1 files changed, 159 insertions, 0 deletions
diff --git a/libjava/classpath/gnu/javax/crypto/DiffieHellmanImpl.java b/libjava/classpath/gnu/javax/crypto/DiffieHellmanImpl.java
new file mode 100644
index 00000000000..4797af7cf79
--- /dev/null
+++ b/libjava/classpath/gnu/javax/crypto/DiffieHellmanImpl.java
@@ -0,0 +1,159 @@
+/* DiffieHellmanImpl.java -- implementation of the Diffie-Hellman key agreement.
+   Copyright (C) 2005  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 gnu.javax.crypto;
+
+import gnu.java.security.provider.GnuDHPublicKey;
+
+import java.math.BigInteger;
+
+import java.security.Key;
+import java.security.InvalidKeyException;
+import java.security.PrivateKey;
+import java.security.PublicKey;
+import java.security.SecureRandom;
+import java.security.spec.AlgorithmParameterSpec;
+
+import javax.crypto.KeyAgreementSpi;
+import javax.crypto.SecretKey;
+import javax.crypto.interfaces.DHPrivateKey;
+import javax.crypto.interfaces.DHPublicKey;
+import javax.crypto.spec.DHParameterSpec;
+import javax.crypto.spec.SecretKeySpec;
+
+/**
+ * The Diffie-Hellman key agreement.
+ *
+ * @author Casey Marshall (csm@gnu.org)
+ */
+public final class DiffieHellmanImpl extends KeyAgreementSpi
+{
+
+  /** The private key being used for this agreement. */
+  private DHPrivateKey key;
+
+  /** The current result. */
+  private BigInteger result;
+
+  /** True if the caller told us we are done. */
+  private boolean last_phase_done;
+
+  /** Trivial default constructor. */
+  public DiffieHellmanImpl ()
+  {
+    key = null;
+    result = null;
+    last_phase_done = false;
+  }
+
+  // KeyAgreementSpi methods.
+
+  protected Key engineDoPhase (final Key incoming, final boolean lastPhase)
+    throws InvalidKeyException
+  {
+    if (key == null)
+      throw new IllegalStateException ("not initialized");
+    if (last_phase_done)
+      throw new IllegalStateException ("last phase already done");
+
+    if (!(incoming instanceof DHPublicKey))
+      throw new InvalidKeyException ("expecting javax.crypto.interfaces.DHPublicKey");
+    DHPublicKey pub = (DHPublicKey) incoming;
+    DHParameterSpec s1 = key.getParams();
+    DHParameterSpec s2 = pub.getParams();
+    if (!s1.getG().equals (s2.getG())
+        || !s1.getP().equals (s2.getP())
+        || s1.getL() != s2.getL())
+      throw new InvalidKeyException ("supplied key is not compatible");
+
+    result = pub.getY().modPow (key.getX(), s1.getP());
+    if (lastPhase)
+      {
+	last_phase_done = true;
+	return null;
+      }
+
+    throw new IllegalArgumentException ("only supports two-party Diffie Hellman");
+  }
+
+  protected byte[] engineGenerateSecret ()
+  {
+    if (result == null || !last_phase_done)
+      throw new IllegalStateException ("not finished");
+
+    byte[] buf = result.toByteArray ();
+    if (buf[0] == 0x00)
+      {
+	byte[] buf2 = new byte[buf.length - 1];
+	System.arraycopy (buf, 1, buf2, 0, buf2.length);
+	buf = buf2;
+      }
+    return buf;
+  }
+
+  protected int engineGenerateSecret (final byte[] secret, final int offset)
+  {
+    byte[] s = engineGenerateSecret();
+    System.arraycopy (s, 0, secret, offset, s.length);
+    return s.length;
+  }
+
+  protected SecretKey engineGenerateSecret (final String algorithm)
+    throws InvalidKeyException
+  {
+    byte[] s = engineGenerateSecret();
+    return new SecretKeySpec (s, algorithm);
+  }
+
+  protected void engineInit (final Key key, final SecureRandom random)
+    throws InvalidKeyException
+  {
+    if (!(key instanceof DHPrivateKey))
+      throw new InvalidKeyException ("not a javax.crypto.interfaces.DHPrivateKey");
+    this.key = (DHPrivateKey) key;
+    result = null;
+    last_phase_done = false;
+  }
+
+  protected void engineInit (final Key key, final AlgorithmParameterSpec params,
+                             final SecureRandom random)
+    throws InvalidKeyException
+  {
+    engineInit (key, random);
+  }
+}