1 /* 2 * Copyright (c) 1997, 2020, 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.KeySpec; 29 import java.security.spec.InvalidKeySpecException; 30 31 /** 32 * This class defines the <i>Service Provider Interface</i> (<b>SPI</b>) 33 * for the {@code KeyFactory} class. 34 * All the abstract methods in this class must be implemented by each 35 * cryptographic service provider who wishes to supply the implementation 36 * of a key factory for a particular algorithm. 37 * 38 * <P> Key factories are used to convert <I>keys</I> (opaque 39 * cryptographic keys of type {@code Key}) into <I>key specifications</I> 40 * (transparent representations of the underlying key material), and vice 41 * versa. 42 * 43 * <P> Key factories are bi-directional. That is, they allow you to build an 44 * opaque key object from a given key specification (key material), or to 45 * retrieve the underlying key material of a key object in a suitable format. 46 * 47 * <P> Multiple compatible key specifications may exist for the same key. 48 * For example, a DSA public key may be specified using 49 * {@code DSAPublicKeySpec} or 50 * {@code X509EncodedKeySpec}. A key factory can be used to translate 51 * between compatible key specifications. 52 * 53 * <P> A provider should document all the key specifications supported by its 54 * key factory. 55 * 56 * @author Jan Luehe 57 * 58 * 59 * @see KeyFactory 60 * @see Key 61 * @see PublicKey 62 * @see PrivateKey 63 * @see java.security.spec.KeySpec 64 * @see java.security.spec.DSAPublicKeySpec 65 * @see java.security.spec.X509EncodedKeySpec 66 * 67 * @since 1.2 68 */ 69 70 public abstract class KeyFactorySpi { 71 72 /** 73 * Constructor for subclasses to call. 74 */ KeyFactorySpi()75 public KeyFactorySpi() {} 76 77 /** 78 * Generates a public key object from the provided key 79 * specification (key material). 80 * 81 * @param keySpec the specification (key material) of the public key. 82 * 83 * @return the public key. 84 * 85 * @throws InvalidKeySpecException if the given key specification 86 * is inappropriate for this key factory to produce a public key. 87 */ engineGeneratePublic(KeySpec keySpec)88 protected abstract PublicKey engineGeneratePublic(KeySpec keySpec) 89 throws InvalidKeySpecException; 90 91 /** 92 * Generates a private key object from the provided key 93 * specification (key material). 94 * 95 * @param keySpec the specification (key material) of the private key. 96 * 97 * @return the private key. 98 * 99 * @throws InvalidKeySpecException if the given key specification 100 * is inappropriate for this key factory to produce a private key. 101 */ engineGeneratePrivate(KeySpec keySpec)102 protected abstract PrivateKey engineGeneratePrivate(KeySpec keySpec) 103 throws InvalidKeySpecException; 104 105 /** 106 * Returns a specification (key material) of the given key 107 * object. 108 * {@code keySpec} identifies the specification class in which 109 * the key material should be returned. It could, for example, be 110 * {@code DSAPublicKeySpec.class}, to indicate that the 111 * key material should be returned in an instance of the 112 * {@code DSAPublicKeySpec} class. 113 * 114 * @param <T> the type of the key specification to be returned 115 * 116 * @param key the key. 117 * 118 * @param keySpec the specification class in which 119 * the key material should be returned. 120 * 121 * @return the underlying key specification (key material) in an instance 122 * of the requested specification class. 123 * 124 * @throws InvalidKeySpecException if the requested key specification is 125 * inappropriate for the given key, or the given key cannot be dealt with 126 * (e.g., the given key has an unrecognized format). 127 */ 128 protected abstract <T extends KeySpec> engineGetKeySpec(Key key, Class<T> keySpec)129 T engineGetKeySpec(Key key, Class<T> keySpec) 130 throws InvalidKeySpecException; 131 132 /** 133 * Translates a key object, whose provider may be unknown or 134 * potentially untrusted, into a corresponding key object of this key 135 * factory. 136 * 137 * @param key the key whose provider is unknown or untrusted. 138 * 139 * @return the translated key. 140 * 141 * @throws InvalidKeyException if the given key cannot be processed 142 * by this key factory. 143 */ engineTranslateKey(Key key)144 protected abstract Key engineTranslateKey(Key key) 145 throws InvalidKeyException; 146 147 } 148