1 /*
   2  * Copyright (c) 1997, 1999, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 
  26 package java.security;
  27 
  28 import java.security.spec.AlgorithmParameterSpec;
  29 
  30 /**
  31  * <p> This class defines the <i>Service Provider Interface</i> (<b>SPI</b>)
  32  * for the <code>KeyPairGenerator</code> class, which is used to generate
  33  * pairs of public and private keys.
  34  *
  35  * <p> All the abstract methods in this class must be implemented by each
  36  * cryptographic service provider who wishes to supply the implementation
  37  * of a key pair generator for a particular algorithm.
  38  *
  39  * <p> In case the client does not explicitly initialize the KeyPairGenerator
  40  * (via a call to an <code>initialize</code> method), each provider must
  41  * supply (and document) a default initialization.
  42  * For example, the <i>Sun</i> provider uses a default modulus size (keysize)
  43  * of 1024 bits.
  44  *
  45  * @author Benjamin Renaud
  46  *
  47  *
  48  * @see KeyPairGenerator
  49  * @see java.security.spec.AlgorithmParameterSpec
  50  */
  51 
  52 public abstract class KeyPairGeneratorSpi {
  53 
  54     /**
  55      * Initializes the key pair generator for a certain keysize, using
  56      * the default parameter set.
  57      *
  58      * @param keysize the keysize. This is an
  59      * algorithm-specific metric, such as modulus length, specified in
  60      * number of bits.
  61      *
  62      * @param random the source of randomness for this generator.
  63      *
  64      * @exception InvalidParameterException if the <code>keysize</code> is not
  65      * supported by this KeyPairGeneratorSpi object.
  66      */
  67     public abstract void initialize(int keysize, SecureRandom random);
  68 
  69     /**
  70      * Initializes the key pair generator using the specified parameter
  71      * set and user-provided source of randomness.
  72      *
  73      * <p>This concrete method has been added to this previously-defined
  74      * abstract class. (For backwards compatibility, it cannot be abstract.)
  75      * It may be overridden by a provider to initialize the key pair
  76      * generator. Such an override
  77      * is expected to throw an InvalidAlgorithmParameterException if
  78      * a parameter is inappropriate for this key pair generator.
  79      * If this method is not overridden, it always throws an
  80      * UnsupportedOperationException.
  81      *
  82      * @param params the parameter set used to generate the keys.
  83      *
  84      * @param random the source of randomness for this generator.
  85      *
  86      * @exception InvalidAlgorithmParameterException if the given parameters
  87      * are inappropriate for this key pair generator.
  88      *
  89      * @since 1.2
  90      */
  91     public void initialize(AlgorithmParameterSpec params,
  92                            SecureRandom random)
  93         throws InvalidAlgorithmParameterException {
  94             throw new UnsupportedOperationException();
  95     }
  96 
  97     /**
  98      * Generates a key pair. Unless an initialization method is called
  99      * using a KeyPairGenerator interface, algorithm-specific defaults
 100      * will be used. This will generate a new key pair every time it
 101      * is called.
 102      *
 103      * @return the newly generated <tt>KeyPair</tt>
 104      */
 105     public abstract KeyPair generateKeyPair();
 106 }