001 /* AlgorithmParameterGenerator.java --- Algorithm Parameter Generator 002 Copyright (C) 1999, 2003, 2004 Free Software Foundation, Inc. 003 004 This file is part of GNU Classpath. 005 006 GNU Classpath is free software; you can redistribute it and/or modify 007 it under the terms of the GNU General Public License as published by 008 the Free Software Foundation; either version 2, or (at your option) 009 any later version. 010 011 GNU Classpath is distributed in the hope that it will be useful, but 012 WITHOUT ANY WARRANTY; without even the implied warranty of 013 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 014 General Public License for more details. 015 016 You should have received a copy of the GNU General Public License 017 along with GNU Classpath; see the file COPYING. If not, write to the 018 Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 019 02110-1301 USA. 020 021 Linking this library statically or dynamically with other modules is 022 making a combined work based on this library. Thus, the terms and 023 conditions of the GNU General Public License cover the whole 024 combination. 025 026 As a special exception, the copyright holders of this library give you 027 permission to link this library with independent modules to produce an 028 executable, regardless of the license terms of these independent 029 modules, and to copy and distribute the resulting executable under 030 terms of your choice, provided that you also meet, for each linked 031 independent module, the terms and conditions of the license of that 032 module. An independent module is a module which is not derived from 033 or based on this library. If you modify this library, you may extend 034 this exception to your version of the library, but you are not 035 obligated to do so. If you do not wish to do so, delete this 036 exception statement from your version. */ 037 038 039 package java.security; 040 041 import gnu.java.lang.CPStringBuilder; 042 043 import gnu.java.security.Engine; 044 045 import java.lang.reflect.InvocationTargetException; 046 import java.security.spec.AlgorithmParameterSpec; 047 048 /** 049 * <code>AlgorithmParameterGenerator</code> is used to generate algorithm 050 * parameters for specified algorithms. 051 * 052 * <p>In case the client does not explicitly initialize the 053 * <code>AlgorithmParameterGenerator</code> (via a call to an 054 * <code>init()</code> method), each provider must supply (and document) a 055 * default initialization. For example, the <b>GNU</b> provider uses a default 056 * modulus prime size of <code>1024</code> bits for the generation of <i>DSA</i> 057 * parameters. 058 * 059 * @author Mark Benvenuto 060 * @since 1.2 061 * @see AlgorithmParameters 062 * @see AlgorithmParameterSpec 063 */ 064 public class AlgorithmParameterGenerator 065 { 066 /** Service name for algorithm parameter generators. */ 067 private static final String ALGORITHM_PARAMETER_GENERATOR = 068 "AlgorithmParameterGenerator"; 069 070 private AlgorithmParameterGeneratorSpi paramGenSpi; 071 private Provider provider; 072 private String algorithm; 073 074 /** 075 * Constructs a new instance of <code>AlgorithmParameterGenerator</code>. 076 * 077 * @param paramGenSpi 078 * the generator to use. 079 * @param provider 080 * the provider to use. 081 * @param algorithm 082 * the algorithm to use. 083 */ 084 protected AlgorithmParameterGenerator(AlgorithmParameterGeneratorSpi 085 paramGenSpi, Provider provider, 086 String algorithm) 087 { 088 this.paramGenSpi = paramGenSpi; 089 this.provider = provider; 090 this.algorithm = algorithm; 091 } 092 093 /** @return the name of the algorithm. */ 094 public final String getAlgorithm() 095 { 096 return algorithm; 097 } 098 099 /** 100 * Returns a new <code>AlgorithmParameterGenerator</code> instance which 101 * generates algorithm parameters for the specified algorithm. 102 * 103 * @param algorithm the name of algorithm to use. 104 * @return the new instance. 105 * @throws NoSuchAlgorithmException if <code>algorithm</code> is not 106 * implemented by any provider. 107 * @throws IllegalArgumentException if <code>algorithm</code> is 108 * <code>null</code> or is an empty string. 109 */ 110 public static AlgorithmParameterGenerator getInstance(String algorithm) 111 throws NoSuchAlgorithmException 112 { 113 Provider[] p = Security.getProviders(); 114 NoSuchAlgorithmException lastException = null; 115 for (int i = 0; i < p.length; i++) 116 try 117 { 118 return getInstance(algorithm, p[i]); 119 } 120 catch (NoSuchAlgorithmException x) 121 { 122 lastException = x; 123 } 124 if (lastException != null) 125 throw lastException; 126 throw new NoSuchAlgorithmException(algorithm); 127 } 128 129 /** 130 * Returns a new <code>AlgorithmParameterGenerator</code> instance which 131 * generates algorithm parameters for the specified algorithm. 132 * 133 * @param algorithm the name of algorithm to use. 134 * @param provider the name of the {@link Provider} to use. 135 * @return the new instance. 136 * @throws NoSuchAlgorithmException if the algorithm is not implemented by the 137 * named provider. 138 * @throws NoSuchProviderException if the named provider was not found. 139 * @throws IllegalArgumentException if either <code>algorithm</code> or 140 * <code>provider</code> is <code>null</code> or empty. 141 */ 142 public static AlgorithmParameterGenerator getInstance(String algorithm, 143 String provider) 144 throws NoSuchAlgorithmException, NoSuchProviderException 145 { 146 if (provider == null) 147 throw new IllegalArgumentException("provider MUST NOT be null"); 148 provider = provider.trim(); 149 if (provider.length() == 0) 150 throw new IllegalArgumentException("provider MUST NOT be empty"); 151 Provider p = Security.getProvider(provider); 152 if (p == null) 153 throw new NoSuchProviderException(provider); 154 return getInstance(algorithm, p); 155 } 156 157 /** 158 * Returns a new <code>AlgorithmParameterGenerator</code> instance which 159 * generates algorithm parameters for the specified algorithm. 160 * 161 * @param algorithm the name of algorithm to use. 162 * @param provider the {@link Provider} to use. 163 * @return the new instance. 164 * @throws NoSuchAlgorithmException if the algorithm is not implemented by 165 * {@link Provider}. 166 * @throws IllegalArgumentException if either <code>algorithm</code> or 167 * <code>provider</code> is <code>null</code>, or if 168 * <code>algorithm</code> is an empty string. 169 * @since 1.4 170 * @see Provider 171 */ 172 public static AlgorithmParameterGenerator getInstance(String algorithm, 173 Provider provider) 174 throws NoSuchAlgorithmException 175 { 176 CPStringBuilder sb = new CPStringBuilder() 177 .append("AlgorithmParameterGenerator for algorithm [") 178 .append(algorithm).append("] from provider[") 179 .append(provider).append("] could not be created"); 180 Throwable cause; 181 try 182 { 183 Object spi = Engine.getInstance(ALGORITHM_PARAMETER_GENERATOR, 184 algorithm, 185 provider); 186 return new AlgorithmParameterGenerator((AlgorithmParameterGeneratorSpi) spi, 187 provider, 188 algorithm); 189 } 190 catch (InvocationTargetException x) 191 { 192 cause = x.getCause(); 193 if (cause instanceof NoSuchAlgorithmException) 194 throw (NoSuchAlgorithmException) cause; 195 if (cause == null) 196 cause = x; 197 } 198 catch (ClassCastException x) 199 { 200 cause = x; 201 } 202 NoSuchAlgorithmException x = new NoSuchAlgorithmException(sb.toString()); 203 x.initCause(cause); 204 throw x; 205 } 206 207 /** @return the {@link Provider} of this generator. */ 208 public final Provider getProvider() 209 { 210 return provider; 211 } 212 213 /** 214 * Initializes this instance with the specified size. Since no source of 215 * randomness is supplied, a default one will be used. 216 * 217 * @param size 218 * size (in bits) to use. 219 */ 220 public final void init(int size) 221 { 222 init(size, new SecureRandom()); 223 } 224 225 /** 226 * Initializes this instance with the specified key-size and source of 227 * randomness. 228 * 229 * @param size 230 * the size (in bits) to use. 231 * @param random 232 * the {@link SecureRandom} to use. 233 */ 234 public final void init(int size, SecureRandom random) 235 { 236 paramGenSpi.engineInit(size, random); 237 } 238 239 /** 240 * Initializes this instance with the specified {@link AlgorithmParameterSpec}. 241 * Since no source of randomness is supplied, a default one will be used. 242 * 243 * @param genParamSpec 244 * the {@link AlgorithmParameterSpec} to use. 245 * @throws InvalidAlgorithmParameterException 246 * if <code>genParamSpec</code> is invalid. 247 */ 248 public final void init(AlgorithmParameterSpec genParamSpec) 249 throws InvalidAlgorithmParameterException 250 { 251 init(genParamSpec, new SecureRandom()); 252 } 253 254 /** 255 * Initializes this instance with the specified {@link AlgorithmParameterSpec} 256 * and source of randomness. 257 * 258 * @param genParamSpec 259 * the {@link AlgorithmParameterSpec} to use. 260 * @param random 261 * the {@link SecureRandom} to use. 262 * @throws InvalidAlgorithmParameterException 263 * if <code>genParamSpec</code> is invalid. 264 */ 265 public final void init(AlgorithmParameterSpec genParamSpec, 266 SecureRandom random) 267 throws InvalidAlgorithmParameterException 268 { 269 paramGenSpi.engineInit(genParamSpec, random); 270 } 271 272 /** @return a new instance of {@link AlgorithmParameters}. */ 273 public final AlgorithmParameters generateParameters() 274 { 275 return paramGenSpi.engineGenerateParameters(); 276 } 277 }