这是一个基于java编写的torrent的P2P源码

				package org.bouncycastle.asn1;
				
				import java.io.IOException;
				
				/**
				 * A NULL object.
				 */
				public class DERNull
				    extends ASN1Null
				{
				    byte[]  zeroBytes = new byte[0];
				
				    public DERNull()
				    {
				    }
				
				    void encode(
				        DEROutputStream  out)
				        throws IOException
				    {
				        out.writeEncoded(NULL, zeroBytes);
				    }
				    
					public boolean equals(
						Object o)
					{
				        if ((o == null) || !(o instanceof DERNull))
				        {
				            return false;
				        }
				        
						return true;
					}
				}