001/* KeyGenerator.java -- Interface to a symmetric key generator. 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 gnu.java.security.Engine; 042 043import java.lang.reflect.InvocationTargetException; 044import java.security.InvalidAlgorithmParameterException; 045import java.security.NoSuchAlgorithmException; 046import java.security.NoSuchProviderException; 047import java.security.Provider; 048import java.security.SecureRandom; 049import java.security.Security; 050import java.security.spec.AlgorithmParameterSpec; 051 052/** 053 * A generic producer of keys for symmetric cryptography. The keys 054 * returned may be simple wrappers around byte arrays, or, if the 055 * target cipher requires them, more complex objects. 056 * 057 * @author Casey Marshall (csm@gnu.org) 058 * @since 1.4 059 * @see Cipher 060 * @see Mac 061 */ 062public class KeyGenerator 063{ 064 065 // Constants and fields. 066 // ------------------------------------------------------------------------ 067 068 private static final String SERVICE = "KeyGenerator"; 069 070 /** The underlying generator implementation. */ 071 private KeyGeneratorSpi kgSpi; 072 073 /** The provider of the implementation. */ 074 private Provider provider; 075 076 /** The name of the algorithm. */ 077 private String algorithm; 078 079 // Constructor. 080 // ------------------------------------------------------------------------ 081 082 /** 083 * Create a new key generator. 084 * 085 * @param kgSpi The underlying generator. 086 * @param provider The provider of this implementation. 087 * @param algorithm The algorithm's name. 088 */ 089 protected KeyGenerator(KeyGeneratorSpi kgSpi, Provider provider, 090 String algorithm) 091 { 092 this.kgSpi = kgSpi; 093 this.provider = provider; 094 this.algorithm = algorithm; 095 } 096 097 /** 098 * Create a new key generator, returning the first available implementation. 099 * 100 * @param algorithm The generator algorithm name. 101 * @throws NoSuchAlgorithmException If the specified algorithm does not exist. 102 * @throws IllegalArgumentException if <code>algorithm</code> is 103 * <code>null</code> or is an empty string. 104 */ 105 public static final KeyGenerator getInstance(String algorithm) 106 throws NoSuchAlgorithmException 107 { 108 Provider[] p = Security.getProviders(); 109 NoSuchAlgorithmException lastException = null; 110 for (int i = 0; i < p.length; i++) 111 try 112 { 113 return getInstance(algorithm, p[i]); 114 } 115 catch (NoSuchAlgorithmException x) 116 { 117 lastException = x; 118 } 119 if (lastException != null) 120 throw lastException; 121 throw new NoSuchAlgorithmException(algorithm); 122 } 123 124 /** 125 * Create a new key generator from the named provider. 126 * 127 * @param algorithm The generator algorithm name. 128 * @param provider The name of the provider to use. 129 * @return An appropriate key generator, if found. 130 * @throws NoSuchAlgorithmException If the specified algorithm is not 131 * implemented by the named provider. 132 * @throws NoSuchProviderException If the named provider does not exist. 133 * @throws IllegalArgumentException if either <code>algorithm</code> or 134 * <code>provider</code> is <code>null</code>, or if 135 * <code>algorithm</code> is an empty string. 136 */ 137 public static final KeyGenerator getInstance(String algorithm, String provider) 138 throws NoSuchAlgorithmException, NoSuchProviderException 139 { 140 if (provider == null) 141 throw new IllegalArgumentException("provider MUST NOT be null"); 142 Provider p = Security.getProvider(provider); 143 if (p == null) 144 throw new NoSuchProviderException(provider); 145 return getInstance(algorithm, p); 146 } 147 148 /** 149 * Create a new key generator from the supplied provider. 150 * 151 * @param algorithm The generator algorithm name. 152 * @param provider The provider to use. 153 * @return An appropriate key generator, if found. 154 * @throws NoSuchAlgorithmException If the specified algorithm is not 155 * implemented by the provider. 156 * @throws IllegalArgumentException if either <code>algorithm</code> or 157 * <code>provider</code> is <code>null</code>, or if 158 * <code>algorithm</code> is an empty string. 159 */ 160 public static final KeyGenerator getInstance(String algorithm, 161 Provider provider) 162 throws NoSuchAlgorithmException 163 { 164 StringBuilder sb = new StringBuilder("KeyGenerator algorithm [") 165 .append(algorithm).append("] from provider[") 166 .append(provider).append("] could not be created"); 167 Throwable cause; 168 try 169 { 170 Object spi = Engine.getInstance(SERVICE, algorithm, provider); 171 KeyGenerator instance = new KeyGenerator((KeyGeneratorSpi) spi, 172 provider, 173 algorithm); 174 instance.init(new SecureRandom()); 175 return instance; 176 } 177 catch (InvocationTargetException x) 178 { 179 cause = x.getCause(); 180 if (cause instanceof NoSuchAlgorithmException) 181 throw (NoSuchAlgorithmException) cause; 182 if (cause == null) 183 cause = x; 184 } 185 catch (ClassCastException x) 186 { 187 cause = x; 188 } 189 NoSuchAlgorithmException x = new NoSuchAlgorithmException(sb.toString()); 190 x.initCause(cause); 191 throw x; 192 } 193 194 /** 195 * Generate a key. 196 * 197 * @return The new key. 198 */ 199 public final SecretKey generateKey() 200 { 201 return kgSpi.engineGenerateKey(); 202 } 203 204 /** 205 * Return the name of this key generator. 206 * 207 * @return The algorithm name. 208 */ 209 public final String getAlgorithm() 210 { 211 return algorithm; 212 } 213 214 /** 215 * Return the provider of the underlying implementation. 216 * 217 * @return The provider. 218 */ 219 public final Provider getProvider() 220 { 221 return provider; 222 } 223 224 /** 225 * Initialize this key generator with a set of parameters; the 226 * highest-priority {@link java.security.SecureRandom} implementation 227 * will be used. 228 * 229 * @param params The algorithm parameters. 230 * @throws java.security.InvalidAlgorithmParameterException If the 231 * supplied parameters are inapproprate. 232 */ 233 public final void init(AlgorithmParameterSpec params) 234 throws InvalidAlgorithmParameterException 235 { 236 init(params, new SecureRandom()); 237 } 238 239 /** 240 * Initialize this key generator with a set of parameters and a source 241 * of randomness. 242 * 243 * @param params The algorithm parameters. 244 * @param random The source of randomness. 245 * @throws java.security.InvalidAlgorithmParameterException If the 246 * supplied parameters are inapproprate. 247 */ 248 public final void init(AlgorithmParameterSpec params, SecureRandom random) 249 throws InvalidAlgorithmParameterException 250 { 251 kgSpi.engineInit(params, random); 252 } 253 254 /** 255 * Initialize this key generator with a key size (in bits); the 256 * highest-priority {@link java.security.SecureRandom} implementation 257 * will be used. 258 * 259 * @param keySize The target key size, in bits. 260 * @throws java.security.InvalidParameterException If the 261 * key size is unsupported. 262 */ 263 public final void init(int keySize) 264 { 265 init(keySize, new SecureRandom()); 266 } 267 268 /** 269 * Initialize this key generator with a key size (in bits) and a 270 * source of randomness. 271 * 272 * @param keySize The target key size, in bits. 273 * @param random The source of randomness. 274 * @throws java.security.InvalidAlgorithmParameterException If the 275 * key size is unsupported. 276 */ 277 public final void init(int keySize, SecureRandom random) 278 { 279 kgSpi.engineInit(keySize, random); 280 } 281 282 /** 283 * Initialize this key generator with a source of randomness. The 284 * implementation-specific default parameters (such as key size) will 285 * be used. 286 * 287 * @param random The source of randomness. 288 */ 289 public final void init(SecureRandom random) 290 { 291 kgSpi.engineInit(random); 292 } 293}