Experience of Implementation of the Protocol TLS 1.3 Verification

This paper presents the experience of verifying server implementations of the TLS cryptographic protocol version 1.3. TLS is a widely used cryptographic protocol designed to create secure data transmission channels and provides the necessary functionality for this: confidentiality of the transmitted data, data integrity, and authentication of the parties. The new version 1.3 of the TLS protocol was introduced in August 2018 and has a number of significant differences compared to the previous version 1.2. A number of TLS developers have already included support for the latest version in their implementations. These circumstances make it relevant to do research in the field of verification and security of the new TLS protocol implementations. We used a new test suite for verifying implementations of the TLS 1.3 for compliance with Internet specifications, developed on the basis of the RFC8446, using UniTESK technology and mutation testing methods. The current work is part of the TLS 1.3 protocol verification project and covers some of the additional functionality and optional protocol extensions. To test implementations for compliance with formal specifications, UniTESK technology is used, which provides testing automation tools based on the use of finite state machines. The states of the system under test define the states of the state machine, and the test effects are the transitions of this machine. When performing a transition, the specified impact is passed to the implementation under test, after which the implementation's reactions are recorded and a verdict is automatically made on the compliance of the observed behavior with the specification. Mutational testing methods are used to detect non-standard behavior of the system under test by transmitting incorrect data. Some changes are made to the protocol exchange flow created in accordance with the specification: either the values of the message fields formed on the basis of the developed protocol model are changed, or the order of messages in the exchange flow is changed. The protocol model allows one to make changes to the data flow at any stage of the network exchange, which allows the test scenario to pass through all the significant states of the protocol and in each such state to test the implementation in accordance with the specified program. So far, several implementations have been found to deviate from the specification. The presented approach has proven effective in several of our projects when testing network protocols, providing detection of various deviations from the specification and other errors.

Testing Asynchronous Reactive Systems: Beyond the ioco framework

Manual testing can be rather time consuming and prone to errors specially when testing asynchronous reactive systems. Model based testing is a well-established approach to verify reactive systems specified by input output labeled transition systems (IOLTSs). One of the challenges stemming from model based testing is verifying conformance and, also, generating test suites, primarily when completeness is a required property. In order to check whether an implementation under test is in compliance with its respective specification one resorts to some form of conformance relation that guarantees the expected behavior of the implementations, given the behavior of the specification. The ioco relation is an example of such a conformance relation. In this work we study another conformance relation based on formal languages. We also investigate how to generate finite and complete test suites for IOLTS models, and discuss the complexity of the test generation mechanism under this new conformance relation. We also show that ioco is a special case of this new conformance relation. Further, we relate our contributions to more recent works, accommodating the restrictions of their classes of fault models as special cases, and we expose the complexity of generating any complete test suite that must satisfy their restrictions.

A Synchronized Test Control Execution Model of Distributed Systems

Conformance testing may be seen as mean to execute an IUT (implementation under test) by carrying out test cases in order to observe whether the behavior of the IUT is conforming to its specifications. However, the development of distributed testing frameworks is more complex and the implementation of the parallel testing components (PTCs) should take into consideration the mechanisms and functions required to support interaction during PTC communication. In this article, the authors present another way to control the test execution of PTCs by introducing synchronization messages into the local test sequences. Then, they suggest an agent-based simulation to implement synchronized local test sequences and resolve the problem of control and synchronization.

Verification of security properties of the TLS 1.3 extensions

This paper presents the experience of verifying server implementations of the TLS cryptographic protocol version 1.3. TLS is a widely used cryptographic protocol designed to create secure data transmission channels and provides the necessary functionality for this: confidentiality of the transmitted data, data integrity, and authentication of the parties. The new version 1.3 of the TLS protocol was introduced in August 2018 and has a number of significant differences compared to the previous version 1.2. A number of TLS developers have already included support for the latest version in their implementations. These circumstances make it relevant to do research in the field of verification and security of the new TLS protocol implementations. We used a new test suite for verifying implementations of the TLS 1.3 for compliance with Internet specifications, developed on the basis of the RFC8446, using UniTESK technology and mutation testing methods. The current work is part of the TLS 1.3 protocol verification project and covers some of the additional functionality and optional protocol extensions. To test implementations for compliance with formal specifications, UniTESK technology is used, which provides testing automation tools based on the use of finite state machines. The states of the system under test define the states of the state machine, and the test effects are the transitions of this machine. When performing a transition, the specified impact is passed to the implementation under test, after which the implementation's reactions are recorded and a verdict is automatically made on the compliance of the observed behavior with the specification. Mutational testing methods are used to detect non-standard behavior of the system under test by transmitting incorrect data. Some changes are made to the protocol exchange flow created in accordance with the specification: either the values of the message fields formed on the basis of the developed protocol model are changed, or the order of messages in the exchange flow is changed. The protocol model allows one to make changes to the data flow at any stage of the network exchange, which allows the test scenario to pass through all the significant states of the protocol and in each such state to test the implementation in accordance with the specified program. So far, several implementations have been found to deviate from the specification. The presented approach has proven effective in several of our projects when testing network protocols, providing detection of various deviations from the specification and other errors.

Side Channel Assessment Platforms and Tools for Ubiquitous Systems

Side Channel Attacks are nowadays considered a serious risk for many security products and ubiquitous devices. Strong security solution providers need to evaluate their implementations against such attacks before publishing them on the market, thus performing a thorough assessment. However, this procedure is not straightforward and even with the appropriate equipment, it may require considerable time to provide results due to the slow process of collecting measurements (traces) and the inflexible way of controlling the tested implementation. In this chapter, we explore and overview the trace collection landscape for generic devices under test (including ubiquitous systems) highlighting and overviewing the latest trace collection toolsets and their shortcomings, but also proposing a trace collection approach that can be applied on the most recent, open source toolsets. We showcase our proposed approach on the FlexLeco project architecture, which we have developed in our lab, and manage to practically describe how an evaluator using the proposed methodology can collect traces easily and quickly without the need to completely redesign a control mechanism for the implementation under test.

Test Case Generation Method for Increasing Software Reliability in Safety-Critical Embedded Systems

Finite-state machines (FSMs) and the W method have been widely used in software testing. However, the W method fails to detect post-processing errors in the implementation under test (IUT) because it ends testing when it encounters a previously visited state. To alleviate this issue, we propose an enhanced fault-detection W method. The proposed method does not stop the test, even if it has reached a previously visited state; it continues to test and check the points that the W method misses. Through various case studies, we demonstrated software testing using the W method and the proposed method. From the results, it can be inferred that the proposed method can more explicitly determine the consistency between design and implementation, and it is a better option for testing larger software. Unfortunately, the testing time of the proposed method is approximately 1.4 times longer than that of the W method because of the added paths. However, our method is more appropriate than the W method for software testing in safety-critical systems, even if this method is time consuming. This is because the error-free characteristics of a safety-critical system are more important than anything else. As a result, our method can be used to increase software reliability in safety-critical embedded systems.

A Synchronized Test Control Execution Model of Distributed Systems

Conformance testing may be seen as mean to execute an IUT (implementation under test) by carrying out test cases in order to observe whether the behavior of the IUT is conforming to its specifications. However, the development of distributed testing frameworks is more complex and the implementation of the parallel testing components (PTCs) should take into consideration the mechanisms and functions required to support interaction during PTC communication. In this article, the authors present another way to control the test execution of PTCs by introducing synchronization messages into the local test sequences. Then, they suggest an agent-based simulation to implement synchronized local test sequences and resolve the problem of control and synchronization.

An Introductory Study on an Architecture-Based Software Product Line Test Generation Method

Architecture-based testing allows test engineers to focus on the structure of complicated software and the interactions between software components that constitute the architecture of a software product. By observing and controlling the connections and interactions between components of complex or large systems during software testing, architecture-based testing can detect and localize such faults at those locations. The complexity of software product line testing is high because an implementation under test contains variability given the different binding times and is used by multiple products. This paper introduces how architecture-based testing is applied to test generation for a software product line and examines the strengths of the proposed method against existing software product line testing methods. The paper also illustrates the use of product line architecture and architectural artifacts to generate product line interaction tests. It was found that architecture-based testing can be applied to software product line test generation by tailoring it to deal with variability and product-line specific processes. The results of a comparison with existing methods show that architecture-based software product line test generation provides better capabilities in terms of variability in the testing stage, the explicit formation and application of binding, test coverage, and architectural awareness.

Metamorphic Relations Based Test Oracles for Image Processing Applications

Evaluation of output images carrying visual semantics is a challenging task which is carried out by domain experts through visual inspection. Automatic test oracle is required to augment the test oracle problem and to eliminate the manual efforts. Metamorphic testing is an effective technique to alleviate these problems. In this paper, the authors have demonstrated that how inherent properties of implementation under test can be used to generate an automatic test oracle for image processing applications. Metamorphic testing is a general technique in which follow-up test cases are generated using a transformation function and the anticipated output is evaluated. They have used some general metamorphic relations and also designed some algorithm specific metamorphic relations for morphological image operations. Selection of metamorphic relations is the most important step and the authors have analyzed relative effectiveness of different metamorphic relations using mutation analysis. The results show metamorphic testing is a very effective technique to automate output images evaluation and to alleviate oracle problem.

Metamorphic Relations Based Test Oracles for Image Processing Applications

Evaluation of output images carrying visual semantics is a challenging task which is carried out by domain experts through visual inspection. Automatic test oracle is required to augment the test oracle problem and to eliminate the manual efforts. Metamorphic testing is an effective technique to alleviate these problems. In this paper, the authors have demonstrated that how inherent properties of implementation under test can be used to generate an automatic test oracle for image processing applications. Metamorphic testing is a general technique in which follow-up test cases are generated using a transformation function and the anticipated output is evaluated. They have used some general metamorphic relations and also designed some algorithm specific metamorphic relations for morphological image operations. Selection of metamorphic relations is the most important step and the authors have analyzed relative effectiveness of different metamorphic relations using mutation analysis. The results show metamorphic testing is a very effective technique to automate output images evaluation and to alleviate oracle problem.