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.lang.CPStringBuilder; 042 043 import gnu.java.security.Engine; 044 045 import java.lang.reflect.InvocationTargetException; 046 import java.security.spec.InvalidKeySpecException; 047 import java.security.spec.KeySpec; 048 049 /** 050 * Key factories are used to convert keys (opaque cryptographic keys of type 051 * {@link Key}) into key specifications (transparent representations of the 052 * underlying key material). 053 * 054 * <p>Key factories are bi-directional. They allow a key class to be converted 055 * into a key specification (key material) and back again. For example DSA 056 * public keys can be specified as <code>DSAPublicKeySpec</code> or 057 * <code>X509EncodedKeySpec</code>. A key factory translates these key 058 * specifications.</p> 059 * 060 * @since 1.2 061 * @see Key 062 * @see KeySpec 063 * @see java.security.spec.DSAPublicKeySpec 064 * @see java.security.spec.X509EncodedKeySpec 065 @author Mark Benvenuto 066 */ 067 public class KeyFactory 068 { 069 /** The service name for key factories. */ 070 private static final String KEY_FACTORY = "KeyFactory"; 071 072 private KeyFactorySpi keyFacSpi; 073 private Provider provider; 074 private String algorithm; 075 076 /** 077 * Constructs a new instance of <code>KeyFactory</code> with the specified 078 * parameters. 079 * 080 * @param keyFacSpi 081 * the key factory to use. 082 * @param provider 083 * the provider to use. 084 * @param algorithm 085 * the name of the key algorithm to use. 086 */ 087 protected KeyFactory(KeyFactorySpi keyFacSpi, Provider provider, 088 String algorithm) 089 { 090 this.keyFacSpi = keyFacSpi; 091 this.provider = provider; 092 this.algorithm = algorithm; 093 } 094 095 /** 096 * Returns a new instance of <code>KeyFactory</code> representing the 097 * specified key factory. 098 * 099 * @param algorithm the name of algorithm to use. 100 * @return a new instance repesenting the desired algorithm. 101 * @throws NoSuchAlgorithmException if the algorithm is not implemented by any 102 * provider. 103 * @throws IllegalArgumentException if <code>algorithm</code> is 104 * <code>null</code> or is an empty string. 105 */ 106 public static KeyFactory getInstance(String algorithm) 107 throws NoSuchAlgorithmException 108 { 109 Provider[] p = Security.getProviders(); 110 NoSuchAlgorithmException lastException = null; 111 for (int i = 0; i < p.length; i++) 112 try 113 { 114 return getInstance(algorithm, p[i]); 115 } 116 catch (NoSuchAlgorithmException x) 117 { 118 lastException = x; 119 } 120 if (lastException != null) 121 throw lastException; 122 throw new NoSuchAlgorithmException(algorithm); 123 } 124 125 /** 126 * Returns a new instance of <code>KeyFactory</code> representing the 127 * specified key factory from the specified provider. 128 * 129 * @param algorithm the name of algorithm to use. 130 * @param provider the name of the provider to use. 131 * @return a new instance repesenting the desired algorithm. 132 * @throws NoSuchAlgorithmException if the algorithm is not implemented by the 133 * named provider. 134 * @throws NoSuchProviderException if the named provider was not found. 135 * @throws IllegalArgumentException if either <code>algorithm</code> or 136 * <code>provider</code> is <code>null</code> or empty. 137 */ 138 public static KeyFactory getInstance(String algorithm, String provider) 139 throws NoSuchAlgorithmException, NoSuchProviderException 140 { 141 if (provider == null) 142 throw new IllegalArgumentException("provider MUST NOT be null"); 143 provider = provider.trim(); 144 if (provider.length() == 0) 145 throw new IllegalArgumentException("provider MUST NOT be empty"); 146 Provider p = Security.getProvider(provider); 147 if (p == null) 148 throw new NoSuchProviderException(provider); 149 return getInstance(algorithm, p); 150 } 151 152 /** 153 * Returns a new instance of <code>KeyFactory</code> representing the 154 * specified key factory from the designated {@link Provider}. 155 * 156 * @param algorithm the name of algorithm to use. 157 * @param provider the {@link Provider} to use. 158 * @return a new instance repesenting the desired algorithm. 159 * @throws NoSuchAlgorithmException if the algorithm is not implemented by 160 * {@link Provider}. 161 * @throws IllegalArgumentException if either <code>algorithm</code> or 162 * <code>provider</code> is <code>null</code>, or if 163 * <code>algorithm</code> is an empty string. 164 * @since 1.4 165 * @see Provider 166 */ 167 public static KeyFactory getInstance(String algorithm, Provider provider) 168 throws NoSuchAlgorithmException 169 { 170 CPStringBuilder sb = new CPStringBuilder("KeyFactory for algorithm [") 171 .append(algorithm).append("] from provider[") 172 .append(provider).append("] could not be created"); 173 Throwable cause; 174 try 175 { 176 Object spi = Engine.getInstance(KEY_FACTORY, algorithm, provider); 177 return new KeyFactory((KeyFactorySpi) spi, provider, algorithm); 178 } 179 catch (InvocationTargetException x) 180 { 181 cause = x.getCause(); 182 if (cause instanceof NoSuchAlgorithmException) 183 throw (NoSuchAlgorithmException) cause; 184 if (cause == null) 185 cause = x; 186 } 187 catch (ClassCastException x) 188 { 189 cause = x; 190 } 191 NoSuchAlgorithmException x = new NoSuchAlgorithmException(sb.toString()); 192 x.initCause(cause); 193 throw x; 194 } 195 196 /** 197 * Returns the {@link Provider} of this instance. 198 * 199 * @return the {@link Provider} of this instance. 200 */ 201 public final Provider getProvider() 202 { 203 return provider; 204 } 205 206 /** 207 * Returns the name of the algorithm used. 208 * 209 * @return the name of the algorithm used. 210 */ 211 public final String getAlgorithm() 212 { 213 return algorithm; 214 } 215 216 /** 217 * Generates a public key from the provided key specification. 218 * 219 * @param keySpec 220 * the key specification. 221 * @return the public key. 222 * @throws InvalidKeySpecException 223 * if the key specification is invalid. 224 */ 225 public final PublicKey generatePublic(KeySpec keySpec) 226 throws InvalidKeySpecException 227 { 228 return keyFacSpi.engineGeneratePublic(keySpec); 229 } 230 231 /** 232 * Generates a private key from the provided key specification. 233 * 234 * @param keySpec 235 * the key specification. 236 * @return the private key. 237 * @throws InvalidKeySpecException 238 * if the key specification is invalid. 239 */ 240 public final PrivateKey generatePrivate(KeySpec keySpec) 241 throws InvalidKeySpecException 242 { 243 return keyFacSpi.engineGeneratePrivate(keySpec); 244 } 245 246 /** 247 * Returns a key specification for the given key. <code>keySpec</code> 248 * identifies the specification class to return the key material in. 249 * 250 * @param key 251 * the key to use. 252 * @param keySpec 253 * the specification class to use. 254 * @return the key specification in an instance of the requested specification 255 * class. 256 * @throws InvalidKeySpecException 257 * the requested key specification is inappropriate for this key or 258 * the key is unrecognized. 259 */ 260 public final <T extends KeySpec> T getKeySpec(Key key, Class<T> keySpec) 261 throws InvalidKeySpecException 262 { 263 return keyFacSpi.engineGetKeySpec(key, keySpec); 264 } 265 266 /** 267 * Translates the key from an unknown or untrusted provider into a key from 268 * this key factory. 269 * 270 * @param key 271 * the key to translate from. 272 * @return the translated key. 273 * @throws InvalidKeyException 274 * if the key cannot be processed by this key factory. 275 */ 276 public final Key translateKey(Key key) throws InvalidKeyException 277 { 278 return keyFacSpi.engineTranslateKey(key); 279 } 280 }