Copyright protection for the electronic distribution of text documents

Each copy of a text document can be made different in a nearly invisible way by repositioning or modifying the appearance of different elements of text, i.e., lines, words, or characters. A unique copy can be registered with its recipient, so that subsequent unauthorized copies that are retrieved can be traced back to the original owner. In this paper we describe and compare several mechanisms for marking documents and several other mechanisms for decoding the marks after documents have been subjected to common types of distortion. The marks are intended to protect documents of limited value that are owned by individuals who would rather possess a legal than an illegal copy if they can be distinguished. We will describe attacks that remove the marks and countermeasures to those attacks. An architecture is described for distributing a large number of copies without burdening the publisher with creating and transmitting the unique documents. The architecture also allows the publisher to determine the identity of a recipient who has illegally redistributed the document, without compromising the privacy of individuals who are not operating illegally. Two experimental systems are described. One was used to distribute an issue of the IEEE JOURNAL ON SELECTED AREAS IN COMMUNICATIONS, and the second was used to mark copies of company private memoranda

Proceedings of the Sixth International Workshop on Web Caching and Content Distribution

OVERVIEW The International Web Content Caching and Distribution Workshop (WCW) is a premiere technical meeting for researchers and practitioners interested in all aspects of content caching, distribution and delivery on the Internet. The 2001 WCW meeting was held on the Boston University Campus. Building on the successes of the five previous WCW meetings, WCW01 featured a strong technical program and record participation from leading researchers and practitioners in the field. This report includes all the technical papers presented at WCW'01. Note: Proceedings of WCW'01 are published by Elsevier. Hardcopies of these proceedings can be purchased through the workshop organizers. As a service to the community, electronic copies of all WCW'01 papers are accessible through Technical Report BUCS‐TR‐2001‐017, available from the Boston University Computer Science Technical Report Archives at http://www.cs.bu.edu/techreps. [Ed.note: URL outdated. Use http://www.bu.edu/cs/research/technical-reports/ or http://hdl.handle.net/2144/1455 in this repository to access the reports.]Cisco Systems; InfoLibria; Measurement Factory Inc; Voler

Tracing the Source of a Shredded Document

Consider two ordinary, seemingly identical plain paper shredders labeled A and B . When each of the two shredders is fed a blank sheet of paper, the resulting remnants are sufficiently similar that they are indistinguishable upon visual inspection. Now suppose that one of the shredders..

Tracing the source of a shredded document

Abstract. Consider two ordinary, seemingly identical plain paper shredders labeled A and B. When each of the two shredders is fed a blank sheet of paper, the resulting remnants are sufficiently similar that they are indistinguishable upon visual inspection. Now suppose that one of the shredders has been modified to introduce imperceptible variations in the size of each remnant it cuts. One of the shredders is then selected at random to destroy a blank sheet. By examination of the resulting paper remnants, can one determine if the sheet was shredded by A or B? In this paper we show how information hidden in the size and shape of shredded page remnants can be used to reveal the identity of the device used for shredding. We describe means for modifying shredders to introduce this hidden information. Experimental results reveal that properly embedded information can survive the severe nonlinear distortions introduced by the mechanics of paper shredding. Finally, we consider the question of whether paper shreds could reveal shredder identity even in the absence of device modifications

Performance Characterization of Traffic Equalizers on Heterogeneous Communication Links

Abstract. Aggregating the bandwidth of multiple low-cost physical communication links to form a single, higher capacity logical link is a common and inexpensive approach to increasing network performance. Aggregating or bonding links has traditionally been used in relatively static settings such as LAN-WAN interconnection, where the component links to be aggregated were typically identical (e.g., multiple T1 links) with very similar communication characteristics. However the emergence of multi-homed hosts and diverse access technologies (e.g., cable modem, wireless DSL) compel us to study the performance of aggregating the bandwidth of increasingly heterogeneous links. In this paper we examine the end-to-end performance of a single TCP connection with packets transmitted over multiple heterogeneous links. We describe a testbed we constructed, present empirical results, and introduce a new Linux-based traffic scheduler called wTEQL that we have developed to optimize the performance of TCP over multiple heterogeneous communication links. Finally, we present a novel analytical approach based on linear systems theory to characterize the performance of TCP over an inverse multiplexed channel with WRR scheduling over heterogeneous links. We believe that our model is the first to address how TCP throughput can collapse under mismatched packet scheduling policies.