001/* KeyAgreementSpi.java -- The key agreement service provider interface.
002   Copyright (C) 2004  Free Software Foundation, Inc.
003
004This file is part of GNU Classpath.
005
006GNU Classpath is free software; you can redistribute it and/or modify
007it under the terms of the GNU General Public License as published by
008the Free Software Foundation; either version 2, or (at your option)
009any later version.
010
011GNU Classpath is distributed in the hope that it will be useful, but
012WITHOUT ANY WARRANTY; without even the implied warranty of
013MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
014General Public License for more details.
015
016You should have received a copy of the GNU General Public License
017along with GNU Classpath; see the file COPYING.  If not, write to the
018Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
01902110-1301 USA.
020
021Linking this library statically or dynamically with other modules is
022making a combined work based on this library.  Thus, the terms and
023conditions of the GNU General Public License cover the whole
024combination.
025
026As a special exception, the copyright holders of this library give you
027permission to link this library with independent modules to produce an
028executable, regardless of the license terms of these independent
029modules, and to copy and distribute the resulting executable under
030terms of your choice, provided that you also meet, for each linked
031independent module, the terms and conditions of the license of that
032module.  An independent module is a module which is not derived from
033or based on this library.  If you modify this library, you may extend
034this exception to your version of the library, but you are not
035obligated to do so.  If you do not wish to do so, delete this
036exception statement from your version. */
037
038
039package javax.crypto;
040
041import java.security.InvalidAlgorithmParameterException;
042import java.security.InvalidKeyException;
043import java.security.Key;
044import java.security.NoSuchAlgorithmException;
045import java.security.SecureRandom;
046import 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 */
063public 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}