001/* KeyAgreementSpi.java -- The key agreement service provider interface. 002 Copyright (C) 2004 Free Software Foundation, Inc. 003 004This file is part of GNU Classpath. 005 006GNU Classpath is free software; you can redistribute it and/or modify 007it under the terms of the GNU General Public License as published by 008the Free Software Foundation; either version 2, or (at your option) 009any later version. 010 011GNU Classpath is distributed in the hope that it will be useful, but 012WITHOUT ANY WARRANTY; without even the implied warranty of 013MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 014General Public License for more details. 015 016You should have received a copy of the GNU General Public License 017along with GNU Classpath; see the file COPYING. If not, write to the 018Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 01902110-1301 USA. 020 021Linking this library statically or dynamically with other modules is 022making a combined work based on this library. Thus, the terms and 023conditions of the GNU General Public License cover the whole 024combination. 025 026As a special exception, the copyright holders of this library give you 027permission to link this library with independent modules to produce an 028executable, regardless of the license terms of these independent 029modules, and to copy and distribute the resulting executable under 030terms of your choice, provided that you also meet, for each linked 031independent module, the terms and conditions of the license of that 032module. An independent module is a module which is not derived from 033or based on this library. If you modify this library, you may extend 034this exception to your version of the library, but you are not 035obligated to do so. If you do not wish to do so, delete this 036exception statement from your version. */ 037 038 039package javax.crypto; 040 041import java.security.InvalidAlgorithmParameterException; 042import java.security.InvalidKeyException; 043import java.security.Key; 044import java.security.NoSuchAlgorithmException; 045import java.security.SecureRandom; 046import java.security.spec.AlgorithmParameterSpec; 047 048/** 049 * This is the <i>Service Provider Interface</i> (<b>SPI</b>) for the 050 * {@link javax.crypto.KeyAgreement} class. 051 * 052 * <p>Providers wishing to implement a key agreement algorithm must 053 * subclass this and provide an appropriate implementation for all the 054 * abstract methods below, and provide an appropriate entry in the 055 * master {@link java.security.Provider} class (the service name for key 056 * agreement algorithms is <code>"KeyAgreement"</code>). 057 * 058 * @author Casey Marshall (csm@gnu.org) 059 * @since 1.4 060 * @see KeyAgreement 061 * @see SecretKey 062 */ 063public abstract class KeyAgreementSpi 064{ 065 066 // Constructor. 067 // ------------------------------------------------------------------------ 068 069 /** 070 * Create a new KeyAgreementSpi instance. 071 */ 072 public KeyAgreementSpi() 073 { 074 } 075 076 // Abstract instance methods. 077 // ------------------------------------------------------------------------ 078 079 /** 080 * Do a phase in the key agreement. 081 * 082 * @param key The key to use for this phase. 083 * @param lastPhase <code>true</code> if this call should be the last 084 * phase. 085 * @return The intermediate result, or <code>null</code> if there is 086 * no intermediate result. 087 * @throws java.lang.IllegalStateException If this instance has not 088 * been initialized. 089 * @throws java.security.InvalidKeyException If the supplied key is 090 * not appropriate. 091 */ 092 protected abstract Key engineDoPhase(Key key, boolean lastPhase) 093 throws IllegalStateException, InvalidKeyException; 094 095 /** 096 * Generate the shared secret in a new byte array. 097 * 098 * @return The shared secret in a new byte array. 099 * @throws java.lang.IllegalStateException If this key agreement is 100 * not ready to generate the secret. 101 */ 102 protected abstract byte[] engineGenerateSecret() 103 throws IllegalStateException; 104 105 /** 106 * Generate the shared secret, storing it into the specified array. 107 * 108 * @param sharedSecret The byte array in which to store the secret. 109 * @param offset The offset into the byte array to start. 110 * @return The size of the shared secret. 111 * @throws java.lang.IllegalStateException If this key agreement is 112 * not ready to generate the secret. 113 * @throws javax.crypto.ShortBufferException If there is not enough 114 * space in the supplied array for the shared secret. 115 */ 116 protected abstract int engineGenerateSecret(byte[] sharedSecret, int offset) 117 throws IllegalStateException, ShortBufferException; 118 119 /** 120 * Generate the shared secret and return it as a {@link SecretKey}. 121 * 122 * @param algorithm The algorithm with which to generate the secret key. 123 * @return The shared secret as a secret key. 124 * @throws java.lang.IllegalStateException If this key agreement is 125 * not ready to generate the secret. 126 * @throws java.security.InvalidKeyException If the shared secret 127 * cannot be made into a {@link SecretKey}. 128 * @throws java.security.NoSuchAlgorithmException If 129 * <code>algorithm</code> cannot be found. 130 */ 131 protected abstract SecretKey engineGenerateSecret(String algorithm) 132 throws IllegalStateException, InvalidKeyException, NoSuchAlgorithmException; 133 134 /** 135 * Initialize this key agreement with a key, parameters, and source of 136 * randomness. 137 * 138 * @param key The key to initialize with, usually a private key. 139 * @param params The parameters to initialize with. 140 * @param random The source of randomness to use. 141 * @throws java.security.InvalidAlgorithmParameterException If the 142 * supplied parameters are inappropriate. 143 * @throws java.security.InvalidKeyException If the supplied key is 144 * inappropriate. 145 */ 146 protected abstract void engineInit(Key key, AlgorithmParameterSpec params, 147 SecureRandom random) 148 throws InvalidAlgorithmParameterException, InvalidKeyException; 149 150 /** 151 * Initialize this key agreement with a key and source of randomness. 152 * 153 * @param key The key to initialize with, usually a private key. 154 * @param random The source of randomness to use. 155 * @throws java.security.InvalidKeyException If the supplied key is 156 * inappropriate. 157 */ 158 protected abstract void engineInit(Key key, SecureRandom random) 159 throws InvalidKeyException; 160}