205 lines
8.6 KiB
Java
205 lines
8.6 KiB
Java
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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.security.*;
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import java.security.spec.*;
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/**
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* This class defines the <i>Service Provider Interface</i> (<b>SPI</b>)
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* for the <code>KeyAgreement</code> class.
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* All the abstract methods in this class must be implemented by each
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* cryptographic service provider who wishes to supply the implementation
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* of a particular key agreement algorithm.
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*
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* <p> The keys involved in establishing a shared secret are created by one
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* 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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* ({@link #engineDoPhase(java.security.Key, boolean) engineDoPhase}).
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*
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* <p> For each of the correspondents in the key exchange,
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* <code>engineDoPhase</code>
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* needs to be called. For example, if the key exchange is with one other
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* party, <code>engineDoPhase</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 the key exchange is
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* with two other parties, <code>engineDoPhase</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 abstract class KeyAgreementSpi {
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/**
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* Initializes this key agreement with the given key and source of
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* randomness. The given key is required to contain all the algorithm
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* parameters required for this key agreement.
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*
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* <p> If the key agreement algorithm requires random bytes, it gets them
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* from the given source of randomness, <code>random</code>.
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* However, if the underlying
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* algorithm implementation does not require any random bytes,
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* <code>random</code> is ignored.
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*
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* @param key the party's private information. For example, in the case
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* of the Diffie-Hellman key agreement, this would be the party's own
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* Diffie-Hellman private key.
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* @param random the source of randomness
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*
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* @exception InvalidKeyException if the given key is
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* inappropriate for this key agreement, e.g., is of the wrong type or
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* has an incompatible algorithm type.
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*/
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protected abstract void engineInit(Key key, SecureRandom random)
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throws InvalidKeyException;
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/**
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* Initializes this key agreement with the given key, set of
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* algorithm parameters, and source of randomness.
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*
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* @param key the party's private information. For example, in the case
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* of the Diffie-Hellman key agreement, this would be the party's own
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* Diffie-Hellman private key.
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* @param params the key agreement parameters
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* @param random the source of randomness
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*
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* @exception InvalidKeyException if the given key is
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* inappropriate for this key agreement, e.g., is of the wrong type or
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* has an incompatible algorithm type.
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* @exception InvalidAlgorithmParameterException if the given parameters
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* are inappropriate for this key agreement.
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*/
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protected abstract void engineInit(Key key, AlgorithmParameterSpec params,
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SecureRandom random)
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throws InvalidKeyException, InvalidAlgorithmParameterException;
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/**
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* Executes the next phase of this key agreement with the given
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* key that was received from one of the other parties involved in this key
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* agreement.
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*
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* @param key the key for this phase. For example, in the case of
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* Diffie-Hellman between 2 parties, this would be the other party's
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* Diffie-Hellman public key.
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* @param lastPhase flag which indicates whether or not this is the last
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* phase of this key agreement.
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*
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* @return the (intermediate) key resulting from this phase, or null if
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* this phase does not yield a key
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*
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* @exception InvalidKeyException if the given key is inappropriate for
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* this phase.
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* @exception IllegalStateException if this key agreement has not been
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* initialized.
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*/
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protected abstract Key engineDoPhase(Key key, boolean lastPhase)
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throws InvalidKeyException, IllegalStateException;
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/**
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* Generates the shared secret and returns it in a new buffer.
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*
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* <p>This method resets this <code>KeyAgreementSpi</code> object,
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* so that it
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* can be reused for further key agreements. Unless this key agreement is
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* reinitialized with one of the <code>engineInit</code> methods, the same
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* private information and algorithm parameters will be used for
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* subsequent key agreements.
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*
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* @return the new buffer with the shared secret
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*
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* @exception IllegalStateException if this key agreement has not been
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* completed yet
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*/
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protected abstract byte[] engineGenerateSecret()
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throws IllegalStateException;
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/**
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* Generates the shared secret, and places it into the buffer
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* <code>sharedSecret</code>, beginning at <code>offset</code> inclusive.
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*
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* <p>If the <code>sharedSecret</code> buffer is too small to hold the
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* result, a <code>ShortBufferException</code> is thrown.
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* In this case, this call should be repeated with a larger output buffer.
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*
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* <p>This method resets this <code>KeyAgreementSpi</code> object,
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* so that it
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* can be reused for further key agreements. Unless this key agreement is
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* reinitialized with one of the <code>engineInit</code> methods, the same
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* private information and algorithm parameters will be used for
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* subsequent key agreements.
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*
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* @param sharedSecret the buffer for the shared secret
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* @param offset the offset in <code>sharedSecret</code> where the
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* shared secret will be stored
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*
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* @return the number of bytes placed into <code>sharedSecret</code>
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*
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* @exception IllegalStateException if this key agreement has not been
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* completed yet
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* @exception ShortBufferException if the given output buffer is too small
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* to hold the secret
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*/
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protected abstract int engineGenerateSecret(byte[] sharedSecret,
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int offset)
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throws IllegalStateException, ShortBufferException;
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/**
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* Creates the shared secret and returns it as a secret key object
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* of the requested algorithm type.
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*
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* <p>This method resets this <code>KeyAgreementSpi</code> object,
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* so that it
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* can be reused for further key agreements. Unless this key agreement is
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* reinitialized with one of the <code>engineInit</code> methods, the same
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* private information and algorithm parameters will be used for
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* subsequent key agreements.
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*
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* @param algorithm the requested secret key algorithm
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*
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* @return the shared secret key
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*
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* @exception IllegalStateException if this key agreement has not been
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* completed yet
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* @exception NoSuchAlgorithmException if the requested secret key
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* algorithm is not available
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* @exception InvalidKeyException if the shared secret key material cannot
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* be used to generate a secret key of the requested algorithm type (e.g.,
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* the key material is too short)
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*/
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protected abstract SecretKey engineGenerateSecret(String algorithm)
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throws IllegalStateException, NoSuchAlgorithmException,
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InvalidKeyException;
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}
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