001    /* KeyFactorySpi.java --- Key Factory Service Provider Interface
002       Copyright (C) 1999, 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 java.security.spec.InvalidKeySpecException;
042    import java.security.spec.KeySpec;
043    
044    /**
045     * KeyFactorySpi is the Service Provider Interface (SPI) for the
046     * KeyFactory class. This is the interface for providers to
047     * supply to implement a key factory for an algorithm.
048     *
049     * Key factories are used to convert keys (opaque cryptographic
050     * keys of type Key) into key specifications (transparent
051     * representations of the underlying key material).
052     *
053     * Key factories are bi-directional. They allow a key class
054     * to be converted into a key specification (key material) and
055     * back again.
056     *
057     * For example DSA public keys can be specified as
058     * DSAPublicKeySpec or X509EncodedKeySpec. The key factory
059     * translate these key specifications.
060     *
061     * @since JDK 1.2
062     * @author Mark Benvenuto
063     */
064    public abstract class KeyFactorySpi
065    {
066      /**
067       * Constucts a new KeyFactorySpi.
068       */
069      public KeyFactorySpi()
070      {
071      }
072    
073      /**
074       * Generates a public key from the provided key specification.
075       *
076       * @param keySpec key specification
077       *
078       * @return the public key
079       *
080       * @throws InvalidKeySpecException invalid key specification for
081       * this key factory to produce a public key
082       */
083      protected abstract PublicKey engineGeneratePublic(KeySpec keySpec)
084        throws InvalidKeySpecException;
085    
086    
087      /**
088       * Generates a private key from the provided key specification.
089       *
090       * @param keySpec key specification
091       *
092       * @return the private key
093       *
094       * @throws InvalidKeySpecException invalid key specification for
095       * this key factory to produce a private key
096       */
097      protected abstract PrivateKey engineGeneratePrivate(KeySpec keySpec)
098        throws InvalidKeySpecException;
099    
100      /**
101       * Returns a key specification for the given key. keySpec
102       * identifies the specification class to return the key
103       * material in.
104       *
105       * @param key the key
106       * @param keySpec the specification class to return the
107       * key material in.
108       *
109       * @return the key specification in an instance of the requested
110       * specification class
111       *
112       * @throws InvalidKeySpecException the requested key specification
113       * is inappropriate for this key or the key is
114       * unrecognized.
115       */
116      protected abstract <T extends KeySpec> T engineGetKeySpec(Key key,
117                                                                Class<T> keySpec)
118        throws InvalidKeySpecException;
119    
120    
121      /**
122       * Translates the key from an unknown or untrusted provider
123       * into a key for this key factory.
124       *
125       * @param key key from an unknown or untrusted provider
126       *
127       * @return the translated key
128       *
129       * @throws InvalidKeyException if the key cannot be
130       * processed by this key factory
131       */
132      protected abstract Key engineTranslateKey(Key key)
133        throws InvalidKeyException;
134    }