Biblio

Abstract We study the problem of selecting offsets of the traffic signals in a network of signalized intersections to reduce queues of vehicles at all intersections. The signals in the network have a common cycle time and a fixed timing plan. It is assumed that the exogenous demands are constant or periodic with the same period as the cycle time and the intersections are under-saturated. The resulting queuing processes are periodic. These periodic processes are approximated by sinusoids. The sinusoidal approximation leads to an analytical expression of the queue lengths at every intersection as a function of the demands and the vector of offsets. The optimum offset vector is the solution of a quadratically constrained quadratic program (QCQP), which is solved via its convex semidefinite relaxation. Unlike existing techniques, our approach accommodates networks with arbitrary topology and scales well with network size. We illustrate the result in two case studies. The first is an academic example previously proposed in the literature, and the second case study consists of an arterial corridor network in Arcadia, California.

We introduce a novel mathematical model that treats network security as a game between cyber attackers and network administrators. The model takes the form of a zero-sum repeated game where each sub-game corresponds to a possible state of the attacker. Our formulation views state as the set of compromised edges in a graph opposed to the more traditional node-based view. This provides a more expressive model since it allows the defender to anticipate the direction of attack. Both players move independently and in continuous time allowing for the possibility of one player moving several times before the other does. This model shows that defense-in-depth is not always a rational strategy for budget constrained network administrators. Furthermore, a defender can dissuade a rational attacker from attempting to attack a network if the defense budget is sufficiently high. This means that a network administrator does not need to make their system completely free of vulnerabilities, they only to ensure the penalties for being caught outweigh the potential rewards gained.

Nowadays the application of integrated management systems (IMS) attracts the attention of top management from various organizations. However, there is an important problem of running the security audits in IMS and realization of complex checks of different ISO standards in full scale with the essential reducing of available resources.

Similar to criminals in the physical world, cyber-criminals use a variety of illegal and immoral means to achieve monetary gains. Recently, malware known as ransomware started to leverage strong cryptographic primitives to hold victims' computer files "hostage" until a ransom is paid. Victims, with no way to defend themselves, are often advised to simply pay. Existing defenses against ransomware rely on ad-hoc mitigations that target the incorrect use of cryptography rather than generic live protection. To fill this gap in the defender's arsenal, we describe the approach, prototype implementation, and evaluation of a novel, automated, and most importantly proactive defense mechanism against ransomware. Our prototype, called PayBreak, effectively combats ransomware, and keeps victims' files safe. PayBreak is based on the insight that secure file encryption relies on hybrid encryption where symmetric session keys are used on the victim computer. PayBreak observes the use of these keys, holds them in escrow, and thus, can decrypt files that would otherwise only be recoverable by paying the ransom. Our prototype leverages low overhead dynamic hooking techniques and asymmetric encryption to realize the key escrow mechanism which allows victims to restore the files encrypted by ransomware. We evaluated PayBreak for its effectiveness against twenty hugely successful families of real-world ransomware, and demonstrate that our system can restore all files that are encrypted by samples from twelve of these families, including the infamous CryptoLocker, and more recent threats such as Locky and SamSam. Finally, PayBreak performs its protection task at negligible performance overhead for common office workloads and is thus ideally suited as a proactive online protection system.

Existing access control mechanisms are based on the concept of identity enrolment and recognition and assume that recognized identity is a synonym to ethical actions, yet statistics over the years show that the most severe security breaches are the results of trusted, identified, and legitimate users who turned into malicious insiders. Insider threat damages vary from intellectual property loss and fraud to information technology sabotage. As insider threat incidents evolve, there exist demands for a nonidentity-based authentication measure that rejects access to authorized individuals who have mal-intents of access. In this paper, we study the possibility of using the user's intention as an access control measure using the involuntary electroencephalogram reactions toward visual stimuli. We propose intent-based access control (IBAC) that detects the intentions of access based on the existence of knowledge about an intention. IBAC takes advantage of the robustness of the concealed information test to assess access risk. We use the intent and intent motivation level to compute the access risk. Based on the calculated risk and risk accepted threshold, the system makes the decision whether to grant or deny access requests. We assessed the model using experiments on 30 participants that proved the robustness of the proposed solution.

Data provenance describes how data came to be in its present form. It includes data sources and the transformations that have been applied to them. Data provenance has many uses, from forensics and security to aiding the reproducibility of scientific experiments. We present CamFlow, a whole-system provenance capture mechanism that integrates easily into a PaaS offering. While there have been several prior whole-system provenance systems that captured a comprehensive, systemic and ubiquitous record of a system's behavior, none have been widely adopted. They either A) impose too much overhead, B) are designed for long-outdated kernel releases and are hard to port to current systems, C) generate too much data, or D) are designed for a single system. CamFlow addresses these shortcoming by: 1) leveraging the latest kernel design advances to achieve efficiency; 2) using a self-contained, easily maintainable implementation relying on a Linux Security Module, NetFilter, and other existing kernel facilities; 3) providing a mechanism to tailor the captured provenance data to the needs of the application; and 4) making it easy to integrate provenance across distributed systems. The provenance we capture is streamed and consumed by tenant-built auditor applications. We illustrate the usability of our implementation by describing three such applications: demonstrating compliance with data regulations; performing fault/intrusion detection; and implementing data loss prevention. We also show how CamFlow can be leveraged to capture meaningful provenance without modifying existing applications.

Genetic data are important dataset utilised in genetic epidemiology to investigate biologically coded information within the human genome. Enormous research has been delved into in recent years in order to fully sequence and understand the genome. Personalised medicine, patient response to treatments and relationships between specific genes and certain characteristics such as phenotypes and diseases, are positive impacts of studying the genome, just to mention a few. The sensitivity, longevity and non-modifiable nature of genetic data make it even more interesting, consequently, the security and privacy for the storage and processing of genomic data beg for attention. A common activity carried out by geneticists is the association analysis between allele-allele, or even a genetic locus and a disease. We demonstrate the use of cryptographic techniques such as homomorphic encryption schemes and multiparty computations, how such analysis can be carried out in a privacy friendly manner. We compute a 3 × 3 contingency table, and then, genome analyses algorithms such as linkage disequilibrium (LD) measures, all on the encrypted domain. Our computation guarantees privacy of the genome data under our security settings, and provides up to 98.4% improvement, compared to an existing solution.

Vehicular Ad-Hoc Networks (VANET) are the creation of several vehicles communicating with each other in order to create a network capable of communication and data exchange. One of the most promising methods for security and trust amongst vehicular networks is the usage of Public Key Infrastructure (PKI). However, current implementations of PKI as a security solution for determining the validity and authenticity of vehicles in a VANET is not efficient due to the usage of large amounts of delay and computational overhead. In this paper, we investigate the potential of PKI when predictively and preemptively passing along certificates to roadside units (RSU) in an effort to lower delay and computational overhead in a dynamic environment. We look to accomplish this through utilizing fog computing and propose a new protocol to pass certificates along the projected path.

In this paper, we explore the usage of printed tags to authenticate products. Printed tags are a cheap alternative to RFID and other tag based systems and do not require specialized equipment. Due to the simplistic nature of such printed codes, many security issues like tag impersonation, server impersonation, reader impersonation, replay attacks and denial of service present in RFID based solutions need to be handled differently. We propose a cost-efficient scheme based on static tag based hash chains to address these security threats. We analyze the security characteristics of this scheme and compare it to other product authentication schemes that use RFID tags. Finally, we show that our proposed statically printed QR codes can be at least as secure as RFID tags.

Due to the proliferation of reprogrammable hardware, core designs built from modules drawn from a variety of sources execute with direct access to critical system resources. Expressing guarantees that such modules satisfy, in particular the dynamic conditions under which they release information about their unbounded streams of inputs, and automatically proving that they satisfy such guarantees, is an open and critical problem.,,To address these challenges, we propose a domain-specific language, named STREAMS, for expressing information-flow policies with declassification over unbounded input streams. We also introduce a novel algorithm, named SIMAREL, that given a core design C and STREAMS policy P, automatically proves or falsifies that C satisfies P. The key technical insight behind the design of SIMAREL is a novel algorithm for efficiently synthesizing relational invariants over pairs of circuit executions.,,We expressed expected behavior of cores designed independently for research and production as STREAMS policies and used SIMAREL to check if each core satisfies its policy. SIMAREL proved that half of the cores satisfied expected behavior, but found unexpected information leaks in six open-source designs: an Ethernet controller, a flash memory controller, an SD-card storage manager, a robotics controller, a digital-signal processing (DSP) module, and a debugging interface.

Over the last decade, a globalization of the software industry took place, which facilitated the sharing and reuse of code across existing project boundaries. At the same time, such global reuse also introduces new challenges to the software engineering community, with not only components but also their problems and vulnerabilities being now shared. For example, vulnerabilities found in APIs no longer affect only individual projects but instead might spread across projects and even global software ecosystem borders. Tracing these vulnerabilities at a global scale becomes an inherently difficult task since many of the existing resources required for such analysis still rely on proprietary knowledge representation. In this research, we introduce an ontology-based knowledge modeling approach that can eliminate such information silos. More specifically, we focus on linking security knowledge with other software knowledge to improve traceability and trust in software products (APIs). Our approach takes advantage of the Semantic Web and its reasoning services, to trace and assess the impact of security vulnerabilities across project boundaries. We present a case study, to illustrate the applicability and flexibility of our ontological modeling approach by tracing vulnerabilities across project and resource boundaries.

Many innovations in the field of cryptography have been made in recent decades, ensuring the confidentiality of the message's content. However, sometimes it's not enough to secure the message, and communicating parties need to hide the fact of the presence of any communication. This problem is solved by covert channels. A huge number of ideas and implementations of different types of covert channels was proposed ever since the covert channels were mentioned for the first time. The spread of the Internet and networking technologies was the reason for the use of network protocols for the invention of new covert communication methods and has led to the emergence of a new class of threats related to the data leakage via network covert channels. In recent years, web applications, such as web browsers, email clients and web messengers have become indispensable elements in business and everyday life. That's why ubiquitous HTTP messages are so useful as a covert information containers. The use of HTTP for the implementation of covert channels may increase the capacity of covert channels due to HTTP's flexibility and wide distribution as well. We propose a detailed analysis of all known HTTP covert channels and techniques of their detection and capacity limitation.

Vehicular ad-Hoc Networks (VANETs) have been promoted as a key technology that can provide a wide variety of services such as traffic management, passenger safety, as well as travel convenience and comfort. VANETs are now proposed to be part of the upcoming Fifth Generation (5G) technology, integrated with Software Defined Networking (SDN), as key enabler of 5G. The technology of fog computing in 5G turned out to be an adequate solution for faster processing in delay sensitive application, such as VANETs, being a hybrid solution between fully centralized and fully distributed networks. In this paper, we propose a three-way integration between VANETs, SDN, and 5G for a resilient VANET security design approach, which strikes a good balance between network, mobility, performance and security features. We show how such an approach can secure VANETs from different types of attacks such as Distributed Denial of Service (DDoS) targeting either the controllers or the vehicles in the network, and how to trace back the source of the attack. Our evaluation shows the capability of the proposed system to enforce different levels of real-time user-defined security, while maintaining low overhead and minimal configuration.

Recently, some papers that apply a multi-armed bandit algorithm for channel selection in a cognitive radio system have been reported. In those papers, channel selection based on Upper Confidence Bound (UCB) algorithm has been proposed. However, in those selection, secondary users are not allowed to transmit data over same channels at the same time. Moreover, they do not take security of wireless communication into account. In this paper, we propose secure channel selection methods based on UCB algorithm, taking secrecy capacity into account. In our model, secondary users can share same channel by using transmit time control or transmit power control. Our proposed methods lead to be secure against an eavesdropper compared to conventional channel selections based on only estimated channel availability. By computer simulation, we evaluate average system secrecy capacity. As a result, we show that our proposed channel selections improve average system secrecy capacity compared to conventional channel selection.

Cloud computing is a wide architecture based on diverse models for providing different services of software and hardware. Cloud computing paradigm attracts different users because of its several benefits such as high resource elasticity, expense reduction, scalability and simplicity which provide significant preserving in terms of investment and work force. However, the new approaches introduced by the cloud, related to computation outsourcing, distributed resources, multi-tenancy concept, high dynamism of the model, data warehousing and the nontransparent style of cloud increase the security and privacy concerns and makes building and handling trust among cloud service providers and consumers a critical security challenge. This paper proposes a new approach to improve security of data in cloud computing. It suggests a classification model to categorize data before being introduced into a suitable encryption system according to the category. Since data in cloud has not the same sensitivity level, encrypting it with the same algorithms can lead to a lack of security or of resources. By this method we try to optimize the resources consumption and the computation cost while ensuring data confidentiality.