001 /* KeyFactory.java --- Key Factory Class 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.security.Engine; 042 043 import java.lang.reflect.InvocationTargetException; 044 import java.security.spec.InvalidKeySpecException; 045 import java.security.spec.KeySpec; 046 047 /** 048 * Key factories are used to convert keys (opaque cryptographic keys of type 049 * {@link Key}) into key specifications (transparent representations of the 050 * underlying key material). 051 * 052 * <p>Key factories are bi-directional. They allow a key class to be converted 053 * into a key specification (key material) and back again. For example DSA 054 * public keys can be specified as <code>DSAPublicKeySpec</code> or 055 * <code>X509EncodedKeySpec</code>. A key factory translates these key 056 * specifications.</p> 057 * 058 * @since 1.2 059 * @see Key 060 * @see KeySpec 061 * @see java.security.spec.DSAPublicKeySpec 062 * @see java.security.spec.X509EncodedKeySpec 063 @author Mark Benvenuto 064 */ 065 public class KeyFactory 066 { 067 /** The service name for key factories. */ 068 private static final String KEY_FACTORY = "KeyFactory"; 069 070 private KeyFactorySpi keyFacSpi; 071 private Provider provider; 072 private String algorithm; 073 074 /** 075 * Constructs a new instance of <code>KeyFactory</code> with the specified 076 * parameters. 077 * 078 * @param keyFacSpi 079 * the key factory to use. 080 * @param provider 081 * the provider to use. 082 * @param algorithm 083 * the name of the key algorithm to use. 084 */ 085 protected KeyFactory(KeyFactorySpi keyFacSpi, Provider provider, 086 String algorithm) 087 { 088 this.keyFacSpi = keyFacSpi; 089 this.provider = provider; 090 this.algorithm = algorithm; 091 } 092 093 /** 094 * Returns a new instance of <code>KeyFactory</code> representing the 095 * specified key factory. 096 * 097 * @param algorithm the name of algorithm to use. 098 * @return a new instance repesenting the desired algorithm. 099 * @throws NoSuchAlgorithmException if the algorithm is not implemented by any 100 * provider. 101 * @throws IllegalArgumentException if <code>algorithm</code> is 102 * <code>null</code> or is an empty string. 103 */ 104 public static KeyFactory getInstance(String algorithm) 105 throws NoSuchAlgorithmException 106 { 107 Provider[] p = Security.getProviders(); 108 NoSuchAlgorithmException lastException = null; 109 for (int i = 0; i < p.length; i++) 110 try 111 { 112 return getInstance(algorithm, p[i]); 113 } 114 catch (NoSuchAlgorithmException x) 115 { 116 lastException = x; 117 } 118 if (lastException != null) 119 throw lastException; 120 throw new NoSuchAlgorithmException(algorithm); 121 } 122 123 /** 124 * Returns a new instance of <code>KeyFactory</code> representing the 125 * specified key factory from the specified provider. 126 * 127 * @param algorithm the name of algorithm to use. 128 * @param provider the name of the provider to use. 129 * @return a new instance repesenting the desired algorithm. 130 * @throws NoSuchAlgorithmException if the algorithm is not implemented by the 131 * named provider. 132 * @throws NoSuchProviderException if the named provider was not found. 133 * @throws IllegalArgumentException if either <code>algorithm</code> or 134 * <code>provider</code> is <code>null</code> or empty. 135 */ 136 public static KeyFactory getInstance(String algorithm, String provider) 137 throws NoSuchAlgorithmException, NoSuchProviderException 138 { 139 if (provider == null) 140 throw new IllegalArgumentException("provider MUST NOT be null"); 141 provider = provider.trim(); 142 if (provider.length() == 0) 143 throw new IllegalArgumentException("provider MUST NOT be empty"); 144 Provider p = Security.getProvider(provider); 145 if (p == null) 146 throw new NoSuchProviderException(provider); 147 return getInstance(algorithm, p); 148 } 149 150 /** 151 * Returns a new instance of <code>KeyFactory</code> representing the 152 * specified key factory from the designated {@link Provider}. 153 * 154 * @param algorithm the name of algorithm to use. 155 * @param provider the {@link Provider} to use. 156 * @return a new instance repesenting the desired algorithm. 157 * @throws NoSuchAlgorithmException if the algorithm is not implemented by 158 * {@link Provider}. 159 * @throws IllegalArgumentException if either <code>algorithm</code> or 160 * <code>provider</code> is <code>null</code>, or if 161 * <code>algorithm</code> is an empty string. 162 * @since 1.4 163 * @see Provider 164 */ 165 public static KeyFactory getInstance(String algorithm, Provider provider) 166 throws NoSuchAlgorithmException 167 { 168 StringBuilder sb = new StringBuilder("KeyFactory for algorithm [") 169 .append(algorithm).append("] from provider[") 170 .append(provider).append("] could not be created"); 171 Throwable cause; 172 try 173 { 174 Object spi = Engine.getInstance(KEY_FACTORY, algorithm, provider); 175 return new KeyFactory((KeyFactorySpi) spi, provider, algorithm); 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 * Returns the {@link Provider} of this instance. 196 * 197 * @return the {@link Provider} of this instance. 198 */ 199 public final Provider getProvider() 200 { 201 return provider; 202 } 203 204 /** 205 * Returns the name of the algorithm used. 206 * 207 * @return the name of the algorithm used. 208 */ 209 public final String getAlgorithm() 210 { 211 return algorithm; 212 } 213 214 /** 215 * Generates a public key from the provided key specification. 216 * 217 * @param keySpec 218 * the key specification. 219 * @return the public key. 220 * @throws InvalidKeySpecException 221 * if the key specification is invalid. 222 */ 223 public final PublicKey generatePublic(KeySpec keySpec) 224 throws InvalidKeySpecException 225 { 226 return keyFacSpi.engineGeneratePublic(keySpec); 227 } 228 229 /** 230 * Generates a private key from the provided key specification. 231 * 232 * @param keySpec 233 * the key specification. 234 * @return the private key. 235 * @throws InvalidKeySpecException 236 * if the key specification is invalid. 237 */ 238 public final PrivateKey generatePrivate(KeySpec keySpec) 239 throws InvalidKeySpecException 240 { 241 return keyFacSpi.engineGeneratePrivate(keySpec); 242 } 243 244 /** 245 * Returns a key specification for the given key. <code>keySpec</code> 246 * identifies the specification class to return the key material in. 247 * 248 * @param key 249 * the key to use. 250 * @param keySpec 251 * the specification class to use. 252 * @return the key specification in an instance of the requested specification 253 * class. 254 * @throws InvalidKeySpecException 255 * the requested key specification is inappropriate for this key or 256 * the key is unrecognized. 257 */ 258 public final <T extends KeySpec> T getKeySpec(Key key, Class<T> keySpec) 259 throws InvalidKeySpecException 260 { 261 return keyFacSpi.engineGetKeySpec(key, keySpec); 262 } 263 264 /** 265 * Translates the key from an unknown or untrusted provider into a key from 266 * this key factory. 267 * 268 * @param key 269 * the key to translate from. 270 * @return the translated key. 271 * @throws InvalidKeyException 272 * if the key cannot be processed by this key factory. 273 */ 274 public final Key translateKey(Key key) throws InvalidKeyException 275 { 276 return keyFacSpi.engineTranslateKey(key); 277 } 278 }