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diff --git a/gnu/javax/crypto/key/dh/ElGamalReceiver.java b/gnu/javax/crypto/key/dh/ElGamalReceiver.java
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+/* ElGamalReceiver.java -- 
+   Copyright (C) 2003, 2006 Free Software Foundation, Inc.
+
+This file is a 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 of the License, 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; if not, write to the Free Software
+Foundation, Inc., 51 Franklin St, 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.key.dh;
+
+import gnu.javax.crypto.key.KeyAgreementException;
+import gnu.javax.crypto.key.IncomingMessage;
+import gnu.javax.crypto.key.OutgoingMessage;
+
+import java.math.BigInteger;
+import java.security.SecureRandom;
+import java.util.Map;
+
+import javax.crypto.interfaces.DHPrivateKey;
+
+/**
+ * <p>This implementation is the receiver's part of the ElGamal key agreement
+ * exchange (B in [HAC]).</p>
+ *
+ * @see ElGamalKeyAgreement
+ */
+public class ElGamalReceiver extends ElGamalKeyAgreement
+{
+
+  // Constants and variables
+  // -------------------------------------------------------------------------
+
+  /** The recipient's private key. */
+  private DHPrivateKey B;
+
+  // Constructor(s)
+  // -------------------------------------------------------------------------
+
+  // default 0-arguments constructor
+
+  // Class methods
+  // -------------------------------------------------------------------------
+
+  // Instance methods
+  // -------------------------------------------------------------------------
+
+  // implementation of abstract methods in base class ------------------------
+
+  protected void engineInit(Map attributes) throws KeyAgreementException
+  {
+    rnd = (SecureRandom) attributes.get(SOURCE_OF_RANDOMNESS);
+    // One-time setup (key generation and publication). Each user B generates
+    // a keypair and publishes its public key
+    B = (DHPrivateKey) attributes.get(KA_ELGAMAL_RECIPIENT_PRIVATE_KEY);
+    if (B == null)
+      {
+        throw new KeyAgreementException("missing recipient private key");
+      }
+  }
+
+  protected OutgoingMessage engineProcessMessage(IncomingMessage in)
+      throws KeyAgreementException
+  {
+    switch (step)
+      {
+      case 0:
+        return computeSharedSecret(in);
+      default:
+        throw new IllegalStateException("unexpected state");
+      }
+  }
+
+  // own methods -------------------------------------------------------------
+
+  private OutgoingMessage computeSharedSecret(IncomingMessage in)
+      throws KeyAgreementException
+  {
+    // (b) B computes the same key on receipt of message (1) as
+    // K = (g^x)^xb mod p
+    BigInteger m1 = in.readMPI();
+    if (m1 == null)
+      {
+        throw new KeyAgreementException("missing message (1)");
+      }
+
+    ZZ = m1.modPow(B.getX(), B.getParams().getP()); // ZZ = (ya ^ xb) mod p
+
+    complete = true;
+    return null;
+  }
+}