gcc/libjava/javax/crypto/KeyGeneratorSpi.java

/* KeyGeneratorSpi.java -- The key generator 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
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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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package javax.crypto;

import java.security.InvalidAlgorithmParameterException;
import java.security.SecureRandom;
import java.security.spec.AlgorithmParameterSpec;

/**
 * The <i>Service Provider Interface</i> (<b>SPI</b>) for the {@link
 * KeyGenerator} class.
 *
 * <p>Providers wishing to implement a key generator 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 generators is
 * <code>"KeyGenerator"</code>).
 *
 * @author Casey Marshall (csm@gnu.org)
 * @since 1.4
 * @see KeyGenerator
 */
public abstract class KeyGeneratorSpi
{

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

  /** Create a new key generator SPI. */
  public KeyGeneratorSpi()
  {
  }

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

  /**
   * Generate a key, returning it as a {@link SecretKey}.
   *
   * @return The generated key.
   */
  protected abstract SecretKey engineGenerateKey();

  /**
   * Initialize this key generator with parameters and a source of
   * randomness.
   *
   * @param params The parameters.
   * @param random The source of randomness.
   * @throws java.security.InvalidAlgorithmParameterException If the
   *         parameters are inappropriate for this instance.
   */
  protected abstract void engineInit(AlgorithmParameterSpec params,
                                     SecureRandom random)
    throws InvalidAlgorithmParameterException;

  /**
   * Initialize this key generator with a key size (in bits) and a
   * source of randomness.
   *
   * @param keySize The target key size, in bits.
   * @param random  The source of randomness.
   * @throws java.security.InvalidParameterException If the
   *         key size is illogical or unsupported.
   */
  protected abstract void engineInit(int keySize, SecureRandom random);

  /**
   * Initialize this key generator with a source of randomness; the
   * implementation should use reasonable default parameters (such as
   * generated key size).
   *
   * @param random The source of randomness.
   */
  protected abstract void engineInit(SecureRandom random);
}