Mouhcine Guennoun

Youssef Gahi, Mouhcine Guennoun, Khalil El-Khatib

Cloud computing emerges as an attractive solution that can be delegated to store and process confidential data. However, several security risks are encountered with such a system as the securely encrypted data should be decrypted before processing them. Therefore, the decrypted data is susceptible to reading and alterations. As a result, processing encrypted data has been a research subject since the publication of the RSA encryption scheme in 1978. In this paper we present a relational database system based on homomorphic encryption schemes to preserve the integrity and confidentiality of the data. Our system executes SQL queries over encrypted data. We tested our system with a recently developed homomorphic scheme that enables the execution of arithmetic operations on ciphertexts. We show that the proposed system performs accurate SQL operations, yet its performance discourages a practical implementation of this system.

Youssef Gahi, Mouhcine Guennoun, Zouhair Guennoun et al.

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.

Youssef Gahi, Mouhcine Guennoun, Zouhair Guennoun et al.

The trend towards delegating data processing to a remote party raises major concerns related to privacy violations for both end-users and service providers. These concerns have attracted the attention of the research community, and several techniques have been proposed to protect against malicious parties by providing secure communication protocols. Most of the proposed techniques, however, require the involvement of a third party, and this by itself can be viewed as another security concern. These security breaches can be avoided by following a new approach that depends on data sorted, managed, and stored in encrypted form at the remote servers. To realize such an approach, the encryption cryptosystem must support algebraic operations over encrypted data. This cryptosystem can be effective in protecting data and supporting the construction of programs that can process encrypted input and produce encrypted output. In fact, the latter programs do not decrypt the input, and therefore, they can be run by an un-trusted party without revealing their data and internal states. Furthermore, such programs prove to be practical in situations where we need to outsource private computations, especially in the context of cloud computing. Homomorphic cryptosystems are perfectly aligned with these objectives as they are a strong foundation for schemes that allow a blind processing of encrypted data without the need to decrypt them. In this dissertation we rely on homomorphic encryption schemes to secure cloud computing, services and routing protocols. We design several circuits that allow for the blind processing and management of data such that malicious parties are denied access to sensitive information. We select five areas to apply our models to. These models are easily customized for many other areas. We also provide prototypes that we use to study the performance and robustness of our models.