8,737 research outputs found
Automated Certification of Authorisation Policy Resistance
Attribute-based Access Control (ABAC) extends traditional Access Control by
considering an access request as a set of pairs attribute name-value, making it
particularly useful in the context of open and distributed systems, where
security relevant information can be collected from different sources. However,
ABAC enables attribute hiding attacks, allowing an attacker to gain some access
by withholding information. In this paper, we first introduce the notion of
policy resistance to attribute hiding attacks. We then propose the tool ATRAP
(Automatic Term Rewriting for Authorisation Policies), based on the recent
formal ABAC language PTaCL, which first automatically searches for resistance
counter-examples using Maude, and then automatically searches for an Isabelle
proof of resistance. We illustrate our approach with two simple examples of
policies and propose an evaluation of ATRAP performances.Comment: 20 pages, 4 figures, version including proofs of the paper that will
be presented at ESORICS 201
Ackermannian and Primitive-Recursive Bounds with Dickson's Lemma
Dickson's Lemma is a simple yet powerful tool widely used in termination
proofs, especially when dealing with counters or related data structures.
However, most computer scientists do not know how to derive complexity upper
bounds from such termination proofs, and the existing literature is not very
helpful in these matters.
We propose a new analysis of the length of bad sequences over (N^k,\leq) and
explain how one may derive complexity upper bounds from termination proofs. Our
upper bounds improve earlier results and are essentially tight
CTL+FO Verification as Constraint Solving
Expressing program correctness often requires relating program data
throughout (different branches of) an execution. Such properties can be
represented using CTL+FO, a logic that allows mixing temporal and first-order
quantification. Verifying that a program satisfies a CTL+FO property is a
challenging problem that requires both temporal and data reasoning. Temporal
quantifiers require discovery of invariants and ranking functions, while
first-order quantifiers demand instantiation techniques. In this paper, we
present a constraint-based method for proving CTL+FO properties automatically.
Our method makes the interplay between the temporal and first-order
quantification explicit in a constraint encoding that combines recursion and
existential quantification. By integrating this constraint encoding with an
off-the-shelf solver we obtain an automatic verifier for CTL+FO
- …