251 research outputs found
Actor Network Procedures as Psi-calculi for Security Ceremonies
The actor network procedures of Pavlovic and Meadows are a recent graphical
formalism developed for describing security ceremonies and for reasoning about
their security properties. The present work studies the relations of the actor
network procedures (ANP) to the recent psi-calculi framework. Psi-calculi is a
parametric formalism where calculi like spi- or applied-pi are found as
instances. Psi-calculi are operational and largely non-graphical, but have
strong foundation based on the theory of nominal sets and process algebras. One
purpose of the present work is to give a semantics to ANP through psi-calculi.
Another aim was to give a graphical language for a psi-calculus instance for
security ceremonies. At the same time, this work provides more insight into the
details of the ANPs formalization and the graphical representation.Comment: In Proceedings GraMSec 2014, arXiv:1404.163
A Fully Abstract Symbolic Semantics for Psi-Calculi
We present a symbolic transition system and bisimulation equivalence for
psi-calculi, and show that it is fully abstract with respect to bisimulation
congruence in the non-symbolic semantics.
A psi-calculus is an extension of the pi-calculus with nominal data types for
data structures and for logical assertions representing facts about data. These
can be transmitted between processes and their names can be statically scoped
using the standard pi-calculus mechanism to allow for scope migrations.
Psi-calculi can be more general than other proposed extensions of the
pi-calculus such as the applied pi-calculus, the spi-calculus, the fusion
calculus, or the concurrent constraint pi-calculus.
Symbolic semantics are necessary for an efficient implementation of the
calculus in automated tools exploring state spaces, and the full abstraction
property means the semantics of a process does not change from the original
Discovering, quantifying, and displaying attacks
In the design of software and cyber-physical systems, security is often
perceived as a qualitative need, but can only be attained quantitatively.
Especially when distributed components are involved, it is hard to predict and
confront all possible attacks. A main challenge in the development of complex
systems is therefore to discover attacks, quantify them to comprehend their
likelihood, and communicate them to non-experts for facilitating the decision
process. To address this three-sided challenge we propose a protection analysis
over the Quality Calculus that (i) computes all the sets of data required by an
attacker to reach a given location in a system, (ii) determines the cheapest
set of such attacks for a given notion of cost, and (iii) derives an attack
tree that displays the attacks graphically. The protection analysis is first
developed in a qualitative setting, and then extended to quantitative settings
following an approach applicable to a great many contexts. The quantitative
formulation is implemented as an optimisation problem encoded into
Satisfiability Modulo Theories, allowing us to deal with complex cost
structures. The usefulness of the framework is demonstrated on a national-scale
authentication system, studied through a Java implementation of the framework.Comment: LMCS SPECIAL ISSUE FORTE 201
Security-Oriented Formal Techniques
Security of software systems is a critical issue in a world where Information Technology is becoming more and more pervasive. The number of services for everyday life that are provided via electronic networks is rapidly increasing, as witnessed by the longer and longer list of words with the prefix "e", such as e-banking, e-commerce, e-government, where the "e" substantiates their electronic nature. These kinds of services usually require the exchange of sensible data and the sharing of computational resources, thus needing strong security requirements because of the relevance of the exchanged information and the very distributed and untrusted environment, the Internet, in which they operate. It is important, for example, to ensure the authenticity and the secrecy of the exchanged messages, to establish the identity of the involved entities, and to have guarantees that the different system components correctly interact, without violating the required global properties
A Spatial-Epistemic Logic for Reasoning about Security Protocols
Reasoning about security properties involves reasoning about where the
information of a system is located, and how it evolves over time. While most
security analysis techniques need to cope with some notions of information
locality and knowledge propagation, usually they do not provide a general
language for expressing arbitrary properties involving local knowledge and
knowledge transfer. Building on this observation, we introduce a framework for
security protocol analysis based on dynamic spatial logic specifications. Our
computational model is a variant of existing pi-calculi, while specifications
are expressed in a dynamic spatial logic extended with an epistemic operator.
We present the syntax and semantics of the model and logic, and discuss the
expressiveness of the approach, showing it complete for passive attackers. We
also prove that generic Dolev-Yao attackers may be mechanically determined for
any deterministic finite protocol, and discuss how this result may be used to
reason about security properties of open systems. We also present a
model-checking algorithm for our logic, which has been implemented as an
extension to the SLMC system.Comment: In Proceedings SecCo 2010, arXiv:1102.516
Formal security analysis of registration protocols for interactive systems: a methodology and a case of study
In this work we present and formally analyze CHAT-SRP (CHAos based
Tickets-Secure Registration Protocol), a protocol to provide interactive and
collaborative platforms with a cryptographically robust solution to classical
security issues. Namely, we focus on the secrecy and authenticity properties
while keeping a high usability. In this sense, users are forced to blindly
trust the system administrators and developers. Moreover, as far as we know,
the use of formal methodologies for the verification of security properties of
communication protocols isn't yet a common practice. We propose here a
methodology to fill this gap, i.e., to analyse both the security of the
proposed protocol and the pertinence of the underlying premises. In this
concern, we propose the definition and formal evaluation of a protocol for the
distribution of digital identities. Once distributed, these identities can be
used to verify integrity and source of information. We base our security
analysis on tools for automatic verification of security protocols widely
accepted by the scientific community, and on the principles they are based
upon. In addition, it is assumed perfect cryptographic primitives in order to
focus the analysis on the exchange of protocol messages. The main property of
our protocol is the incorporation of tickets, created using digests of chaos
based nonces (numbers used only once) and users' personal data. Combined with a
multichannel authentication scheme with some previous knowledge, these tickets
provide security during the whole protocol by univocally linking each
registering user with a single request. [..]Comment: 32 pages, 7 figures, 8 listings, 1 tabl
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