Network Based Packet Watermarking Using TCP/IP Protocol Suite

Abstract

Watermarking is de ned as the art and science of embedding information in some cover. It takes one piece of information and embeds it within another. Mostly digital data is used for embedding. In this paper, we present a way to embed this digital information into the data packet. TCP/IP packets are transmitted over a network in large quantity. Within TCP/IP header there are number of elds that are not used for normal transmission or are \optional" elds which can be used by the sender of the datagrams. An analysis of the areas of a typical IP header shows that there are few elds which are either unused or optional reveals many possibilities where data can be stored and transmitted. Options eld of IP header is one of those elds. By embedding information in the options eld of IP packet, we can make use of unused eld of the IP header and can transmit our digital data within TCP/IP packets from sender to the receiver. One advantage of transmitting data in the header is that intruders will not have any idea that data is transmitted in the header, intruders will concentrate only on the payload of the packet. In order to implement this idea we will make our packet(which contains hidden data)to look like as normal packet(which does not contain hidden data) so that intruders will not be able to identify that our packet contains hidden data. Encryption and compression however are optional in performing watermarking, but by making use of such techniques the security in the design can be incorporated. Challenges like loss of packets and many others are also handled in the design.