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      1 /*
      2  * Copyright (c) 1997, 2013, 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 /**
     29  * A secret (symmetric) key.
     30  * The purpose of this interface is to group (and provide type safety
     31  * for) all secret key interfaces.
     32  * <p>
     33  * Provider implementations of this interface must overwrite the
     34  * {@code equals} and {@code hashCode} methods inherited from
     35  * {@link java.lang.Object}, so that secret keys are compared based on
     36  * their underlying key material and not based on reference.
     37  * Implementations should override the default {@code destroy} and
     38  * {@code isDestroyed} methods from the
     39  * {@link javax.security.auth.Destroyable} interface to enable
     40  * sensitive key information to be destroyed, cleared, or in the case
     41  * where such information is immutable, unreferenced.
     42  * Finally, since {@code SecretKey} is {@code Serializable}, implementations
     43  * should also override
     44  * {@link java.io.ObjectOutputStream#writeObject(java.lang.Object)}
     45  * to prevent keys that have been destroyed from being serialized.
     46  *
     47  * <p>Keys that implement this interface return the string {@code RAW}
     48  * as their encoding format (see {@code getFormat}), and return the
     49  * raw key bytes as the result of a {@code getEncoded} method call. (The
     50  * {@code getFormat} and {@code getEncoded} methods are inherited
     51  * from the {@link java.security.Key} parent interface.)
     52  *
     53  * @author Jan Luehe
     54  *
     55  * @see SecretKeyFactory
     56  * @see Cipher
     57  * @since 1.4
     58  */
     59 
     60 public interface SecretKey extends
     61     java.security.Key, javax.security.auth.Destroyable {
     62 
     63     /**
     64      * The class fingerprint that is set to indicate serialization
     65      * compatibility since J2SE 1.4.
     66      */
     67     static final long serialVersionUID = -4795878709595146952L;
     68 }
     69