112 research outputs found
Principles of Contract Languages:Dagstuhl Seminar 22451
This report documents the program and the outcomes of Dagstuhl Seminar 22451 "Principles of Contract Languages". At the seminar, participants discussed the fundamental aspects of software contracts. Topics included the format and expressiveness of contracts, their use cases in software development and analysis, and contract composition and decomposition
Certification of Real Inequalities -- Templates and Sums of Squares
We consider the problem of certifying lower bounds for real-valued
multivariate transcendental functions. The functions we are dealing with are
nonlinear and involve semialgebraic operations as well as some transcendental
functions like , , , etc. Our general framework is to use
different approximation methods to relax the original problem into polynomial
optimization problems, which we solve by sparse sums of squares relaxations. In
particular, we combine the ideas of the maxplus estimators (originally
introduced in optimal control) and of the linear templates (originally
introduced in static analysis by abstract interpretation). The nonlinear
templates control the complexity of the semialgebraic relaxations at the price
of coarsening the maxplus approximations. In that way, we arrive at a new -
template based - certified global optimization method, which exploits both the
precision of sums of squares relaxations and the scalability of abstraction
methods. We analyze the performance of the method on problems from the global
optimization literature, as well as medium-size inequalities issued from the
Flyspeck project.Comment: 27 pages, 3 figures, 4 table
A STATISTICAL APPROACH FOR PACKER IDENTIFICATION
Most of modern malware are packed by packers which automatically generate a lot of obfuscation techniques to defeat the anti-virus software. To identify packer, most of industry approaches still adopt the well-known technique of signature matching which can be easily evaded. This paper studies the new approach of applying a statistical approach to tackle this problem. We propose a new weight for extracting what obfuscation techniques might be more favourable in packers. We call it obfuscation technique frequency-inverse packer frequency ( ). As the term implies, calculates values for each obfuscation techniques in a packer through an inverse proportion of the frequency of the obfuscation technique in a particular packer to the percentage of packers the obfuscation technique appears in. Obfuscation techniques with high value show a strong relationship with the packer they appear in. Based on this weight, packer is represented by a vector of . Then the used packer is identified by measuring the similarity between vectors of packer and targeted file. For checking the accuracy of our approach, we have performed the experiments of identifying packer on 200 real-world malware for comparing between our approach with the binary signature technique adopted in CFF Explorer. The result shows that our technique produces the better detection
Removing Algebraic Data Types from Constrained Horn Clauses Using Difference Predicates
We address the problem of proving the satisfiability of Constrained Horn
Clauses (CHCs) with Algebraic Data Types (ADTs), such as lists and trees. We
propose a new technique for transforming CHCs with ADTs into CHCs where
predicates are defined over basic types, such as integers and booleans, only.
Thus, our technique avoids the explicit use of inductive proof rules during
satisfiability proofs. The main extension over previous techniques for ADT
removal is a new transformation rule, called differential replacement, which
allows us to introduce auxiliary predicates corresponding to the lemmas that
are often needed when making inductive proofs. We present an algorithm that
uses the new rule, together with the traditional folding/unfolding
transformation rules, for the automatic removal of ADTs. We prove that if the
set of the transformed clauses is satisfiable, then so is the set of the
original clauses. By an experimental evaluation, we show that the use of the
differential replacement rule significantly improves the effectiveness of ADT
removal, and we show that our transformation-based approach is competitive with
respect to a well-established technique that extends the CVC4 solver with
induction.Comment: 10th International Joint Conference on Automated Reasoning (IJCAR
2020) - version with appendix; added DOI of the final authenticated Springer
publication; minor correction
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