Source for gnu.javax.net.ssl.provider.ClientDiffieHellmanPublic

   1: /* ClientDiffieHellmanPublic.java -- Client Diffie-Hellman value.
   2:    Copyright (C) 2006  Free Software Foundation, Inc.
   3: 
   4: This file is a part of GNU Classpath.
   5: 
   6: GNU Classpath is free software; you can redistribute it and/or modify
   7: it under the terms of the GNU General Public License as published by
   8: the Free Software Foundation; either version 2 of the License, or (at
   9: your option) any later version.
  10: 
  11: GNU Classpath is distributed in the hope that it will be useful, but
  12: WITHOUT ANY WARRANTY; without even the implied warranty of
  13: MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14: General Public License for more details.
  15: 
  16: You should have received a copy of the GNU General Public License
  17: along with GNU Classpath; if not, write to the Free Software
  18: Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301
  19: USA
  20: 
  21: Linking this library statically or dynamically with other modules is
  22: making a combined work based on this library.  Thus, the terms and
  23: conditions of the GNU General Public License cover the whole
  24: combination.
  25: 
  26: As a special exception, the copyright holders of this library give you
  27: permission to link this library with independent modules to produce an
  28: executable, regardless of the license terms of these independent
  29: modules, and to copy and distribute the resulting executable under
  30: terms of your choice, provided that you also meet, for each linked
  31: independent module, the terms and conditions of the license of that
  32: module.  An independent module is a module which is not derived from
  33: or based on this library.  If you modify this library, you may extend
  34: this exception to your version of the library, but you are not
  35: obligated to do so.  If you do not wish to do so, delete this
  36: exception statement from your version.  */
  37: 
  38: 
  39: package gnu.javax.net.ssl.provider;
  40: 
  41: import java.io.PrintWriter;
  42: import java.io.StringWriter;
  43: 
  44: import java.math.BigInteger;
  45: 
  46: import java.nio.ByteBuffer;
  47: 
  48: /**
  49:  * The client's explicit Diffie Hellman value.
  50:  *
  51:  * <pre>
  52: struct {
  53:   select (PublicValueEncoding) {
  54:     case implicit: struct { };
  55:     case explicit: opaque dh_Yc&lt;1..2^16-1&gt;;
  56:   } dh_public;
  57: } ClientDiffieHellmanPublic;</pre>
  58:  */
  59: public class ClientDiffieHellmanPublic extends ExchangeKeys implements Builder
  60: {
  61:   public ClientDiffieHellmanPublic(final ByteBuffer buffer)
  62:   {
  63:     super(buffer);
  64:   }
  65: 
  66:   public ClientDiffieHellmanPublic(final BigInteger Yc)
  67:   {
  68:     super(wrap(Yc));
  69:   }
  70: 
  71:   private static ByteBuffer wrap(BigInteger Yc)
  72:   {
  73:     byte[] b = Util.trim(Yc);
  74:     ByteBuffer ret = ByteBuffer.allocate(b.length + 2);
  75:     ret.putShort((short) b.length);
  76:     ret.put(b);
  77:     return (ByteBuffer) ret.rewind();
  78:   }
  79: 
  80:   public ByteBuffer buffer()
  81:   {
  82:     return (ByteBuffer) buffer.duplicate().rewind().limit(length());
  83:   }
  84: 
  85:   public BigInteger publicValue()
  86:   {
  87:     int len = length() - 2;
  88:     byte[] b = new byte[len];
  89:     buffer.position(2);
  90:     buffer.get(b);
  91:     buffer.rewind();
  92:     return new BigInteger(1, b);
  93:   }
  94: 
  95:   public void setPublicValue(final BigInteger Yc)
  96:   {
  97:     byte[] buf = Util.trim(Yc);
  98:     if (buffer.capacity() < buf.length + 2)
  99:       buffer = ByteBuffer.allocate(buf.length + 2);
 100:     buffer.putShort((short) buf.length);
 101:     buffer.put(buf);
 102:     buffer.rewind();
 103:   }
 104: 
 105:   public int length ()
 106:   {
 107:     return (buffer.getShort(0) & 0xFFFF) + 2;
 108:   }
 109: 
 110:   public String toString ()
 111:   {
 112:     return toString (null);
 113:   }
 114: 
 115:   public String toString (final String prefix)
 116:   {
 117:     StringWriter str = new StringWriter ();
 118:     PrintWriter out = new PrintWriter (str);
 119:     if (prefix != null) out.print (prefix);
 120:     out.println ("struct {");
 121:     if (prefix != null) out.print (prefix);
 122:     out.print ("  dh_Yc = ");
 123:     out.print (publicValue ().toString (16));
 124:     out.println (';');
 125:     if (prefix != null) out.print (prefix);
 126:     out.print ("} ClientDiffieHellmanPublic;");
 127:     return str.toString ();
 128:   }
 129: }