerator implementation
*
*/
private static class KeyPairGeneratorImpl extends KeyPairGenerator {
// Save KeyPairGeneratorSpi
private KeyPairGeneratorSpi spiImpl;
private KeyPairGeneratorImpl(KeyPairGeneratorSpi keyPairGeneratorSpi,
Provider provider, String algorithm) {
super(algorithm);
super.provider = provider;
spiImpl = keyPairGeneratorSpi;
}
// implementation of initialize(int keysize, SecureRandom random)
// using corresponding spi initialize() method
@Override
public void initialize(int keysize, SecureRandom random) {
spiImpl.initialize(keysize, random);
}
// implementation of generateKeyPair()
// using corresponding spi generateKeyPair() method
@Override
public KeyPair generateKeyPair() {
return spiImpl.generateKeyPair();
}
// implementation of initialize(int keysize, SecureRandom random)
// using corresponding spi initialize() method
@Override
public void initialize(AlgorithmParameterSpec param, SecureRandom random)
throws InvalidAlgorithmParameterException {
spiImpl.initialize(param, random);
}
}
}