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/*
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* Copyright (c) 1997, 2007, Oracle and/or its affiliates. All rights reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation. Oracle designates this
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* particular file as subject to the "Classpath" exception as provided
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* by Oracle in the LICENSE file that accompanied this code.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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* or visit www.oracle.com if you need additional information or have any
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* questions.
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*/
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package javax.crypto;
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import java.util.*;
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import java.security.*;
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import java.security.Provider.Service;
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import java.security.spec.*;
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import sun.security.util.Debug;
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import sun.security.jca.*;
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import sun.security.jca.GetInstance.Instance;
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/**
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* This class provides the functionality of a key agreement (or key
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* exchange) protocol.
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* <p>
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* The keys involved in establishing a shared secret are created by one of the
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* key generators (<code>KeyPairGenerator</code> or
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* <code>KeyGenerator</code>), a <code>KeyFactory</code>, or as a result from
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* an intermediate phase of the key agreement protocol.
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*
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* <p> For each of the correspondents in the key exchange, <code>doPhase</code>
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* needs to be called. For example, if this key exchange is with one other
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* party, <code>doPhase</code> needs to be called once, with the
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* <code>lastPhase</code> flag set to <code>true</code>.
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* If this key exchange is
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* with two other parties, <code>doPhase</code> needs to be called twice,
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* the first time setting the <code>lastPhase</code> flag to
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* <code>false</code>, and the second time setting it to <code>true</code>.
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* There may be any number of parties involved in a key exchange.
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*
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* @author Jan Luehe
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*
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* @see KeyGenerator
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* @see SecretKey
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* @since 1.4
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*/
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public class KeyAgreement {
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private static final Debug debug =
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Debug.getInstance("jca", "KeyAgreement");
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// The provider
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private Provider provider;
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// The provider implementation (delegate)
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private KeyAgreementSpi spi;
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// The name of the key agreement algorithm.
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private final String algorithm;
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// next service to try in provider selection
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// null once provider is selected
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private Service firstService;
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// remaining services to try in provider selection
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// null once provider is selected
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private Iterator serviceIterator;
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private final Object lock;
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/**
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* Creates a KeyAgreement object.
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*
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* @param keyAgreeSpi the delegate
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* @param provider the provider
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* @param algorithm the algorithm
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*/
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protected KeyAgreement(KeyAgreementSpi keyAgreeSpi, Provider provider,
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String algorithm) {
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this.spi = keyAgreeSpi;
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this.provider = provider;
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this.algorithm = algorithm;
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lock = null;
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}
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private KeyAgreement(Service s, Iterator t, String algorithm) {
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firstService = s;
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serviceIterator = t;
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this.algorithm = algorithm;
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lock = new Object();
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}
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/**
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* Returns the algorithm name of this <code>KeyAgreement</code> object.
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*
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* <p>This is the same name that was specified in one of the
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* <code>getInstance</code> calls that created this
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* <code>KeyAgreement</code> object.
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*
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* @return the algorithm name of this <code>KeyAgreement</code> object.
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*/
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public final String getAlgorithm() {
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return this.algorithm;
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}
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/**
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* Returns a <code>KeyAgreement</code> object that implements the
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* specified key agreement algorithm.
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*
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* <p> This method traverses the list of registered security Providers,
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* starting with the most preferred Provider.
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* A new KeyAgreement object encapsulating the
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* KeyAgreementSpi implementation from the first
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* Provider that supports the specified algorithm is returned.
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*
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* <p> Note that the list of registered providers may be retrieved via
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* the {@link Security#getProviders() Security.getProviders()} method.
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*
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* @param algorithm the standard name of the requested key agreement
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* algorithm.
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* See Appendix A in the
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* <a href=
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* "{@docRoot}/../technotes/guides/security/crypto/CryptoSpec.html#AppA">
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* Java Cryptography Architecture Reference Guide</a>
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* for information about standard algorithm names.
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*
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* @return the new <code>KeyAgreement</code> object.
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*
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* @exception NullPointerException if the specified algorithm
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* is null.
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*
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* @exception NoSuchAlgorithmException if no Provider supports a
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* KeyAgreementSpi implementation for the
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* specified algorithm.
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*
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* @see java.security.Provider
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*/
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public static final KeyAgreement getInstance(String algorithm)
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throws NoSuchAlgorithmException {
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List services = GetInstance.getServices("KeyAgreement", algorithm);
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// make sure there is at least one service from a signed provider
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Iterator t = services.iterator();
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while (t.hasNext()) {
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Service s = (Service)t.next();
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if (JceSecurity.canUseProvider(s.getProvider()) == false) {
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continue;
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}
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return new KeyAgreement(s, t, algorithm);
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}
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throw new NoSuchAlgorithmException
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("Algorithm " + algorithm + " not available");
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}
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/**
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* Returns a <code>KeyAgreement</code> object that implements the
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* specified key agreement algorithm.
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*
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* <p> A new KeyAgreement object encapsulating the
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* KeyAgreementSpi implementation from the specified provider
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* is returned. The specified provider must be registered
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* in the security provider list.
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*
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* <p> Note that the list of registered providers may be retrieved via
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* the {@link Security#getProviders() Security.getProviders()} method.
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*
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* @param algorithm the standard name of the requested key agreement
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* algorithm.
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* See Appendix A in the
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* <a href=
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* "{@docRoot}/../technotes/guides/security/crypto/CryptoSpec.html#AppA">
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* Java Cryptography Architecture Reference Guide</a>
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* for information about standard algorithm names.
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*
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* @param provider the name of the provider.
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*
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* @return the new <code>KeyAgreement</code> object.
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*
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* @exception NullPointerException if the specified algorithm
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* is null.
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*
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* @exception NoSuchAlgorithmException if a KeyAgreementSpi
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* implementation for the specified algorithm is not
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* available from the specified provider.
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*
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* @exception NoSuchProviderException if the specified provider is not
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* registered in the security provider list.
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*
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* @exception IllegalArgumentException if the <code>provider</code>
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* is null or empty.
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*
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* @see java.security.Provider
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*/
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public static final KeyAgreement getInstance(String algorithm,
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String provider) throws NoSuchAlgorithmException,
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NoSuchProviderException {
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Instance instance = JceSecurity.getInstance
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("KeyAgreement", KeyAgreementSpi.class, algorithm, provider);
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return new KeyAgreement((KeyAgreementSpi)instance.impl,
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instance.provider, algorithm);
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}
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/**
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* Returns a <code>KeyAgreement</code> object that implements the
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* specified key agreement algorithm.
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*
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* <p> A new KeyAgreement object encapsulating the
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* KeyAgreementSpi implementation from the specified Provider
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* object is returned. Note that the specified Provider object
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* does not have to be registered in the provider list.
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*
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* @param algorithm the standard name of the requested key agreement
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* algorithm.
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* See Appendix A in the
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* <a href=
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* "{@docRoot}/../technotes/guides/security/crypto/CryptoSpec.html#AppA">
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* Java Cryptography Architecture Reference Guide</a>
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* for information about standard algorithm names.
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*
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* @param provider the provider.
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*
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* @return the new <code>KeyAgreement</code> object.
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*
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* @exception NullPointerException if the specified algorithm
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* is null.
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*
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* @exception NoSuchAlgorithmException if a KeyAgreementSpi
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* implementation for the specified algorithm is not available
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* from the specified Provider object.
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*
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* @exception IllegalArgumentException if the <code>provider</code>
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* is null.
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*
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* @see java.security.Provider
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*/
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public static final KeyAgreement getInstance(String algorithm,
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Provider provider) throws NoSuchAlgorithmException {
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Instance instance = JceSecurity.getInstance
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("KeyAgreement", KeyAgreementSpi.class, algorithm, provider);
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return new KeyAgreement((KeyAgreementSpi)instance.impl,
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instance.provider, algorithm);
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}
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// max number of debug warnings to print from chooseFirstProvider()
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private static int warnCount = 10;
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/**
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* Choose the Spi from the first provider available. Used if
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* delayed provider selection is not possible because init()
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* is not the first method called.
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*/
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void chooseFirstProvider() {
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if (spi != null) {
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return;
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}
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synchronized (lock) {
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if (spi != null) {
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return;
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}
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if (debug != null) {
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int w = --warnCount;
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if (w >= 0) {
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debug.println("KeyAgreement.init() not first method "
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+ "called, disabling delayed provider selection");
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if (w == 0) {
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debug.println("Further warnings of this type will "
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+ "be suppressed");
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}
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new Exception("Call trace").printStackTrace();
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}
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}
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Exception lastException = null;
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while ((firstService != null) || serviceIterator.hasNext()) {
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Service s;
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if (firstService != null) {
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s = firstService;
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firstService = null;
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} else {
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s = (Service)serviceIterator.next();
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}
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if (JceSecurity.canUseProvider(s.getProvider()) == false) {
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continue;
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}
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try {
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Object obj = s.newInstance(null);
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if (obj instanceof KeyAgreementSpi == false) {
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continue;
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}
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spi = (KeyAgreementSpi)obj;
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provider = s.getProvider();
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// not needed any more
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firstService = null;
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serviceIterator = null;
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return;
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} catch (Exception e) {
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lastException = e;
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}
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}
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ProviderException e = new ProviderException
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("Could not construct KeyAgreementSpi instance");
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if (lastException != null) {
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e.initCause(lastException);
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}
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throw e;
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}
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}
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private final static int I_NO_PARAMS = 1;
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private final static int I_PARAMS = 2;
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private void implInit(KeyAgreementSpi spi, int type, Key key,
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AlgorithmParameterSpec params, SecureRandom random)
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throws InvalidKeyException, InvalidAlgorithmParameterException {
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if (type == I_NO_PARAMS) {
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spi.engineInit(key, random);
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} else { // I_PARAMS
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spi.engineInit(key, params, random);
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}
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}
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private void chooseProvider(int initType, Key key,
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AlgorithmParameterSpec params, SecureRandom random)
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throws InvalidKeyException, InvalidAlgorithmParameterException {
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synchronized (lock) {
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if (spi != null) {
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implInit(spi, initType, key, params, random);
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return;
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}
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Exception lastException = null;
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while ((firstService != null) || serviceIterator.hasNext()) {
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Service s;
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if (firstService != null) {
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s = firstService;
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firstService = null;
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} else {
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s = (Service)serviceIterator.next();
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}
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// if provider says it does not support this key, ignore it
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if (s.supportsParameter(key) == false) {
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continue;
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}
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if (JceSecurity.canUseProvider(s.getProvider()) == false) {
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continue;
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}
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try {
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KeyAgreementSpi spi = (KeyAgreementSpi)s.newInstance(null);
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implInit(spi, initType, key, params, random);
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provider = s.getProvider();
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this.spi = spi;
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firstService = null;
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serviceIterator = null;
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return;
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} catch (Exception e) {
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// NoSuchAlgorithmException from newInstance()
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// InvalidKeyException from init()
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// RuntimeException (ProviderException) from init()
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if (lastException == null) {
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lastException = e;
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}
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}
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}
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// no working provider found, fail
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if (lastException instanceof InvalidKeyException) {
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throw (InvalidKeyException)lastException;
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}
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if (lastException instanceof InvalidAlgorithmParameterException) {
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throw (InvalidAlgorithmParameterException)lastException;
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}
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if (lastException instanceof RuntimeException) {
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throw (RuntimeException)lastException;
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}
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String kName = (key != null) ? key.getClass().getName() : "(null)";
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throw new InvalidKeyException
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("No installed provider supports this key: "
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+ kName, lastException);
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}
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}
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394 |
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/**
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* Returns the provider of this <code>KeyAgreement</code> object.
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*
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|
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* @return the provider of this <code>KeyAgreement</code> object
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*/
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400 |
public final Provider getProvider() {
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chooseFirstProvider();
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return this.provider;
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}
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405 |
/**
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|
406 |
* Initializes this key agreement with the given key, which is required to
|
|
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* contain all the algorithm parameters required for this key agreement.
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|
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*
|
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* <p> If this key agreement requires any random bytes, it will get
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* them using the
|
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411 |
* {@link SecureRandom <code>SecureRandom</code>}
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|
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* implementation of the highest-priority
|
|
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* installed provider as the source of randomness.
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|
414 |
* (If none of the installed providers supply an implementation of
|
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* SecureRandom, a system-provided source of randomness will be used.)
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|
416 |
*
|
|
417 |
* @param key the party's private information. For example, in the case
|
|
418 |
* of the Diffie-Hellman key agreement, this would be the party's own
|
|
419 |
* Diffie-Hellman private key.
|
|
420 |
*
|
|
421 |
* @exception InvalidKeyException if the given key is
|
|
422 |
* inappropriate for this key agreement, e.g., is of the wrong type or
|
|
423 |
* has an incompatible algorithm type.
|
|
424 |
*/
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|
425 |
public final void init(Key key) throws InvalidKeyException {
|
|
426 |
init(key, JceSecurity.RANDOM);
|
|
427 |
}
|
|
428 |
|
|
429 |
/**
|
|
430 |
* Initializes this key agreement with the given key and source of
|
|
431 |
* randomness. The given key is required to contain all the algorithm
|
|
432 |
* parameters required for this key agreement.
|
|
433 |
*
|
|
434 |
* <p> If the key agreement algorithm requires random bytes, it gets them
|
|
435 |
* from the given source of randomness, <code>random</code>.
|
|
436 |
* However, if the underlying
|
|
437 |
* algorithm implementation does not require any random bytes,
|
|
438 |
* <code>random</code> is ignored.
|
|
439 |
*
|
|
440 |
* @param key the party's private information. For example, in the case
|
|
441 |
* of the Diffie-Hellman key agreement, this would be the party's own
|
|
442 |
* Diffie-Hellman private key.
|
|
443 |
* @param random the source of randomness
|
|
444 |
*
|
|
445 |
* @exception InvalidKeyException if the given key is
|
|
446 |
* inappropriate for this key agreement, e.g., is of the wrong type or
|
|
447 |
* has an incompatible algorithm type.
|
|
448 |
*/
|
|
449 |
public final void init(Key key, SecureRandom random)
|
|
450 |
throws InvalidKeyException {
|
|
451 |
if (spi != null) {
|
|
452 |
spi.engineInit(key, random);
|
|
453 |
} else {
|
|
454 |
try {
|
|
455 |
chooseProvider(I_NO_PARAMS, key, null, random);
|
|
456 |
} catch (InvalidAlgorithmParameterException e) {
|
|
457 |
// should never occur
|
|
458 |
throw new InvalidKeyException(e);
|
|
459 |
}
|
|
460 |
}
|
|
461 |
}
|
|
462 |
|
|
463 |
/**
|
|
464 |
* Initializes this key agreement with the given key and set of
|
|
465 |
* algorithm parameters.
|
|
466 |
*
|
|
467 |
* <p> If this key agreement requires any random bytes, it will get
|
|
468 |
* them using the
|
|
469 |
* {@link SecureRandom <code>SecureRandom</code>}
|
|
470 |
* implementation of the highest-priority
|
|
471 |
* installed provider as the source of randomness.
|
|
472 |
* (If none of the installed providers supply an implementation of
|
|
473 |
* SecureRandom, a system-provided source of randomness will be used.)
|
|
474 |
*
|
|
475 |
* @param key the party's private information. For example, in the case
|
|
476 |
* of the Diffie-Hellman key agreement, this would be the party's own
|
|
477 |
* Diffie-Hellman private key.
|
|
478 |
* @param params the key agreement parameters
|
|
479 |
*
|
|
480 |
* @exception InvalidKeyException if the given key is
|
|
481 |
* inappropriate for this key agreement, e.g., is of the wrong type or
|
|
482 |
* has an incompatible algorithm type.
|
|
483 |
* @exception InvalidAlgorithmParameterException if the given parameters
|
|
484 |
* are inappropriate for this key agreement.
|
|
485 |
*/
|
|
486 |
public final void init(Key key, AlgorithmParameterSpec params)
|
|
487 |
throws InvalidKeyException, InvalidAlgorithmParameterException
|
|
488 |
{
|
|
489 |
init(key, params, JceSecurity.RANDOM);
|
|
490 |
}
|
|
491 |
|
|
492 |
/**
|
|
493 |
* Initializes this key agreement with the given key, set of
|
|
494 |
* algorithm parameters, and source of randomness.
|
|
495 |
*
|
|
496 |
* @param key the party's private information. For example, in the case
|
|
497 |
* of the Diffie-Hellman key agreement, this would be the party's own
|
|
498 |
* Diffie-Hellman private key.
|
|
499 |
* @param params the key agreement parameters
|
|
500 |
* @param random the source of randomness
|
|
501 |
*
|
|
502 |
* @exception InvalidKeyException if the given key is
|
|
503 |
* inappropriate for this key agreement, e.g., is of the wrong type or
|
|
504 |
* has an incompatible algorithm type.
|
|
505 |
* @exception InvalidAlgorithmParameterException if the given parameters
|
|
506 |
* are inappropriate for this key agreement.
|
|
507 |
*/
|
|
508 |
public final void init(Key key, AlgorithmParameterSpec params,
|
|
509 |
SecureRandom random)
|
|
510 |
throws InvalidKeyException, InvalidAlgorithmParameterException
|
|
511 |
{
|
|
512 |
if (spi != null) {
|
|
513 |
spi.engineInit(key, params, random);
|
|
514 |
} else {
|
|
515 |
chooseProvider(I_PARAMS, key, params, random);
|
|
516 |
}
|
|
517 |
}
|
|
518 |
|
|
519 |
/**
|
|
520 |
* Executes the next phase of this key agreement with the given
|
|
521 |
* key that was received from one of the other parties involved in this key
|
|
522 |
* agreement.
|
|
523 |
*
|
|
524 |
* @param key the key for this phase. For example, in the case of
|
|
525 |
* Diffie-Hellman between 2 parties, this would be the other party's
|
|
526 |
* Diffie-Hellman public key.
|
|
527 |
* @param lastPhase flag which indicates whether or not this is the last
|
|
528 |
* phase of this key agreement.
|
|
529 |
*
|
|
530 |
* @return the (intermediate) key resulting from this phase, or null
|
|
531 |
* if this phase does not yield a key
|
|
532 |
*
|
|
533 |
* @exception InvalidKeyException if the given key is inappropriate for
|
|
534 |
* this phase.
|
|
535 |
* @exception IllegalStateException if this key agreement has not been
|
|
536 |
* initialized.
|
|
537 |
*/
|
|
538 |
public final Key doPhase(Key key, boolean lastPhase)
|
|
539 |
throws InvalidKeyException, IllegalStateException
|
|
540 |
{
|
|
541 |
chooseFirstProvider();
|
|
542 |
return spi.engineDoPhase(key, lastPhase);
|
|
543 |
}
|
|
544 |
|
|
545 |
/**
|
|
546 |
* Generates the shared secret and returns it in a new buffer.
|
|
547 |
*
|
|
548 |
* <p>This method resets this <code>KeyAgreement</code> object, so that it
|
|
549 |
* can be reused for further key agreements. Unless this key agreement is
|
|
550 |
* reinitialized with one of the <code>init</code> methods, the same
|
|
551 |
* private information and algorithm parameters will be used for
|
|
552 |
* subsequent key agreements.
|
|
553 |
*
|
|
554 |
* @return the new buffer with the shared secret
|
|
555 |
*
|
|
556 |
* @exception IllegalStateException if this key agreement has not been
|
|
557 |
* completed yet
|
|
558 |
*/
|
|
559 |
public final byte[] generateSecret() throws IllegalStateException {
|
|
560 |
chooseFirstProvider();
|
|
561 |
return spi.engineGenerateSecret();
|
|
562 |
}
|
|
563 |
|
|
564 |
/**
|
|
565 |
* Generates the shared secret, and places it into the buffer
|
|
566 |
* <code>sharedSecret</code>, beginning at <code>offset</code> inclusive.
|
|
567 |
*
|
|
568 |
* <p>If the <code>sharedSecret</code> buffer is too small to hold the
|
|
569 |
* result, a <code>ShortBufferException</code> is thrown.
|
|
570 |
* In this case, this call should be repeated with a larger output buffer.
|
|
571 |
*
|
|
572 |
* <p>This method resets this <code>KeyAgreement</code> object, so that it
|
|
573 |
* can be reused for further key agreements. Unless this key agreement is
|
|
574 |
* reinitialized with one of the <code>init</code> methods, the same
|
|
575 |
* private information and algorithm parameters will be used for
|
|
576 |
* subsequent key agreements.
|
|
577 |
*
|
|
578 |
* @param sharedSecret the buffer for the shared secret
|
|
579 |
* @param offset the offset in <code>sharedSecret</code> where the
|
|
580 |
* shared secret will be stored
|
|
581 |
*
|
|
582 |
* @return the number of bytes placed into <code>sharedSecret</code>
|
|
583 |
*
|
|
584 |
* @exception IllegalStateException if this key agreement has not been
|
|
585 |
* completed yet
|
|
586 |
* @exception ShortBufferException if the given output buffer is too small
|
|
587 |
* to hold the secret
|
|
588 |
*/
|
|
589 |
public final int generateSecret(byte[] sharedSecret, int offset)
|
|
590 |
throws IllegalStateException, ShortBufferException
|
|
591 |
{
|
|
592 |
chooseFirstProvider();
|
|
593 |
return spi.engineGenerateSecret(sharedSecret, offset);
|
|
594 |
}
|
|
595 |
|
|
596 |
/**
|
|
597 |
* Creates the shared secret and returns it as a <code>SecretKey</code>
|
|
598 |
* object of the specified algorithm.
|
|
599 |
*
|
|
600 |
* <p>This method resets this <code>KeyAgreement</code> object, so that it
|
|
601 |
* can be reused for further key agreements. Unless this key agreement is
|
|
602 |
* reinitialized with one of the <code>init</code> methods, the same
|
|
603 |
* private information and algorithm parameters will be used for
|
|
604 |
* subsequent key agreements.
|
|
605 |
*
|
|
606 |
* @param algorithm the requested secret-key algorithm
|
|
607 |
*
|
|
608 |
* @return the shared secret key
|
|
609 |
*
|
|
610 |
* @exception IllegalStateException if this key agreement has not been
|
|
611 |
* completed yet
|
|
612 |
* @exception NoSuchAlgorithmException if the specified secret-key
|
|
613 |
* algorithm is not available
|
|
614 |
* @exception InvalidKeyException if the shared secret-key material cannot
|
|
615 |
* be used to generate a secret key of the specified algorithm (e.g.,
|
|
616 |
* the key material is too short)
|
|
617 |
*/
|
|
618 |
public final SecretKey generateSecret(String algorithm)
|
|
619 |
throws IllegalStateException, NoSuchAlgorithmException,
|
|
620 |
InvalidKeyException
|
|
621 |
{
|
|
622 |
chooseFirstProvider();
|
|
623 |
return spi.engineGenerateSecret(algorithm);
|
|
624 |
}
|
|
625 |
}
|