21,255 research outputs found
A proposal for broad spectrum proof certificates
International audienceRecent developments in the theory of focused proof systems provide flexible means for structuring proofs within the sequent calculus. This structuring is organized around the construction of ''macro'' level inference rules based on the ''micro'' inference rules which introduce single logical connectives. After presenting focused proof systems for first-order classical logics (one with and one without fixed points and equality) we illustrate several examples of proof certificates formats that are derived naturally from the structure of such focused proof systems. In principle, a proof certificate contains two parts: the first part describes how macro rules are defined in terms of micro rules and the second part describes a particular proof object using the macro rules. The first part, which is based on the vocabulary of focused proof systems, describes a collection of macro rules that can be used to directly present the structure of proof evidence captured by a particular class of computational logic systems. While such proof certificates can capture a wide variety of proof structures, a proof checker can remain simple since it must only understand the micro-rules and the discipline of focusing. Since proofs and proof certificates are often likely to be large, there must be some flexibility in allowing proof certificates to elide subproofs: as a result, proof checkers will necessarily be required to perform (bounded) proof search in order to reconstruct missing subproofs. Thus, proof checkers will need to do unification and restricted backtracking search
A framework for proof certificates in finite state exploration
Model checkers use automated state exploration in order to prove various
properties such as reachability, non-reachability, and bisimulation over state
transition systems. While model checkers have proved valuable for locating
errors in computer models and specifications, they can also be used to prove
properties that might be consumed by other computational logic systems, such as
theorem provers. In such a situation, a prover must be able to trust that the
model checker is correct. Instead of attempting to prove the correctness of a
model checker, we ask that it outputs its "proof evidence" as a formally
defined document--a proof certificate--and that this document is checked by a
trusted proof checker. We describe a framework for defining and checking proof
certificates for a range of model checking problems. The core of this framework
is a (focused) proof system that is augmented with premises that involve "clerk
and expert" predicates. This framework is designed so that soundness can be
guaranteed independently of any concerns for the correctness of the clerk and
expert specifications. To illustrate the flexibility of this framework, we
define and formally check proof certificates for reachability and
non-reachability in graphs, as well as bisimulation and non-bisimulation for
labeled transition systems. Finally, we describe briefly a reference checker
that we have implemented for this framework.Comment: In Proceedings PxTP 2015, arXiv:1507.0837
A Decentralised Digital Identity Architecture
Current architectures to validate, certify, and manage identity are based on
centralised, top-down approaches that rely on trusted authorities and
third-party operators. We approach the problem of digital identity starting
from a human rights perspective, with a primary focus on identity systems in
the developed world. We assert that individual persons must be allowed to
manage their personal information in a multitude of different ways in different
contexts and that to do so, each individual must be able to create multiple
unrelated identities. Therefore, we first define a set of fundamental
constraints that digital identity systems must satisfy to preserve and promote
privacy as required for individual autonomy. With these constraints in mind, we
then propose a decentralised, standards-based approach, using a combination of
distributed ledger technology and thoughtful regulation, to facilitate
many-to-many relationships among providers of key services. Our proposal for
digital identity differs from others in its approach to trust in that we do not
seek to bind credentials to each other or to a mutually trusted authority to
achieve strong non-transferability. Because the system does not implicitly
encourage its users to maintain a single aggregated identity that can
potentially be constrained or reconstructed against their interests,
individuals and organisations are free to embrace the system and share in its
benefits.Comment: 30 pages, 10 figures, 3 table
Defining the meaning of TPTP formatted proofs
International audienceThe TPTP library is one of the leading problem libraries in the automated theorem proving community. Over time, support was added for problems beyond those in first-order clausal form. TPTP has also been augmented with support for various proof formats output by theorem provers. Such proofs can also be maintained in the TSTP proof library. In this paper we propose an extension of this framework to support the semantic specification of the inference rules used in proofs
Checking Zenon Modulo Proofs in Dedukti
Dedukti has been proposed as a universal proof checker. It is a logical
framework based on the lambda Pi calculus modulo that is used as a backend to
verify proofs coming from theorem provers, especially those implementing some
form of rewriting. We present a shallow embedding into Dedukti of proofs
produced by Zenon Modulo, an extension of the tableau-based first-order theorem
prover Zenon to deduction modulo and typing. Zenon Modulo is applied to the
verification of programs in both academic and industrial projects. The purpose
of our embedding is to increase the confidence in automatically generated
proofs by separating untrusted proof search from trusted proof verification.Comment: In Proceedings PxTP 2015, arXiv:1507.0837
On the Security of the Automatic Dependent Surveillance-Broadcast Protocol
Automatic dependent surveillance-broadcast (ADS-B) is the communications
protocol currently being rolled out as part of next generation air
transportation systems. As the heart of modern air traffic control, it will
play an essential role in the protection of two billion passengers per year,
besides being crucial to many other interest groups in aviation. The inherent
lack of security measures in the ADS-B protocol has long been a topic in both
the aviation circles and in the academic community. Due to recently published
proof-of-concept attacks, the topic is becoming ever more pressing, especially
with the deadline for mandatory implementation in most airspaces fast
approaching.
This survey first summarizes the attacks and problems that have been reported
in relation to ADS-B security. Thereafter, it surveys both the theoretical and
practical efforts which have been previously conducted concerning these issues,
including possible countermeasures. In addition, the survey seeks to go beyond
the current state of the art and gives a detailed assessment of security
measures which have been developed more generally for related wireless networks
such as sensor networks and vehicular ad hoc networks, including a taxonomy of
all considered approaches.Comment: Survey, 22 Pages, 21 Figure
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