Abdellah Ait Ouahman

Access control in the Internet of Things

In this paper, an extensive state of the art review of different access control solutions in IoT within the Objectives, Models, Architecture and Mechanisms (OM-AM) way is provided. An analysis of the security and privacy requirements for the most dominant IoT application domains, including Personal and home, Government and utilities, and Enterprise and industry, is conducted. The pros and cons of traditional, as well as recent access control models and protocols from an IoT perspective are highlighted. Furthermore, a qualitative and a quantitative evaluation of the most relevant IoT related-projects that represent the majority of research and commercial solutions proposed in the field of access control conducted over the recent years (2011- 2016) is achieved. Finally, potential challenges and future research directions are defined.

High Power Amplifier Pre-Distorter Based on Neural-Fuzzy Systems for OFDM Signals

In this paper, a novel High Power Amplifier (HPA) pre-distorter based on Adaptive Networks - Fuzzy Inference Systems (ANFIS) for Orthogonal Frequency Division Multiplexing (OFDM) signals is proposed and analyzed. Models of Traveling Wave Tube Amplifiers (TWTA) and Solid State Power Amplifiers (SSPA), both memoryless and with memory, have been used for evaluation of the proposed technique. After training, the ANFIS linearizes the HPA response and thus, the obtained signal is extremely similar to the original. An average Error Vector Magnitude (EVM) of 10-6 can be easily obtained with our proposal. As a consequence, the Bit Error Rate (BER) degradation is negligible showing a better performance than what can be achieved with other methods available in the literature. Moreover, the complexity of the proposed scheme is reduced.

FairAccess: a new Blockchain-based access control framework for the Internet of Things

Security and privacy are huge challenges in Internet of Things (IoT) environments, but unfortunately, the harmonization of the IoT-related standards and protocols is hardly and slowly widespread. In this paper, we propose a new framework for access control in IoT based on the blockchain technology. Our first contribution consists in providing a reference model for our proposed framework within the Objectives, Models, Architecture and Mechanism specification in IoT. In addition, we introduce FairAccess as a fully decentralized pseudonymous and privacy preserving authorization management framework that enables users to own and control their data. To implement our model, we use and adapt the blockchain into a decentralized access control manager. Unlike financial bitcoin transactions, FairAccess introduces new types of transactions that are used to grant, get, delegate, and revoke access. As a proof of concept, we establish an initial implementation with a Raspberry PI device and local blockchain. Finally, we discuss some limitations and propose further opportunities. Copyright

Reduction of Power Envelope Fluctuations in OFDM Signals by using Neural Networks

One of the main drawbacks of Orthogonal Frequency Division Multiplexing (OFDM) are the large fluctuations of its power envelope. In this letter, a novel and efficient scheme based on Multilayer Perceptron (MLP) Neural Networks (NN) is proposed. The NN synthesizes the Active Constellation Expansion - (ACE) technique which is able to drastically reduce envelope fluctuations. This is achieved with much lower complexity, faster convergence, and better performance compared to previously available methods.

Towards a Novel Privacy-Preserving Access Control Model Based on Blockchain Technology in IoT

Access control face big challenges in IoT. Unfortunately, it is hard to implement current access control standards on smart object due to its constrained nature while the introduction of powerful and trusted third party to handle access control logic could harm user privacy. In this work we show how blockchain, the promising technology behind Bitcoin, can be very attractive to face those arising challenges. We therefore propose FairAccess as a new decentralized pseudonymous and privacy preserving authorization management framework that leverages the consistency of blockchain technology to manage access control on behalf of constrained devices.

Reduction of the Envelope Fluctuations of Multi-Carrier Modulations using Adaptive Neural Fuzzy Inference Systems

In this paper, a novel scheme for reducing the envelope fluctuations in multi-carrier signals applying Adaptive Neural Fuzzy Inference Systems (ANFIS) is proposed and analyzed. Once trained with signals with very low envelope fluctuations, such as those obtained by the Active Constellation Expansion - Approximate Gradient Project (ACE-AGP) algorithm, ANFIS approximately reaches a similar reduction as with ACE-AGP for multi-carrier signals without the complexity and the large convergence time of conventional ACE-AGP. We show that our approach is less complex than other previous schemes and with better performance.

Subcarrier and Power Allocation for the Downlink of Multiuser OFDM Transmission

In this paper, a new algorithm for subcarrier and power allocation for the downlink of multiuser OFDM transmission is presented. The proposed algorithm is more stable and it offers a lower complexity and better performance than previous existing algorithms.

A robust and secure perceptual hashing system based on a quantization step analysis

Perceptual hashing is conventionally used for content identification and authentication. It has applications in database content search, watermarking and image retrieval. Most countermeasures proposed in the literature generally focus on the feature extraction stage to get robust features to authenticate the image, but few studies address the perceptual hashing security achieved by a cryptographic module. When a cryptographic module is employed [1], additional information must be sent to adjust the quantization step. In the perceptual hashing field, we believe that a perceptual hashing system must be robust, secure and generate a final perceptual hash of fixed length. This kind of system should send only the final perceptual hash to the receiver via a secure channel without sending any additional information that would increase the storage space cost and decrease the security. For all of these reasons, in this paper, we propose a theoretical analysis of full perceptual hashing systems that use a quantization module followed by a crypto-compression module. The proposed theoretical analysis is based on a study of the behavior of the extracted features in response to content-preserving/content-changing manipulations that are modeled by Gaussian noise. We then introduce a proposed perceptual hashing scheme based on this theoretical analysis. Finally, several experiments are conducted to validate our approach, by applying Gaussian noise, JPEG compression and low-pass filtering.

Perceptual Image Hashing

With the fast advancement of computer, multimedia and network technologies, the amount of multimedia information that is conveyed, broadcast or browsed via digital devices has grown exponentially. Simultaneously, digital forgery and unauthorized use have reached a significant level that makes multimedia authentication and security very challenging and demanding. The ability to detect changes in multimedia data has been very important for many applications, especially for journalistic photography, medical or artwork image databases. This has spurred interest in developing more robust algorithms and techniques to allow to check safety of exchanged multimedia data confidentiality, authenticity and integrity. Confidentiality means that the exchange between encrypted multimedia data entities, which without decryption key, is unintelligible. Confidentiality is achieved mainly through encryption schemes, either secret key or public key. Authentication is an another crucial issue of multimedia data protection, it makes possible to trace the author of the multimedia data and allow to determine if an original multimedia data content was altered in any way from the time of its recording. Integrity allows degradation detection of multimedia and helps make sure that the received multimedia data has not been modified by a third party for malicious reasons. Many attempts have been noted to secure multimedia data from illegal use by different techniques fields such as encryption field, watermarking field and perceptual image hashing field. The field of encryption is becoming very important in the present era in which information security is of the utmost concern to provide end-to-end security. Multimedia data encryption has applications in internet communication, multimedia systems, medical imaging, telemedicine, military communication, etc. Although we may use the traditional cryptosystems to encrypt multimedia data directly, it is not a good idea for two reasons. The first reason is that the multimedia data size is almost always much great. Therefore, the traditional cryptosystems need much more time to directly encrypt the multimedia data. The other problem is that the decrypted multimedia data must be equal to the original multimedia data. However, this requirement is not necessary for image/video data. Due to the characteristic of human perception, a decryptedmultimedia containing small distortion is usually acceptable. Deciding upon what level of security is needed is harder than it looks. To identify an optimal security level, the cost of the multimedia information to be protected and the cost of the protection itself are to be compared carefully. At present, many available image encryption algorithms have been proposed (Ozturk & Ibrahim, 2005; 2

Design of PM Motor Drive Course and DSP Based Robot Traction System Laboratory

This paper presents a part of North Africa/Europe collaboration results in education to develop project-oriented courses in power electronics and motor drive field. The course aims to teach Permanent Magnet motor drives close to a real world project of significant size and depth so as to be motivational, namely mobile robot project. Particular skills, student will acquire, are those relative to the detailed design and implementation of PM motor controllers in DSP based rapid prototyping environment. Simulation work is completed using graphical modeling tools in Simulink/Plecs, while real-time implementation is achieved by means of eZdspF2812 board and Simulink/TI C2000 Embedded Target tools. This flexible development environment fit the robot traction system very well and provides exactly the functionality necessary for an efficient PM motor drives teaching as demonstrated by a set of simulation and experiments.