Formal Verification of Security Protocol Implementations: A Survey

Automated formal verification of security protocols has been mostly focused on analyzing high-level abstract models which, however, are significantly different from real protocol implementations written in programming languages. Recently, some researchers have started investigating techniques that bring automated formal proofs closer to real implementations. This paper surveys these attempts, focusing on approaches that target the application code that implements protocol logic, rather than the libraries that implement cryptography. According to these approaches, libraries are assumed to correctly implement some models. The aim is to derive formal proofs that, under this assumption, give assurance about the application code that implements the protocol logic. The two main approaches of model extraction and code generation are presented, along with the main techniques adopted for each approac

Collaborative models for autonomous systems controller synthesis

Funding: UK EPSRC grants EP/N508792/1, EP/N007565 and EC/P51133X/1.We show how detailed simulation models and abstract Markov models can be developed collaboratively to generate and implement effective controllers for autonomous agent search and retrieve missions. We introduce a concrete simulation model of an Unmanned Aerial Vehicle (UAV). We then show how the probabilistic model checker PRISM is used for optimal strategy synthesis for a sequence of scenarios relevant to UAVs and potentially other autonomous agent systems. For each scenario we demonstrate how it can be modelled using PRISM, give model checking statistics and present the synthesised optimal strategies. We then show how our strategies can be returned to the controller for the simulation model and provide experimental results to demonstrate the effectiveness of one such strategy. Finally we explain how our models can be adapted, using symmetry, for use on larger search areas, and demonstrate the feasibility of this approach.Publisher PDFPeer reviewe

Die Integration von Verifikation und Test in Übersetzungssysteme

In dieser Arbeit wird die Architektur für einen Compiler vorgestellt, der die Korrektheit der übersetzten Quellen als Teil des Übersetzungsvorgangs überprüfen kann. Dabei soll es möglich sein, verschiedene Methoden, wie etwa formaler Test und formaler Beweis, einzusetzen, um die Korrektheit nachzuweisen. Ein vollautomatischer Nachweis ist sehr aufwendig und häufig auch gar nicht möglich. Es ist also nicht praktikabel, aus Spezifikation und Programm die Korrektheit automatisch abzuleiten. Wir erweitern daher die Sprache um Korrektheitsnachweise (justifications), die der Benutzer in den Quelltext einfügen muß ("literate justification"). Je nach gewählter Methode muß der Benutzer den Korrektheitsnachweis mehr oder weniger genau ausführen. Durch die Einführung der Korrektheitsnachweise muß der Übersetzer Beweise nur noch überprüfen anstatt sie automatisch abzuleiten. Die Überprüfung der Korrektheitsnachweise kann in den Übersetzer integriert werden oder an ein externes Werkzeug delegiert werden. Ein externes Werkzeug erlaubt die Einbindung bereits existierender Werkzeuge, aber auch eine Neuentwicklung eigener Werkzeuge ist möglich. Wir zeigen am Beispiel eines taktischen Theorembeweisers, daß eine Eigenentwicklung nicht unbedingt aufwendiger ist als die Anpassung eines vorhandenen Werkzeugs. Um Tests während der Übersetzung durchführen zu können, muß ein Interpreter zur Verfügung stehen. Die Ausführung ungetesteten Codes birgt allerdings auch Sicherheitsprobleme. Wir diskutieren verschiedene Möglichkeiten, mit diesem Problem umzugehen. Der Korrektheit einer Übersetzungseinheit entspricht in der Semantik die Konsistenz einer algebraischen Spezifikation. Wir betrachten zwei Beweismethoden: zum einen durch Konstruktion eines Modells und zum andern durch Nachweis einer korrektheitserhaltenden Relation. Die Beweisverpflichtungen ergeben sich zunächst aus der Beweismethode, außerdem werden Beweisverpflichtungen eingeführt, um die Korrektheit von zusammengesetzten (modularen) Programmen zuzusichern. Die in dieser Arbeit beschriebene Architektur ist prototypisch implementiert worden. Dazu wurde das Opal-System um Elemente zur Spezifikation und zur Beschreibung von Korektheitsnachweisen erweitert. In der Arbeit werden einige kurze Beispiele vorgeführt. Der Opal/J-Prototyp ist seit Version 2.3e Teil der Opal-Distribution.In this thesis we present a compiler architecture that enables the compiler to check the correctness of the source code as part of the compilation process. It allows to perform these correctness checks with different methods, in particular formal testing and formal proof. A fully automated check is very expensive and often impossible. Hence, it is not feasible to check correctness automatically with the help of specification and implementation. We extend the programming language by (correctness) justifications that the user must insert into the source code ("literate justification"). Depending on the chosen justification method the user must work out the justification in more or less detail. The introduction of justifications changes the compiler's task from deriving a correctness proof by itself to checking a correctness proof provided by the user. The correctness check for justifications can be integrated into the compiler or delegated to an external tool. An external tool allows the integration of existing tools but the development of specialized tools is also possible. The example development of a specialized tactical theorem-prover shows that the development of a specialized tool is not necessarily more expensive than the adaptation of an existing tool. For test execution during the compilation an interpreter must be available. The execution of untested code causes security risks. We discuss different possibilities to deal with this problem. The correctnessof a compilation unit corresponds to the consistency of an algebraic specification. We study two proof methods: either by construction of a model or by establishing a correctness-preserving relation. The proofo bligations result from the proof method, in addition proof obligations arei ntroduced to ensure the correctness of modular programs. The compiler architecture described in this thesis has been prototypically implemented. The Opal system has been extended with language elements to denote specifications and (correctness) justifications. The thesis presents some short examples. The Opal/J prototype is part of the Opal distribution since version 2.3e

On Modularity In Abstract State Machines

In the field of model based formal methods we investigate the Abstract State Machine (ASM) modularity features. With the growing complexity of systems and the experience gained in more than thirty years of ASM method application a need for more manageable models emerged. We mainly investigate the notion of modules in ASMs as independent interacting components and the ability to identify portions of the machine state with the aim of improving the modelling process. In this thesis we provide a language level semantically well defined solution for (1) the definition of ASM modules as independent services and their communication behaviour; (2) a new construct that operates on the global state of an ASM machine that ease the management of state partitions and their identification; (3) a novel transition rule for the management of computations providing different execution strategies and putting termination condition for the machine inside the specification; (4) a data definition convention along with a new transition rule for their manipulation via pattern matching. In our work we build upon CoreASM, a well-known extensible modelling framework and tool environment for ASMs. The semantic of our modularity constructs is compatible with the one defined for the CoreASM interpreter. This ease the implementation of extension plugins for tool support of modularity features. A real world system use case ground model ends the thesis exemplifying the practical usage of our modularity constructs

Fundamental Approaches to Software Engineering

This open access book constitutes the proceedings of the 25th International Conference on Fundamental Approaches to Software Engineering, FASE 2022, which was held during April 4-5, 2022, in Munich, Germany, as part of the European Joint Conferences on Theory and Practice of Software, ETAPS 2022. The 17 regular papers presented in this volume were carefully reviewed and selected from 64 submissions. The proceedings also contain 3 contributions from the Test-Comp Competition. The papers deal with the foundations on which software engineering is built, including topics like software engineering as an engineering discipline, requirements engineering, software architectures, software quality, model-driven development, software processes, software evolution, AI-based software engineering, and the specification, design, and implementation of particular classes of systems, such as (self-)adaptive, collaborative, AI, embedded, distributed, mobile, pervasive, cyber-physical, or service-oriented applications

Efficient Security Protocols for Constrained Devices

During the last decades, more and more devices have been connected to the Internet.Today, there are more devices connected to the Internet than humans.An increasingly more common type of devices are cyber-physical devices.A device that interacts with its environment is called a cyber-physical device.Sensors that measure their environment and actuators that alter the physical environment are both cyber-physical devices.Devices connected to the Internet risk being compromised by threat actors such as hackers.Cyber-physical devices have become a preferred target for threat actors since the consequence of an intrusion disrupting or destroying a cyber-physical system can be severe.Cyber attacks against power and energy infrastructure have caused significant disruptions in recent years.Many cyber-physical devices are categorized as constrained devices.A constrained device is characterized by one or more of the following limitations: limited memory, a less powerful CPU, or a limited communication interface.Many constrained devices are also powered by a battery or energy harvesting, which limits the available energy budget.Devices must be efficient to make the most of the limited resources.Mitigating cyber attacks is a complex task, requiring technical and organizational measures.Constrained cyber-physical devices require efficient security mechanisms to avoid overloading the systems limited resources.In this thesis, we present research on efficient security protocols for constrained cyber-physical devices.We have implemented and evaluated two state-of-the-art protocols, OSCORE and Group OSCORE.These protocols allow end-to-end protection of CoAP messages in the presence of untrusted proxies.Next, we have performed a formal protocol verification of WirelessHART, a protocol for communications in an industrial control systems setting.In our work, we present a novel attack against the protocol.We have developed a novel architecture for industrial control systems utilizing the Digital Twin concept.Using a state synchronization protocol, we propagate state changes between the digital and physical twins.The Digital Twin can then monitor and manage devices.We have also designed a protocol for secure ownership transfer of constrained wireless devices. Our protocol allows the owner of a wireless sensor network to transfer control of the devices to a new owner.With a formal protocol verification, we can guarantee the security of both the old and new owners.Lastly, we have developed an efficient Private Stream Aggregation (PSA) protocol.PSA allows devices to send encrypted measurements to an aggregator.The aggregator can combine the encrypted measurements and calculate the decrypted sum of the measurements.No party will learn the measurement except the device that generated it

Fundamental Approaches to Software Engineering

This open access book constitutes the proceedings of the 25th International Conference on Fundamental Approaches to Software Engineering, FASE 2022, which was held during April 4-5, 2022, in Munich, Germany, as part of the European Joint Conferences on Theory and Practice of Software, ETAPS 2022. The 17 regular papers presented in this volume were carefully reviewed and selected from 64 submissions. The proceedings also contain 3 contributions from the Test-Comp Competition. The papers deal with the foundations on which software engineering is built, including topics like software engineering as an engineering discipline, requirements engineering, software architectures, software quality, model-driven development, software processes, software evolution, AI-based software engineering, and the specification, design, and implementation of particular classes of systems, such as (self-)adaptive, collaborative, AI, embedded, distributed, mobile, pervasive, cyber-physical, or service-oriented applications