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From-SVN: r102074

1 files changed, 151 insertions, 0 deletions

diff --git a/libjava/classpath/javax/crypto/spec/DESedeKeySpec.java b/libjava/classpath/javax/crypto/spec/DESedeKeySpec.java
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+/* DESedeKeySpec.java -- Keys for triple-DES.
+   Copyright (C) 2004  Free Software Foundation, Inc.
+
+This file is part of GNU Classpath.
+
+GNU Classpath is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2, or (at your option)
+any later version.
+
+GNU Classpath is distributed in the hope that it will be useful, but
+WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with GNU Classpath; see the file COPYING.  If not, write to the
+Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+02110-1301 USA.
+
+Linking this library statically or dynamically with other modules is
+making a combined work based on this library.  Thus, the terms and
+conditions of the GNU General Public License cover the whole
+combination.
+
+As a special exception, the copyright holders of this library give you
+permission to link this library with independent modules to produce an
+executable, regardless of the license terms of these independent
+modules, and to copy and distribute the resulting executable under
+terms of your choice, provided that you also meet, for each linked
+independent module, the terms and conditions of the license of that
+module.  An independent module is a module which is not derived from
+or based on this library.  If you modify this library, you may extend
+this exception to your version of the library, but you are not
+obligated to do so.  If you do not wish to do so, delete this
+exception statement from your version. */
+
+
+package javax.crypto.spec;
+
+import java.security.InvalidKeyException;
+import java.security.spec.KeySpec;
+
+/**
+ * This class is a transparent wrapper for DES-EDE (Triple-DES) keys,
+ * which are arrays of 24 bytes.
+ *
+ * @author Casey Marshall (csm@gnu.org)
+ * @since 1.4
+ */
+public class DESedeKeySpec implements KeySpec
+{
+
+  // Constants.
+  // ------------------------------------------------------------------------
+
+  /**
+   * The length of a triple-DES key, in bytes.
+   */
+  public static final int DES_EDE_KEY_LEN = 24;
+
+  /**
+   * The key bytes.
+   */
+  private byte[] key;
+
+  // Constructors.
+  // ------------------------------------------------------------------------
+
+  /**
+   * Create a new DES-EDE key spec, copying the first 24 bytes from the
+   * byte array.
+   *
+   * @param key The key bytes.
+   * @throws java.security.InvalidKeyException If there are less than 24
+   *         bytes in the array.
+   */
+  public DESedeKeySpec(byte[] key) throws InvalidKeyException
+  {
+    this(key, 0);
+  }
+
+  /**
+   * Create a new DES-EDE key spec, starting at <code>offset</code> in
+   * the byte array. The first 24 bytes starting at <code>offset</code>
+   * are copied.
+   *
+   * @param key    The key bytes.
+   * @param offset The offset into the byte array at which to begin.
+   * @throws java.security.InvalidKeyException If there are less than 24
+   *         bytes starting at <code>offset</code>.
+   */
+  public DESedeKeySpec(byte[] key, int offset) throws InvalidKeyException
+  {
+    if (key.length - offset < DES_EDE_KEY_LEN)
+      {
+        throw new InvalidKeyException("DES-EDE keys must be 24 bytes long");
+      }
+    this.key = new byte[DES_EDE_KEY_LEN];
+    System.arraycopy(key, offset, this.key, 0, DES_EDE_KEY_LEN);
+  }
+
+  // Class methods.
+  // ------------------------------------------------------------------------
+
+  /**
+   * Returns whether or not the given key is <i>parity adjusted</i>;
+   * i.e. every byte in the key has an odd number of "1" bits.
+   *
+   * @param key    The key bytes, considered between <code>[offset,
+   *               offset+23]</code>
+   * @param offset The offset into the byte array at which to begin.
+   * @return True if all bytes have an odd number of "1" bits.
+   * @throws java.security.InvalidKeyException If there are not enough
+   *         bytes in the array.
+   */
+  public static boolean isParityAdjusted(byte[] key, int offset)
+    throws InvalidKeyException
+  {
+    if (key.length - offset < DES_EDE_KEY_LEN)
+      {
+        throw new InvalidKeyException("DES-EDE keys must be 24 bytes long");
+      }
+    boolean parity = false;
+    boolean oddbits = false;
+    for (int i = 0; i < DES_EDE_KEY_LEN; i++)
+      {
+        oddbits = false;
+        for (int j = 0; j < 8; j++)
+          {
+            oddbits ^= (key[i+offset] & 1 << j) != 0;
+          }
+        parity &= oddbits;
+      }
+    return parity;
+  }
+
+  // Instance methods.
+  // ------------------------------------------------------------------------
+
+  /**
+   * Return the key as a byte array. This method does not copy the byte
+   * array.
+   *
+   * @return The key bytes.
+   */
+  public byte[] getKey()
+  {
+    return key;
+  }
+}