1 /* 2 * Copyright (c) 1997, 2019, 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} 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} method), each provider must 41 * supply (and document) a default initialization. 42 * See the Keysize Restriction sections of the 43 * {@extLink security_guide_jdk_providers JDK Providers} 44 * document for information on the KeyPairGenerator defaults used by 45 * JDK providers. 46 * However, note that defaults may vary across different providers. 47 * Additionally, the default value for a provider may change in a future 48 * version. Therefore, it is recommended to explicitly initialize the 49 * KeyPairGenerator instead of relying on provider-specific defaults. 50 * 51 * @author Benjamin Renaud 52 * @since 1.2 53 * 54 * 55 * @see KeyPairGenerator 56 * @see java.security.spec.AlgorithmParameterSpec 57 */ 58 59 public abstract class KeyPairGeneratorSpi { 60 61 /** 62 * Initializes the key pair generator for a certain keysize, using 63 * the default parameter set. 64 * 65 * @param keysize the keysize. This is an 66 * algorithm-specific metric, such as modulus length, specified in 67 * number of bits. 68 * 69 * @param random the source of randomness for this generator. 70 * 71 * @throws InvalidParameterException if the {@code keysize} is not 72 * supported by this KeyPairGeneratorSpi object. 73 */ 74 public abstract void initialize(int keysize, SecureRandom random); 75 76 /** 77 * Initializes the key pair generator using the specified parameter 78 * set and user-provided source of randomness. 79 * 80 * <p>This concrete method has been added to this previously-defined 81 * abstract class. (For backwards compatibility, it cannot be abstract.) 82 * It may be overridden by a provider to initialize the key pair 83 * generator. Such an override 84 * is expected to throw an InvalidAlgorithmParameterException if 85 * a parameter is inappropriate for this key pair generator. 86 * If this method is not overridden, it always throws an 87 * UnsupportedOperationException. 88 * 89 * @param params the parameter set used to generate the keys. 90 * 91 * @param random the source of randomness for this generator. 92 * 93 * @throws InvalidAlgorithmParameterException if the given parameters 94 * are inappropriate for this key pair generator. 95 * 96 * @since 1.2 97 */ 98 public void initialize(AlgorithmParameterSpec params, 99 SecureRandom random) 100 throws InvalidAlgorithmParameterException { 101 throw new UnsupportedOperationException(); 102 } 103 104 /** 105 * Generates a key pair. Unless an initialization method is called 106 * using a KeyPairGenerator interface, algorithm-specific defaults 107 * will be used. This will generate a new key pair every time it 108 * is called. 109 * 110 * @return the newly generated {@code KeyPair} 111 */ 112 public abstract KeyPair generateKeyPair(); 113 }