13,470 research outputs found
Combining STPA with SysML Modeling
System-Theoretic Process Analysis (STPA) is a technique, based on System-Theoretic Accident Model and Process (STAMP), to identify hazardous control actions, loss scenarios, and safety requirements. STPA is considered a rather complex technique and lacks formalism, but there exists a growing interest in using STPA in certifications of safety-critical systems development. SysML is a modeling language for systems engineering. It enables representing models for analysis, design, verification, and validation of systems. In particular, the free software TTool and the model-checker UPPAAL enable formal verification of SysML models. This paper proposes a method that combines STPA and SysML modeling activities in order to allow simulation and formal verification of systems' models. An automatic door system serves as example to illustrate the effectiveness of the proposed approach
Sciduction: Combining Induction, Deduction, and Structure for Verification and Synthesis
Even with impressive advances in automated formal methods, certain problems
in system verification and synthesis remain challenging. Examples include the
verification of quantitative properties of software involving constraints on
timing and energy consumption, and the automatic synthesis of systems from
specifications. The major challenges include environment modeling,
incompleteness in specifications, and the complexity of underlying decision
problems.
This position paper proposes sciduction, an approach to tackle these
challenges by integrating inductive inference, deductive reasoning, and
structure hypotheses. Deductive reasoning, which leads from general rules or
concepts to conclusions about specific problem instances, includes techniques
such as logical inference and constraint solving. Inductive inference, which
generalizes from specific instances to yield a concept, includes algorithmic
learning from examples. Structure hypotheses are used to define the class of
artifacts, such as invariants or program fragments, generated during
verification or synthesis. Sciduction constrains inductive and deductive
reasoning using structure hypotheses, and actively combines inductive and
deductive reasoning: for instance, deductive techniques generate examples for
learning, and inductive reasoning is used to guide the deductive engines.
We illustrate this approach with three applications: (i) timing analysis of
software; (ii) synthesis of loop-free programs, and (iii) controller synthesis
for hybrid systems. Some future applications are also discussed
ARPA Whitepaper
We propose a secure computation solution for blockchain networks. The
correctness of computation is verifiable even under malicious majority
condition using information-theoretic Message Authentication Code (MAC), and
the privacy is preserved using Secret-Sharing. With state-of-the-art multiparty
computation protocol and a layer2 solution, our privacy-preserving computation
guarantees data security on blockchain, cryptographically, while reducing the
heavy-lifting computation job to a few nodes. This breakthrough has several
implications on the future of decentralized networks. First, secure computation
can be used to support Private Smart Contracts, where consensus is reached
without exposing the information in the public contract. Second, it enables
data to be shared and used in trustless network, without disclosing the raw
data during data-at-use, where data ownership and data usage is safely
separated. Last but not least, computation and verification processes are
separated, which can be perceived as computational sharding, this effectively
makes the transaction processing speed linear to the number of participating
nodes. Our objective is to deploy our secure computation network as an layer2
solution to any blockchain system. Smart Contracts\cite{smartcontract} will be
used as bridge to link the blockchain and computation networks. Additionally,
they will be used as verifier to ensure that outsourced computation is
completed correctly. In order to achieve this, we first develop a general MPC
network with advanced features, such as: 1) Secure Computation, 2) Off-chain
Computation, 3) Verifiable Computation, and 4)Support dApps' needs like
privacy-preserving data exchange
Applying Formal Methods to Networking: Theory, Techniques and Applications
Despite its great importance, modern network infrastructure is remarkable for
the lack of rigor in its engineering. The Internet which began as a research
experiment was never designed to handle the users and applications it hosts
today. The lack of formalization of the Internet architecture meant limited
abstractions and modularity, especially for the control and management planes,
thus requiring for every new need a new protocol built from scratch. This led
to an unwieldy ossified Internet architecture resistant to any attempts at
formal verification, and an Internet culture where expediency and pragmatism
are favored over formal correctness. Fortunately, recent work in the space of
clean slate Internet design---especially, the software defined networking (SDN)
paradigm---offers the Internet community another chance to develop the right
kind of architecture and abstractions. This has also led to a great resurgence
in interest of applying formal methods to specification, verification, and
synthesis of networking protocols and applications. In this paper, we present a
self-contained tutorial of the formidable amount of work that has been done in
formal methods, and present a survey of its applications to networking.Comment: 30 pages, submitted to IEEE Communications Surveys and Tutorial
Exploratory Study of the Privacy Extension for System Theoretic Process Analysis (STPA-Priv) to elicit Privacy Risks in eHealth
Context: System Theoretic Process Analysis for Privacy (STPA-Priv) is a novel
privacy risk elicitation method using a top down approach. It has not gotten
very much attention but may offer a convenient structured approach and
generation of additional artifacts compared to other methods. Aim: The aim of
this exploratory study is to find out what benefits the privacy risk
elicitation method STPA-Priv has and to explain how the method can be used.
Method: Therefore we apply STPA-Priv to a real world health scenario that
involves a smart glucose measurement device used by children. Different kinds
of data from the smart device including location data should be shared with the
parents, physicians, and urban planners. This makes it a sociotechnical system
that offers adequate and complex privacy risks to be found. Results: We find
out that STPA-Priv is a structured method for privacy analysis and finds
complex privacy risks. The method is supported by a tool called XSTAMPP which
makes the analysis and its results more profound. Additionally, we learn that
an iterative application of the steps might be necessary to find more privacy
risks when more information about the system is available later. Conclusions:
STPA-Priv helps to identify complex privacy risks that are derived from
sociotechnical interactions in a system. It also outputs privacy constraints
that are to be enforced by the system to ensure privacy.Comment: author's post-prin
Proof Theory, Transformations, and Logic Programming for Debugging Security Protocols
We define a sequent calculus to formally specify, simulate, debug and verify security protocols. In our sequents we distinguish between the current knowledge of principals and the current global state of the session. Hereby, we can describe the operational semantics of principals and of an intruder in a simple and modular way. Furthermore, using proof theoretic tools like the analysis of permutability of rules, we are able to find efficient proof strategies that we prove complete for special classes of security protocols including Needham-Schroeder. Based on the results of this preliminary analysis, we have implemented a Prolog meta-interpreter which allows for rapid prototyping and for checking safety properties of security protocols, and we have applied it for finding error traces and proving correctness of practical examples
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