001    /* KeyAgreementSpi.java -- The key agreement service provider interface.
002       Copyright (C) 2004  Free Software Foundation, Inc.
003    
004    This file is part of GNU Classpath.
005    
006    GNU Classpath is free software; you can redistribute it and/or modify
007    it under the terms of the GNU General Public License as published by
008    the Free Software Foundation; either version 2, or (at your option)
009    any later version.
010    
011    GNU Classpath is distributed in the hope that it will be useful, but
012    WITHOUT ANY WARRANTY; without even the implied warranty of
013    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
014    General Public License for more details.
015    
016    You should have received a copy of the GNU General Public License
017    along with GNU Classpath; see the file COPYING.  If not, write to the
018    Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
019    02110-1301 USA.
020    
021    Linking this library statically or dynamically with other modules is
022    making a combined work based on this library.  Thus, the terms and
023    conditions of the GNU General Public License cover the whole
024    combination.
025    
026    As a special exception, the copyright holders of this library give you
027    permission to link this library with independent modules to produce an
028    executable, regardless of the license terms of these independent
029    modules, and to copy and distribute the resulting executable under
030    terms of your choice, provided that you also meet, for each linked
031    independent module, the terms and conditions of the license of that
032    module.  An independent module is a module which is not derived from
033    or based on this library.  If you modify this library, you may extend
034    this exception to your version of the library, but you are not
035    obligated to do so.  If you do not wish to do so, delete this
036    exception statement from your version. */
037    
038    
039    package javax.crypto;
040    
041    import java.security.InvalidAlgorithmParameterException;
042    import java.security.InvalidKeyException;
043    import java.security.Key;
044    import java.security.NoSuchAlgorithmException;
045    import java.security.SecureRandom;
046    import java.security.spec.AlgorithmParameterSpec;
047    
048    /**
049     * This is the <i>Service Provider Interface</i> (<b>SPI</b>) for the
050     * {@link javax.crypto.KeyAgreement} class.
051     *
052     * <p>Providers wishing to implement a key agreement algorithm must
053     * subclass this and provide an appropriate implementation for all the
054     * abstract methods below, and provide an appropriate entry in the
055     * master {@link java.security.Provider} class (the service name for key
056     * agreement algorithms is <code>"KeyAgreement"</code>).
057     *
058     * @author Casey Marshall (csm@gnu.org)
059     * @since 1.4
060     * @see KeyAgreement
061     * @see SecretKey
062     */
063    public abstract class KeyAgreementSpi
064    {
065    
066      // Constructor.
067      // ------------------------------------------------------------------------
068    
069      /**
070       * Create a new KeyAgreementSpi instance.
071       */
072      public KeyAgreementSpi()
073      {
074      }
075    
076      // Abstract instance methods.
077      // ------------------------------------------------------------------------
078    
079      /**
080       * Do a phase in the key agreement.
081       *
082       * @param key The key to use for this phase.
083       * @param lastPhase <code>true</code> if this call should be the last
084       *        phase.
085       * @return The intermediate result, or <code>null</code> if there is
086       *         no intermediate result.
087       * @throws java.lang.IllegalStateException If this instance has not
088       *         been initialized.
089       * @throws java.security.InvalidKeyException If the supplied key is
090       *         not appropriate.
091       */
092      protected abstract Key engineDoPhase(Key key, boolean lastPhase)
093        throws IllegalStateException, InvalidKeyException;
094    
095      /**
096       * Generate the shared secret in a new byte array.
097       *
098       * @return The shared secret in a new byte array.
099       * @throws java.lang.IllegalStateException If this key agreement is
100       *         not ready to generate the secret.
101       */
102      protected abstract byte[] engineGenerateSecret()
103        throws IllegalStateException;
104    
105      /**
106       * Generate the shared secret, storing it into the specified array.
107       *
108       * @param sharedSecret The byte array in which to store the secret.
109       * @param offset       The offset into the byte array to start.
110       * @return The size of the shared secret.
111       * @throws java.lang.IllegalStateException If this key agreement is
112       *         not ready to generate the secret.
113       * @throws javax.crypto.ShortBufferException If there is not enough
114       *         space in the supplied array for the shared secret.
115       */
116      protected abstract int engineGenerateSecret(byte[] sharedSecret, int offset)
117        throws IllegalStateException, ShortBufferException;
118    
119      /**
120       * Generate the shared secret and return it as a {@link SecretKey}.
121       *
122       * @param algorithm The algorithm with which to generate the secret key.
123       * @return The shared secret as a secret key.
124       * @throws java.lang.IllegalStateException If this key agreement is
125       *         not ready to generate the secret.
126       * @throws java.security.InvalidKeyException If the shared secret
127       *         cannot be made into a {@link SecretKey}.
128       * @throws java.security.NoSuchAlgorithmException If
129       *         <code>algorithm</code> cannot be found.
130       */
131      protected abstract SecretKey engineGenerateSecret(String algorithm)
132        throws IllegalStateException, InvalidKeyException, NoSuchAlgorithmException;
133    
134      /**
135       * Initialize this key agreement with a key, parameters, and source of
136       * randomness.
137       *
138       * @param key    The key to initialize with, usually a private key.
139       * @param params The parameters to initialize with.
140       * @param random The source of randomness to use.
141       * @throws java.security.InvalidAlgorithmParameterException If the
142       *         supplied parameters are inappropriate.
143       * @throws java.security.InvalidKeyException If the supplied key is
144       *         inappropriate.
145       */
146      protected abstract void engineInit(Key key, AlgorithmParameterSpec params,
147                                         SecureRandom random)
148        throws InvalidAlgorithmParameterException, InvalidKeyException;
149    
150      /**
151       * Initialize this key agreement with a key and source of randomness.
152       *
153       * @param key    The key to initialize with, usually a private key.
154       * @param random The source of randomness to use.
155       * @throws java.security.InvalidKeyException If the supplied key is
156       *         inappropriate.
157       */
158      protected abstract void engineInit(Key key, SecureRandom random)
159        throws InvalidKeyException;
160    }