Lucia Draque Penso

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We study the problem of Secure Multi-party Computation (SMC) in a model where individual processes contain a tamper-proof security module, and introduce the TrustedPals framework, an efficient smart card based implementation of SMC for any number of participating entities in such a model. Security modules can be trusted by other processes and can establish(More)
We investigate computational models with stabilizing properties. Such models include e.g. the partially synchronous model [Dwork et al. 1988], where after some unknown global stabilization time the system complies to bounds on computing speeds and message delays, or the asynchronous model augmented with unreliable failure detectors [Chan-dra et al. 1996],(More)
In the k-set agreement problem [1], each process in a group starts with a private input value, communicates with the others, and then halts after choosing a private output value. Each process is required to choose some process's input, and at most k distinct values may be chosen. We consider this problem in an asynchronous message-passing system of n + 1(More)
We consider a connected undirected graph G(n, m) with n nodes and m edges. A k-dominating set D in G is a set of nodes having the property that every node in G is at most k edges away from at least one node in D. Finding a k-dominating set of minimum size is NP-hard. We give a new synchronous distributed algorithm to find a k-dominating set in G of size no(More)
We investigate the problem of detecting termination of a distributed computation in systems where processes can fail by crashing. Specifically, when the communication topology is fully connected, we describe a way to transform any termination detection algorithm A that has been designed for a failure-free environment into a termination detection algorithm B(More)
We investigate the problem of detecting termination of a distributed computation in asyn-chronous systems where processes can fail by crashing. More specifically, for both fully and arbitrarily connected communication topologies, we describe efficient ways to transform any fault-sensitive termination detection algorithm A, that has been designed for a(More)
This paper presents a modular redesign of TrustedPals, a smartcard-based security framework for solving secure multiparty computation (SMC). TrustedPals allows to reduce SMC to the problem of fault-tolerant consensus between smartcards. Within the redesign we investigate the problem of solving consensus in a general omission failure model augmented with(More)
We present a formal framework to talk and reason about dependable systems. The framework is based on three distinct classes of (system specification) properties we call safety, liveness and information flow. We discuss several examples of dependable systems within this framework and argue that these classes are sufficient to model the functional(More)
In the fair exchange problem, mutually untrusting parties must securely exchange digital goods. A fair exchange protocol must ensure that no combination of cheating or failures will result in some goods being delivered but not others, and that all goods will be delivered in the absence of cheating and failures. This paper proposes two novel randomized(More)