Zouhair Guennoun

Privacy Preserving Scheme for Location-Based Services

Homomorphic encryption schemes make it possible to perform arithmetic operations, like additions and multiplications, over encrypted values. This capability provides enhanced protection for data and offers new research directions, including blind data processing. Using homomorphic encryption schemes, a Location-Based Service (LBS) can process encrypted inputs to retrieve encrypted location-related information. The retrieved encrypted data can only be decrypted by the user who requested the data. The technology still faces two main challenges: the encountered processing time and the upper limit imposed on the allowed number of operations. However, the protection of users’ privacy achieved through this technology makes it attractive for more research and enhancing. In this paper we use homomorphic encryption schemes to build a fully secure system that allows users to benefit from location-based services while preserving the confidentiality and integrity of their data. Our novel system consists of search circuits that allow an executor (i.e. LBS server) to receive encrypted inputs/requests and then perform a blind search to retrieve encrypted records that match the selection criterion. A querier can send the user’s position and the service type he/she is looking for, in encrypted form, to a server and then the server would respond to the request without any knowledge of the contents of the request and the retrieved records. We further propose a prototype that improves the practicality of our system.

Wireless Mobile Evolution to 4G Network

In this paper, we give an overview of the evolution of wireless mobiles starting from the first generation which is the analogue system started in 1980’s, and passing through the 2G technologies which are all digital networks and GSM is the most popular network. 2.5G networks will introduce the packet notion on the existing 2G networks and 3G will bring the quality of service as new perspective for the 3G partnership projet 3GPP and 3GPP2. However, high demand on data speed has pushed the operators to looking for 3.5G system. 3.99G networks are defined as long-term evolution for the existing 3G network and it will be based on OFDM and MIMO technologies. 4G networks was not yet defined, but requirement is to support heterogeneous networks at 100 Mbps mobility data speed.

Best selection for operators starting LTE deployment towards voice services

For most of the operators planning to start LTE deployment, recovering the cost of this expensive network is a big challenge that cannot be achieved without ensuring the continuity of voice services. In this paper, we studied and compared the possible solutions to add voice services on an LTE network which is mainly dedicated for high-speed data transfer. We concluded, in comparison to the advantages and disadvantages of the existing approaches that the One Voice approach is the target solution to meet the needed requirement. Having the support of all the famous operators and vendors, the choice of One Voice approach as a first alternative was obvious but, for the mid-term solution or backup solution the selection of CSFB approach from many operators was not clear. We proved that VOLGA approach is better than CSFB for many reasons, using less complex and less expensive handset whilst giving more comfortable user experience compared to CSFB approach. A key lesson can be learned from the existing technologies, CDMA and GSM, where the type of handset was one of the major factors of the GSM success. So before selecting the backup alternative operators should take into consideration all the aforementioned points.

Formal verification of MPR selection algorithm in the OLSR protocol

OLSR (Optimized Link State Routing) is a proactive routing protocol dedicated to MANET networks (Mobile Ad hoc Network) for establishing paths between network nodes. The operation of this protocol is mainly based on the MPR (Multi Point Relay) selection technique in order to reduce the traffic load of the network and also to minimize the path to the destination. The purpose of this paper focuses on the modeling under the UPPAAL (a tool that implements the model-checking technology for the verification of the network protocols behavior) to verify a set of properties of the MPR selection algorithm using the statistical model checking.

A fully private video on-Demand service

Video on-Demand services and other related applications have gained the utmost attention recently due to the growth of Internet and the development of streaming protocols. However, in these systems, where privacy and confidentiality are sensitive, many security aspects must be addressed. In this paper we propose a fully private video on-demand protocol that allows clients to preserve their privacy while enquiring a video store, and enables service providers to deny access for intruders or unauthorized clients. We evaluate the performance of our new protocol and show that it achieves the set objectives.

Frequency assignment for cellular mobile systems using a hybrid Tabu search with an adaptive constraint satisfaction technique

This paper presents a new algorithm for solving the frequency assignment problem in cellular mobile systems. The proposed algorithm is based on a Taboo search starting with a sequential local search method. Instead of using a minimum number of frequencies and reusing them a maximum number of times, our algorithm assembles to maximum the frequencies while avoiding deadlock. This algorithm introduces a powerful sequential local search method to start with an initial solution respecting all constraints, and minimizing the costs of employment. This initial solution is used to construct a global solution by permutation of all frequencies of a constraint link in its frequency domain in order to obtain the smallest maximum frequency used and the overall cost of such a solution. The algorithm reduces both the search space, the order of variables and values and avoids cycles through by the use of a temporary Taboo list. Our approach has been tested on standard benchmark problems called Philadelphia benchmarks of frequency assignment problem. The results obtained are equivalent to those of current methods. Moreover, our approach shows more efficiency in terms of flexibility and autonomy.

A Multi-agent System for Resource Management in GSM Cellular Networks

This paper presents a new experience in designing and developing a multi-agent system for managing frequency resources in a Regional Access Network (RAN) in GSM system (Global System for Mobile Communications). In our approach, a group of agents are distributed in the network with each regional network overseen by a supervisor agent; i.e. combining a cooperative agent to each cell called the station agent that handles the assignment of a frequency. Within a Radio Area Network – RAN and at each step, an agent is elected by all its neighbors: The election is based on empirical rules for calculating the degree of separation of an agent, the degree of saturation and the improvement claimed by the neighbors for an assignment. The elected agent assigns the smallest frequency in the spectrum that meets all its constraints. In the case of a non permitted assignment, the agent may be served by a neighboring RAN, through a mechanism of cooperation between supervisor agents of both RANs. All RANs are handled in a localized region regardless of the operating band. Our multi-agent system has been implemented in JADE, a well-known multi-agent platform based in JAVA [4]. Experimental evaluations using standard benchmarks of frequency assignment problems show that this approach can find optimal solutions and exact solutions for some instances of these problems and the results obtained are equivalent to those of current methods using simulated annealing, constraint satisfaction/optimization techniques, or neural networks. These results show that our approach is more efficient in terms of flexibility and produces an excellent degree of optimality in terms of flexibility, autonomy and resource requirements.

Private Video Streaming Service Using Leveled Somewhat Homomorphic Encryption

In this paper we address a practical application of Van Dijk somewhat homomorphic encryption over the integers scheme. This application consists of giving a client the opportunity to choose a video to watch without letting the server or any third party know which video it is, thus preserving the privacy of the client. In a prior work we have already discussed this application using a fully homomorphic encryption scheme. Our contribution in this paper is to carefully choose the encryption parameters so that decryption can work without the need of the expensive bootstrapping mechanism. We also implemented a simulation program of the used protocol to confirm our theoretical results and give an idea of the processing time needed for streaming depending on the various parameters.

Cooperative networks: Overview of state-of-the-art and trends toward green cooperative networks

This paper gives a general overview of a cooperative network (CN), which allows single-antenna mobiles to reach some of the advantages of multi-input multi-output (MIMO) systems. The idea is that single-antenna mobiles in a multi-user scenario can share their antennas so as to create a virtual MIMO system. Several important results in this area have been reached through an important research activity. However, most of them focused on performances of a CN such as rates and outage probability, with little consideration to the energetic aspect of this technology. This paper aims to cover most of what researchers all over the scientific community have achieved regarding this technology, with special regard to energy-aware CN schemes involving other new radio technologies.

An encrypted trust-based routing protocol

The interest in trust-based routing protocols has grown with the advancements achieved in ad-hoc wireless networks. However, regardless of the many security approaches and trust metrics available, trust-based routing still faces some security challenges, especially with respect to privacy. In this paper, we propose a novel trust-based routing protocol based on a fully homomorphic encryption scheme. The new protocol allows nodes, which collaborate in a dynamic environment, to evaluate their knowledge on the trustworthiness of specific routes and securely share this knowledge.