Electronic marking and identification techniques to discourage document copying

Modern computer networks make it possible to distribute documents quickly and economically by electronic means rather than by conventional paper means. However, the widespread adoption of electronic distribution of copyrighted material is currently impeded by the ease of illicit copying and dissemination. In this paper we propose techniques that discourage illicit distribution by embedding each document with a unique codeword. Our encoding techniques are indiscernible by readers, yet enable us to identify the sanctioned recipient of a document by examination of a recovered document. We propose three coding methods, describe one in detail, and present experimental results showing that our identification techniques are highly reliable, even after documents have been photocopied

The Minimum Shared Edges Problem on Grid-like Graphs

We study the NP-hard Minimum Shared Edges (MSE) problem on graphs: decide whether it is possible to route $p$ paths from a start vertex to a target vertex in a given graph while using at most $k$ edges more than once. We show that MSE can be decided on bounded (i.e. finite) grids in linear time when both dimensions are either small or large compared to the number $p$ of paths. On the contrary, we show that MSE remains NP-hard on subgraphs of bounded grids. Finally, we study MSE from a parametrised complexity point of view. It is known that MSE is fixed-parameter tractable with respect to the number $p$ of paths. We show that, under standard complexity-theoretical assumptions, the problem parametrised by the combined parameter $k$, $p$, maximum degree, diameter, and treewidth does not admit a polynomial-size problem kernel, even when restricted to planar graphs

Active Networks In Telephony

DARPA and the NSF are encouraging research on active router networks. By applying these concepts to telephony we: --- create a commodity, other than bandwidth, that a telephone network owner can sell, --- create new businesses for both equipment manufacturers and for network providers, --- provide local access with a distinct advantage over the current local operating companies, --- integrate the telephone network with the Internet so that traffic can move between the two, --- make it easier to assimilate new technology into the telephone network, and --- increase the rate of change in networks by reducing the need for standard protocols. To show the effect of active networks, the telephone network is divided into three layers corresponding to the user, the network manager, and the network owner. We give specific examples of the services and devices that are enabled at each layer. I. INTRODUCTION The current Internet protocols[1] are the result of the layered arch..

A Reliable Multicast Protocol With Delay Guarantees

The reliable multicast protocol guarantees that all receivers place the source messages in the same order. We hav e changed this protocol from an event driven protocol to a timed protocol in order to also guarantee that all of the receivers have the message by a dead line. In this work we present two modifications to the timed protocol that provide shorter deadlines. In the examples that we consider the tighter deadlines approach the nominal network delay. 1

An Internet Multicast System for the Stock Market

We are moving toward a distributed, international, twenty-four hour, electronic stock exchange. The exchange will use the global Internet, or internet technology. This system is a natural application of multicast because there are a large number of receivers that should receive the same information simultaneously. The data requirements for the stock exchange are discussed. The current multicast protocols lack the reliability, fairness, and scalability needed in this application. We describe a distributed architecture together with a reliable multicast protocol, a modification of the RMP protocol, that has characteristics appropriate for this application. The architecture is used in three applications: --- In the first, we construct a unified stock ticker of the transactions that are being conducted on the various physical and electronic exchanges. Our objective is to deliver the the same combined ticker reliably and simultaneously to all receivers, anywhere in the world. --- In the..