1   /*
    2    * Copyright (c) 1997, 2007, Oracle and/or its affiliates. All rights reserved.
    3    * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
    4    *
    5    * This code is free software; you can redistribute it and/or modify it
    6    * under the terms of the GNU General Public License version 2 only, as
    7    * published by the Free Software Foundation.  Oracle designates this
    8    * particular file as subject to the "Classpath" exception as provided
    9    * by Oracle in the LICENSE file that accompanied this code.
   10    *
   11    * This code is distributed in the hope that it will be useful, but WITHOUT
   12    * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
   13    * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
   14    * version 2 for more details (a copy is included in the LICENSE file that
   15    * accompanied this code).
   16    *
   17    * You should have received a copy of the GNU General Public License version
   18    * 2 along with this work; if not, write to the Free Software Foundation,
   19    * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
   20    *
   21    * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
   22    * or visit www.oracle.com if you need additional information or have any
   23    * questions.
   24    */
   25   
   26   package javax.crypto;
   27   
   28   import java.security;
   29   import java.security.spec;
   30   
   31   /**
   32    * This class defines the <i>Service Provider Interface</i> (<b>SPI</b>)
   33    * for the <code>SecretKeyFactory</code> class.
   34    * All the abstract methods in this class must be implemented by each
   35    * cryptographic service provider who wishes to supply the implementation
   36    * of a secret-key factory for a particular algorithm.
   37    *
   38    * <P> A provider should document all the key specifications supported by its
   39    * secret key factory.
   40    * For example, the DES secret-key factory supplied by the "SunJCE" provider
   41    * supports <code>DESKeySpec</code> as a transparent representation of DES
   42    * keys, and that provider's secret-key factory for Triple DES keys supports
   43    * <code>DESedeKeySpec</code> as a transparent representation of Triple DES
   44    * keys.
   45    *
   46    * @author Jan Luehe
   47    *
   48    * @see SecretKey
   49    * @see javax.crypto.spec.DESKeySpec
   50    * @see javax.crypto.spec.DESedeKeySpec
   51    * @since 1.4
   52    */
   53   
   54   public abstract class SecretKeyFactorySpi {
   55   
   56       /**
   57        * Generates a <code>SecretKey</code> object from the
   58        * provided key specification (key material).
   59        *
   60        * @param keySpec the specification (key material) of the secret key
   61        *
   62        * @return the secret key
   63        *
   64        * @exception InvalidKeySpecException if the given key specification
   65        * is inappropriate for this secret-key factory to produce a secret key.
   66        */
   67       protected abstract SecretKey engineGenerateSecret(KeySpec keySpec)
   68           throws InvalidKeySpecException;
   69   
   70       /**
   71        * Returns a specification (key material) of the given key
   72        * object in the requested format.
   73        *
   74        * @param key the key
   75        *
   76        * @param keySpec the requested format in which the key material shall be
   77        * returned
   78        *
   79        * @return the underlying key specification (key material) in the
   80        * requested format
   81        *
   82        * @exception InvalidKeySpecException if the requested key specification is
   83        * inappropriate for the given key (e.g., the algorithms associated with
   84        * <code>key</code> and <code>keySpec</code> do not match, or
   85        * <code>key</code> references a key on a cryptographic hardware device
   86        * whereas <code>keySpec</code> is the specification of a software-based
   87        * key), or the given key cannot be dealt with
   88        * (e.g., the given key has an algorithm or format not supported by this
   89        * secret-key factory).
   90        */
   91       protected abstract KeySpec engineGetKeySpec(SecretKey key, Class keySpec)
   92           throws InvalidKeySpecException;
   93   
   94       /**
   95        * Translates a key object, whose provider may be unknown or
   96        * potentially untrusted, into a corresponding key object of this
   97        * secret-key factory.
   98        *
   99        * @param key the key whose provider is unknown or untrusted
  100        *
  101        * @return the translated key
  102        *
  103        * @exception InvalidKeyException if the given key cannot be processed
  104        * by this secret-key factory.
  105        */
  106       protected abstract SecretKey engineTranslateKey(SecretKey key)
  107           throws InvalidKeyException;
  108   }