Jonathan A. Poritz

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The pervasive interconnection of systems throughout the world has given computer services a significant socioeconomic value that both accidental faults and malicious activity can affect. The classical approach to security has mostly consisted of trying to prevent bad things from happening-by developing systems without vulnerabilities, for example, or by(More)
The <i>Trusted Computing Group</i> (TCG) is an industry consortium which has invested in the design of a small piece of hardware (roughly a smartcard), called a <i>Trusted Platform Module</i> (TPM), and associated APIs and protocols which are supposed to help increase the reliability of TPM-endowed computing platforms (<i>trusted platforms</i>). The TCG(More)
This article may be used for research, teaching and private study purposes. Any substantial or systematic reproduction, redistribution , reselling , loan or sub-licensing, systematic supply or distribution in any form to anyone is expressly forbidden. The publisher does not give any warranty express or implied or make any representation that the contents(More)
This document describes the designs of a generic distributed certification authority and of a trusted party for optimistic fair exchange that are based on fault-tolerant middle-ware for service replication. It also discusses other uses of the replication middleware for implementing trusted services. It may serve as a blueprint for building generic trusted(More)
This paper analyses the allocative properties of price cap regulation under very general hypotheses on the nature of society's preferences. We propose a generalised form of price cap formula (GPC) and we show that it ensures the convergence to optimal (second best) prices in the long-run equilibrium for virtually any form of the welfare function. In(More)
The pervasive interconnection of systems all over the world has given computer services a significant socioeconomic value, which can be affected both by accidental faults and by malicious activity. It would be appealing to address both problems in a seamless manner, through a common approach to security and dependability. This is the proposal of 'intrusion(More)
I describe a new formalization for computation which is similar to traditional circuit models but which depends upon the choice of a family of [semi]groups – essentially, a choice of the structure group of the universe of the computation. Choosing the symmetric groups results in the reversible version of classical computation; the unitary groups give(More)