Characterizing intransitive noninterference for 3-domain security policies with observability

Abstract

As a final remark, we note that our adaptive control scheme is modular, that is the adaptive law and the control law are separated. Hence, one has the flexibility of modifying or adjusting one of these laws without affecting the other. Particularly, a least square based adaptive law can be used instead of the gradient algorithm, and parameter projection may be combined or replaced by another robustness modification technique. REFERENCES Characterizing Intransitive Noninterference for 3-Domain Security Policies With ObservabilityNejib Ben Hadj-Alouane, Stéphane Lafrance, Feng Lin, John Mullins, and Moez YeddesAbstract-This note introduces a new algorithmic approach to the problem of checking the property of intransitive noninterference (INI) using discrete-event systems (DESs) tools and concepts. INI property is widely used in formal verification of security problems in computer systems and protocols. The approach consists of two phases: First, a new property called -observability (observability based on a purge function) is introduced to capture INI. We prove that a system satisfies INI if and only if it is -observable. Second, a relation between -observability and -observability (observability as used in DES) is established by transforming the automaton modeling a system/protocol into an automaton where -observability (and, hence, -observability) can be determined. This allows us to check INI by checking -observability, which can be done efficiently. Our approach can be used for all systems/protocols with three domains or levels, which is sufficient for most noninterference problems for cryptographic protocols and systems.

Algorithmic Verification of Intransitive Noninterference for 3-domain Security Policies with a SAT Solver

“…Recently, in [13,14] for discrete event systems Nejib Ben Hadj-Alouane et al proposed an algorithmic approach to the verification of intransitive noninterference. The basic concept of their approach is to use an observability based on a purge function, called iP-observability, to capture intransitive noninterference, and reduce the checking of iP-observability to the checking of P-observability, which can be done efficiently.…”

“…At present, the absence of feasible algorithmic verification approaches is the main problem in checking intransitive noninterference. Prior to our work, only one rigorous algorithm has been proposed by Nejib Ben Hadj-Alouane in the literature [13,14] to check intransitive noninterference based on some necessary and sufficient conditions. Other algorithms, for example [8], only use a sufficient condition as a basis for checking intransitive noninterference.…”

An algorithmic approach to verification of intransitive non-interference in security policies

“…In this section, we briefly review intransitive non-interference in multi-level systems as well as its characterization as iP -observability introduced in [3]. The reader is refereed to [3] for more details.…”

“…• Σ • Σ R E = {e 3 • Σ S = {c 1 , c 2 , c 3 } since those are synchronization events between A and B;…”

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AbstractIn this paper, we generalize our algorithmic approach to the problem of verification of the property of intransitive non-interference (INI) using tools and concepts of discrete event systems (DES) that we first proposed in [3]. The reason that we are interested in INI is that it can be used to solve several important security problems in systems and protocols.

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