This is the accepted version of the paper.This version of the publication may differ from the final published version. Permanent

This is the accepted version of the paper.This version of the publication may differ from the final published version. Abstract-Android smartphones are gaining big market share due to several reasons, including open architecture and popularity of its application programming interfaces (APIs) in developer community. In general, smartphone has become pervasive due to its cost effectiveness, ease of use and availability of office applications, Internet, games, vehicle guidance using locationbased services apart from conventional voice calls, messaging and multimedia services. Permanent

This is the accepted version of the paper.This version of the publication may differ from the final published version. Permanent AbstractCloud computing offers scalable on-demand services toconsumers with greater flexibility and lesser infrastructure investment. Since Cloud services are delivered using classical network protocols and formats over the Internet, implicit vulnerabilities existent in these protocols as well as threats introduced by newer architectures raise many securityand privacy concerns. In this paper, we survey factors affecting Cloud computing adoption, vulnerabilities,and attacks, and identify relevant solution directives to strengthen security and privacyin Cloud environment.

This is the accepted version of the paper.This version of the publication may differ from the final published version. Abstract-In this work, an Intrusion Detection System (IDS) for vehicular ad hoc networks (VANETs) is proposed and evaluated. The IDS is evaluated by simulation in presence of rogue nodes that can launch different attacks. The proposed IDS is capable of detecting a false information attack using statistical techniques effectively and can also detect other types of attacks. First, the theory and implementation of the VANET model that is used to train the IDS is discussed. Then an extensive simulation and analysis of our model under different traffic conditions is conducted to identify the effects of these parameters in VANETs. In addition, the extensive data gathered in the simulations is presented using graphical and statistical techniques. Moreover, rogue nodes are introduced in the network and an algorithm is presented to detect these rogue nodes. Finally, we evaluate our system and observe that the proposed application layer IDS based on cooperative information exchange mechanism is better for dynamic and fast moving networks such as VANETs as compared to other techniques available. Permanent repository link

The Internet of Things (IoT) has penetrated deeply into our lives and the number of IoT devices per person is expected to increase substantially over the next few years. Due to the characteristics of IoT devices (i.e., low power and low battery), usage of these devices in critical applications requires sophisticated security measures. Researchers from academia and industry now increasingly exploit the concept of blockchains to achieve security in IoT applications. The basic idea of the blockchain is that the data generated by users or devices in the past are verified for correctness and cannot be tampered once it is updated on the blockchain. Even though the blockchain supports integrity and non-repudiation to some extent, confidentiality and privacy of the data or the devices are not preserved. The content of the data can be seen by anyone in the network for verification and mining purposes. In order to address these privacy issues, we propose a new privacy-preserving blockchain architecture for IoT applications based on attribute-based encryption (ABE) techniques. Security, privacy, and numerical analyses are presented to validate the proposed model.

This is the accepted version of the paper.This version of the publication may differ from the final published version.Permanent repository link: http://openaccess.city.ac.uk/17316/ Link to published version: http://dx. AbstractThe extensive use of smartphones has been a major driving force behind a drastic increase of malware attacks. Covert techniques used by the malware make them hard to detect with signature based methods. In this paper, we present PIndroid-a novel Permissions and Intents based framework for identifying Android malware apps. To the best of our knowledge, PIndroid is the first solution that uses a combination of permissions and intents supplemented with Ensemble methods for accurate malware detection. The proposed approach, when applied to 1,745 real world applications, provides 99.8% accuracy (which is best reported to date). Empirical results suggest that the proposed framework is effective in detection of malware apps.

This is the accepted version of the paper.This version of the publication may differ from the final published version. Abstract-Emerging cloud computing infrastructure replaces traditional outsourcing techniques and provides flexible services to clients at different locations via Internet. This leads to the requirement for data classification to be performed by potentially untrusted servers in the cloud. Within this context, classifier built by the server can be utilized by clients in order to classify their own data samples over the cloud. In this paper, we study a privacy-preserving (PP) data classification technique where the server is unable to learn any knowledge about clients' input data samples while the server side classifier is also kept secret from the clients during the classification process. More specifically, to the best of our knowledge, we propose the first known client-server data classification protocol using support vector machine. The proposed protocol performs PP classification for both two-class and multi-class problems. The protocol exploits properties of Pailler homomorphic encryption and secure two-party computation. At the core of our protocol lies an efficient, novel protocol for securely obtaining the sign of Pailler encrypted numbers. Permanent repository link

Abstract. Cloud computing with its inherent advantages draws attention for business critical applications, but concurrently expects high level of trust in cloud service providers. Reputation-based trust is emerging as a good choice to model trust of cloud service providers based on available evidence. Many existing reputation based systems either ignore or give less importance to uncertainty linked with the evidence. In this paper, we propose an uncertainty model and define our approach to compute opinion for cloud service providers. Using subjective logic operators along with the computed opinion values, we propose mechanisms to calculate the reputation of cloud service providers. We evaluate and compare our proposed model with existing reputation models.Keywords: Cloud, Trust, Reputation, SLA, Subjective logic. IntroductionCloud computing has been recognised as an important new paradigm to support small and medium size businesses and general IT applications. The advantages of Cloud computing are multifold including better use and sharing of IT resources, unlimited scalability and flexibility, high level of automation, reduction of computer and software costs, and access to several services. However, despite the advantages and rapid growth of Cloud computing, it brings several security, privacy and trust issues that need immediate action. Trust is an important concept for cloud computing given the need for consumers in the cloud to select cost effective, trustworthy, and less risky services [2]. The issue of trust is also important for service providers to decide on the infrastructure provider that can comply with their needs, and to verify if the infrastructure providers maintain their agreements during service deployment. The work presented in this paper is being developed under the FP7 EU-funded project called OPTIMIS [5][13] to support organisations to externalise services and applications to trustworthy cloud providers. More specifically, the project focuses on service and infrastructure providers. One of the main goals of OPTIMIS is to develop a toolkit to assist cloud service providers to supply optimised services based on four different aspects, namely trust, risk, eco-efficiency, and cost. As part of the overall goal in OPTIMIS, this paper, describes a trust model to support service providers (SP) to verify trustworthiness of infrastructure providers (IP) during deployment and operational phases of the services supplied by the service providers.