gcc/libjava/javax/crypto/KeyAgreementSpi.java

/* KeyAgreementSpi.java -- The key agreement service provider interface.
   Copyright (C) 2004  Free Software Foundation, Inc.

This file is part of GNU Classpath.

GNU Classpath is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.

GNU Classpath is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
General Public License for more details.

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Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA.

Linking this library statically or dynamically with other modules is
making a combined work based on this library.  Thus, the terms and
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combination.

As a special exception, the copyright holders of this library give you
permission to link this library with independent modules to produce an
executable, regardless of the license terms of these independent
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terms of your choice, provided that you also meet, for each linked
independent module, the terms and conditions of the license of that
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this exception to your version of the library, but you are not
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exception statement from your version. */


package javax.crypto;

import java.security.InvalidAlgorithmParameterException;
import java.security.InvalidKeyException;
import java.security.Key;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
import java.security.spec.AlgorithmParameterSpec;

/**
 * This is the <i>Service Provider Interface</i> (<b>SPI</b>) for the
 * {@link javax.crypto.KeyAgreement} class.
 *
 * <p>Providers wishing to implement a key agreement algorithm must
 * subclass this and provide an appropriate implementation for all the
 * abstract methods below, and provide an appropriate entry in the
 * master {@link java.security.Provider} class (the service name for key
 * agreement algorithms is <code>"KeyAgreement"</code>).
 *
 * @author Casey Marshall (csm@gnu.org)
 * @since 1.4
 * @see KeyAgreement
 * @see SecretKey
 */
public abstract class KeyAgreementSpi
{

  // Constructor.
  // ------------------------------------------------------------------------

  /**
   * Create a new KeyAgreementSpi instance.
   */
  public KeyAgreementSpi()
  {
  }

  // Abstract instance methods.
  // ------------------------------------------------------------------------

  /**
   * Do a phase in the key agreement.
   *
   * @param key The key to use for this phase.
   * @param lastPhase <code>true</code> if this call should be the last
   *        phase.
   * @return The intermediate result, or <code>null</code> if there is
   *         no intermediate result.
   * @throws java.lang.IllegalStateException If this instance has not
   *         been initialized.
   * @throws java.security.InvalidKeyException If the supplied key is
   *         not appropriate.
   */
  protected abstract Key engineDoPhase(Key key, boolean lastPhase)
    throws IllegalStateException, InvalidKeyException;

  /**
   * Generate the shared secret in a new byte array.
   *
   * @return The shared secret in a new byte array.
   * @throws java.lang.IllegalStateException If this key agreement is
   *         not ready to generate the secret.
   */
  protected abstract byte[] engineGenerateSecret()
    throws IllegalStateException;

  /**
   * Generate the shared secret, storing it into the specified array.
   *
   * @param sharedSecret The byte array in which to store the secret.
   * @param offset       The offset into the byte array to start.
   * @return The size of the shared secret.
   * @throws java.lang.IllegalStateException If this key agreement is
   *         not ready to generate the secret.
   * @throws javax.crypto.ShortBufferException If there is not enough
   *         space in the supplied array for the shared secret.
   */
  protected abstract int engineGenerateSecret(byte[] sharedSecret, int offset)
    throws IllegalStateException, ShortBufferException;

  /**
   * Generate the shared secret and return it as a {@link SecretKey}.
   *
   * @param algorithm The algorithm with which to generate the secret key.
   * @return The shared secret as a secret key.
   * @throws java.lang.IllegalStateException If this key agreement is
   *         not ready to generate the secret.
   * @throws java.security.InvalidKeyException If the shared secret
   *         cannot be made into a {@link SecretKey}.
   * @throws java.security.NoSuchAlgorithmException If
   *         <code>algorithm</code> cannot be found.
   */
  protected abstract SecretKey engineGenerateSecret(String algorithm)
    throws IllegalStateException, InvalidKeyException, NoSuchAlgorithmException;

  /**
   * Initialize this key agreement with a key, parameters, and source of
   * randomness.
   *
   * @param key    The key to initialize with, usually a private key.
   * @param params The parameters to initialize with.
   * @param random The source of randomness to use.
   * @throws java.security.InvalidAlgorithmParameterException If the
   *         supplied parameters are inappropriate.
   * @throws java.security.InvalidKeyException If the supplied key is
   *         inappropriate.
   */
  protected abstract void engineInit(Key key, AlgorithmParameterSpec params,
                                     SecureRandom random)
    throws InvalidAlgorithmParameterException, InvalidKeyException;

  /**
   * Initialize this key agreement with a key and source of randomness.
   *
   * @param key    The key to initialize with, usually a private key.
   * @param random The source of randomness to use.
   * @throws java.security.InvalidKeyException If the supplied key is
   *         inappropriate.
   */
  protected abstract void engineInit(Key key, SecureRandom random)
    throws InvalidKeyException;
}