001/* SecretKeyFactory.java -- Factory for creating secret keys. 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.InvalidKeyException; 045import java.security.NoSuchAlgorithmException; 046import java.security.NoSuchProviderException; 047import java.security.Provider; 048import java.security.Security; 049import java.security.spec.InvalidKeySpecException; 050import java.security.spec.KeySpec; 051 052/** 053 * A secret key factory translates {@link SecretKey} objects to and from 054 * {@link java.security.spec.KeySpec} objects, and can translate between 055 * different vendors' representations of {@link SecretKey} objects (for 056 * security or semantics; whichever applies). 057 * 058 * @author Casey Marshall (csm@gnu.org) 059 * @since 1.4 060 * @see SecretKey 061 */ 062public class SecretKeyFactory 063{ 064 065 // Constants and fields. 066 // ------------------------------------------------------------------------ 067 068 private static final String SERVICE = "SecretKeyFactory"; 069 070 /** The underlying factory implementation. */ 071 private SecretKeyFactorySpi skfSpi; 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 secret key factory. 084 * 085 * @param skfSpi The underlying factory implementation. 086 * @param provider The provider. 087 * @param algorithm The algorithm name. 088 */ 089 protected SecretKeyFactory(SecretKeyFactorySpi skfSpi, Provider provider, 090 String algorithm) 091 { 092 this.skfSpi = skfSpi; 093 this.provider = provider; 094 this.algorithm = algorithm; 095 } 096 097 /** 098 * Create a new secret key factory from the first appropriate instance. 099 * 100 * @param algorithm The algorithm name. 101 * @return The appropriate key factory, if found. 102 * @throws NoSuchAlgorithmException If no provider implements the specified 103 * algorithm. 104 * @throws IllegalArgumentException if <code>algorithm</code> is 105 * <code>null</code> or is an empty string. 106 */ 107 public static final SecretKeyFactory getInstance(String algorithm) 108 throws NoSuchAlgorithmException 109 { 110 Provider[] p = Security.getProviders(); 111 NoSuchAlgorithmException lastException = null; 112 for (int i = 0; i < p.length; i++) 113 try 114 { 115 return getInstance(algorithm, p[i]); 116 } 117 catch (NoSuchAlgorithmException x) 118 { 119 lastException = x; 120 } 121 if (lastException != null) 122 throw lastException; 123 throw new NoSuchAlgorithmException(algorithm); 124 } 125 126 /** 127 * Create a new secret key factory from the named provider. 128 * 129 * @param algorithm The algorithm name. 130 * @param provider The provider name. 131 * @return The appropriate key factory, if found. 132 * @throws NoSuchAlgorithmException If the named provider does not implement 133 * the algorithm. 134 * @throws NoSuchProviderException If the named provider does not exist. 135 * @throws IllegalArgumentException if either <code>algorithm</code> or 136 * <code>provider</code> is <code>null</code>, or if 137 * <code>algorithm</code> is an empty string. 138 */ 139 public static final SecretKeyFactory getInstance(String algorithm, 140 String provider) 141 throws NoSuchAlgorithmException, NoSuchProviderException 142 { 143 if (provider == null) 144 throw new IllegalArgumentException("provider MUST NOT be null"); 145 Provider p = Security.getProvider(provider); 146 if (p == null) 147 throw new NoSuchProviderException(provider); 148 return getInstance(algorithm, p); 149 } 150 151 /** 152 * Create a new secret key factory from the specified provider. 153 * 154 * @param algorithm The algorithm name. 155 * @param provider The provider. 156 * @return The appropriate key factory, if found. 157 * @throws NoSuchAlgorithmException If the provider does not implement the 158 * algorithm. 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 */ 163 public static final SecretKeyFactory getInstance(String algorithm, 164 Provider provider) 165 throws NoSuchAlgorithmException 166 { 167 StringBuilder sb = new StringBuilder("SecretKeyFactory algorithm [") 168 .append(algorithm).append("] from provider[") 169 .append(provider).append("] could not be created"); 170 Throwable cause; 171 try 172 { 173 Object spi = Engine.getInstance(SERVICE, algorithm, provider); 174 return new SecretKeyFactory((SecretKeyFactorySpi) spi, provider, algorithm); 175 } 176 catch (InvocationTargetException x) 177 { 178 cause = x.getCause(); 179 if (cause instanceof NoSuchAlgorithmException) 180 throw (NoSuchAlgorithmException) cause; 181 if (cause == null) 182 cause = x; 183 } 184 catch (ClassCastException x) 185 { 186 cause = x; 187 } 188 NoSuchAlgorithmException x = new NoSuchAlgorithmException(sb.toString()); 189 x.initCause(cause); 190 throw x; 191 } 192 193 /** 194 * Generate a secret key from a key specification, if possible. 195 * 196 * @param keySpec The key specification. 197 * @return The secret key. 198 * @throws java.security.InvalidKeySpecException If the key specification 199 * cannot be transformed into a secret key. 200 */ 201 public final SecretKey generateSecret(KeySpec keySpec) 202 throws InvalidKeySpecException 203 { 204 return skfSpi.engineGenerateSecret(keySpec); 205 } 206 207 /** 208 * Get the algorithm name. 209 * 210 * @return The algorithm name. 211 */ 212 public final String getAlgorithm() 213 { 214 return algorithm; 215 } 216 217 /** 218 * Get the key specification from a secret key. 219 * 220 * @param key The secret key. 221 * @param keySpec The target key specification class. 222 * @return The key specification. 223 * @throws java.security.spec.InvalidKeySpecException If the secret key cannot 224 * be transformed into the specified key specification. 225 */ 226 public final KeySpec getKeySpec(SecretKey key, Class keySpec) 227 throws InvalidKeySpecException 228 { 229 return skfSpi.engineGetKeySpec(key, keySpec); 230 } 231 232 /** 233 * Get the provider of this implementation. 234 * 235 * @return The provider. 236 */ 237 public final Provider getProvider() 238 { 239 return provider; 240 } 241 242 /** 243 * Translate a secret key into another form. 244 * 245 * @param key The key to translate. 246 * @return The translated key. 247 * @throws java.security.InvalidKeyException If the argument cannot be 248 * translated. 249 */ 250 public final SecretKey translateKey(SecretKey key) 251 throws InvalidKeyException 252 { 253 return skfSpi.engineTranslateKey(key); 254 } 255}