Clark D. Thomborson

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The relation of an integer program to its rational relaxation has been the subject of considerable interest [l], [5], [11]. Such efforts fall into two categories: (1) Showing existence results for feasible solutions to an integer program in terms of the solution to its rational relaxation, and (2) Using the information derived from the solution of the(More)
It has become common to distribute software in forms that are isomorphic to the original source code. An important example is Java bytecode. Since such codes are easy to decompile, they increase the risk of malicious reverse engineering attacks.In this paper we describe the design of a Java code obfuscator, a tool which - through the application of code(More)
Watermarking embeds a secret message into a cover message. In media watermarking the secret is usually a copyright notice and the cover a digital image. Watermarking an object discourages intellectual property theft, or when such theft has occurred, allows us to prove ownership.The Software Watermarking problem can be described as follows. Embed a structure(More)
We examine the problem of routing wires of a VLSI chip, where the pins to be connected are arranged in a regular rectangular array. We obtain tight bounds for the worst-case “channel-width” needed to route ann×n array, and develop provably good heuristics for the general case. Single-turn routings are proved to be near-optimal in the worst-case. A central(More)
To ensure platform independence, mobile programs are distributed in forms that are isomorphic to the original source code. Such codes are easy to decompile, and hence they increase the risk of malicious reverse engineering attacks. Code obfuscation is one of several techniques which has been proposed to alleviate this situation. An obfuscator is a tool(More)
We identify three types of attack on the intellectual property contained in software, and three corresponding technical defenses. A potent defense against reverse engineering is obfuscation, a process that renders software unintelligible but still functional. A defense against software piracy is watermarking, a process that makes it possible to determine(More)
In the paper, we analyze the computational power of 2 and 3-dimensional processor arrays that contain a potentially large number of faults. We consider both a random a and worst-case fault model, and we prove that in either scenario, low-dimensional arrays are surprisingly fault-tolerant. For example, we show how to emulate an n e x n m fault-free array on(More)