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      1 /*
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      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
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     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.spec;
     27 
     28 import java.security.InvalidKeyException;
     29 
     30 /**
     31  * This class specifies a DES-EDE ("triple-DES") key.
     32  *
     33  * @author Jan Luehe
     34  *
     35  * @since 1.4
     36  */
     37 public class DESedeKeySpec implements java.security.spec.KeySpec {
     38 
     39     /**
     40      * The constant which defines the length of a DESede key in bytes.
     41      */
     42     public static final int DES_EDE_KEY_LEN = 24;
     43 
     44     private byte[] key;
     45 
     46     /**
     47      * Creates a DESedeKeySpec object using the first 24 bytes in
     48      * <code>key</code> as the key material for the DES-EDE key.
     49      *
     50      * <p> The bytes that constitute the DES-EDE key are those between
     51      * <code>key[0]</code> and <code>key[23]</code> inclusive
     52      *
     53      * @param key the buffer with the DES-EDE key material. The first
     54      * 24 bytes of the buffer are copied to protect against subsequent
     55      * modification.
     56      *
     57      * @exception NullPointerException if <code>key</code> is null.
     58      * @exception InvalidKeyException if the given key material is shorter
     59      * than 24 bytes.
     60      */
     61     public DESedeKeySpec(byte[] key) throws InvalidKeyException {
     62         this(key, 0);
     63     }
     64 
     65     /**
     66      * Creates a DESedeKeySpec object using the first 24 bytes in
     67      * <code>key</code>, beginning at <code>offset</code> inclusive,
     68      * as the key material for the DES-EDE key.
     69      *
     70      * <p> The bytes that constitute the DES-EDE key are those between
     71      * <code>key[offset]</code> and <code>key[offset+23]</code> inclusive.
     72      *
     73      * @param key the buffer with the DES-EDE key material. The first
     74      * 24 bytes of the buffer beginning at <code>offset</code> inclusive
     75      * are copied to protect against subsequent modification.
     76      * @param offset the offset in <code>key</code>, where the DES-EDE key
     77      * material starts.
     78      *
     79      * @exception NullPointerException if <code>key</code> is null.
     80      * @exception InvalidKeyException if the given key material, starting at
     81      * <code>offset</code> inclusive, is shorter than 24 bytes
     82      */
     83     public DESedeKeySpec(byte[] key, int offset) throws InvalidKeyException {
     84         if (key.length - offset < 24) {
     85             throw new InvalidKeyException("Wrong key size");
     86         }
     87         this.key = new byte[24];
     88         System.arraycopy(key, offset, this.key, 0, 24);
     89     }
     90 
     91     /**
     92      * Returns the DES-EDE key.
     93      *
     94      * @return the DES-EDE key. Returns a new array
     95      * each time this method is called.
     96      */
     97     public byte[] getKey() {
     98         return this.key.clone();
     99     }
    100 
    101     /**
    102      * Checks if the given DES-EDE key, starting at <code>offset</code>
    103      * inclusive, is parity-adjusted.
    104      *
    105      * @param key    a byte array which holds the key value
    106      * @param offset the offset into the byte array
    107      * @return true if the given DES-EDE key is parity-adjusted, false
    108      * otherwise
    109      *
    110      * @exception NullPointerException if <code>key</code> is null.
    111      * @exception InvalidKeyException if the given key material, starting at
    112      * <code>offset</code> inclusive, is shorter than 24 bytes
    113      */
    114     public static boolean isParityAdjusted(byte[] key, int offset)
    115         throws InvalidKeyException {
    116             if (key.length - offset < 24) {
    117                 throw new InvalidKeyException("Wrong key size");
    118             }
    119             if (DESKeySpec.isParityAdjusted(key, offset) == false
    120                 || DESKeySpec.isParityAdjusted(key, offset + 8) == false
    121                 || DESKeySpec.isParityAdjusted(key, offset + 16) == false) {
    122                 return false;
    123             }
    124             return true;
    125     }
    126 }
    127