Reda bellafqira

Dr. Reda bellafqira

orcid

Research Focus & Metrics

Academic Career Length

7Years (2020-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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Verified
Journal Article
Open access
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MLMohammed Lansari
Mohammed Lansari
RBReda bellafqira
Reda bellafqira
KKKatarzyna Kapusta
Katarzyna Kapusta
VTVincent Thouvenot
Vincent Thouvenot
OBOlivier Bettan
Olivier Bettan
GCGouenou Coatrieux
Gouenou Coatrieux
Federated learning (FL) is a technique that allows multiple participants to collaboratively train a Deep Neural Network (DNN) without the need to centralize their data. Among other advantages, it comes with privacy-preserving properties, making it attractive for application in sensitive contexts, such as health care or the military. Although the data are not explicitly exchanged, the training procedure requires sharing information about participants’ models. This makes the individual models vulnerable to theft or unauthorized distribution by malicious actors. To address the issue of ownership rights protection in the context of machine learning (ML), DNN watermarking methods have been developed during the last five years. Most existing works have focused on watermarking in a centralized manner, but only a few methods have been designed for FL and its unique constraints. In this paper, we provide an overview of recent advancements in federated learning watermarking, shedding light on the new challenges and opportunities that arise in this field.

11 February 2021 in IEEE Access
Verified
Journal Article
Open access
MPMaxime Pistono
Maxime Pistono
RBReda bellafqira
Reda bellafqira
GCGouenou Coatrieux
Gouenou Coatrieux
In this paper, we propose a secure protocol that allows processing encrypted data emitted by an IOT device with low computational capabilities. Its originality is threefold. It first relies on a new fast algorithm which makes possible the conversion of Combined Linear Congruential Generator (CLCG) encrypted IOT data into data homomorphically encrypted with the Damgard-Jurik (D-J) cryptosystem. In second, an original data packing strategy is given so as to reduce communication and computation complexity as well as process several D-J encrypted data at once by means of matrix operations. In third, we introduce a crypto-watermarking based integrity control mechanism. This one combines the lightweight hash function Quark with LSB substitution so as to offer the capability to check the integrity of CLCG encrypted data. We illustrate the deployment of our protocol, in the case an honest-but-curious or malicious third party wants to process encrypted data issued from a real connected knee prosthesis. We theoretically and experimentally demonstrate the performance of our solution. This one can nearly process 500 samples every second. Beyond, our proposal is suited to the general case of IOT.

16 June 2020 in IEEE Access
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Journal Article
Open access
RBReda bellafqira
Reda bellafqira
TLThomas E. Ludwig
Thomas E. Ludwig
DNDavid Niyitegeka
David Niyitegeka
Emmanuelle GENINEmmanuelle GENIN
Emmanuelle GENIN
GCGouenou Coatrieux
Gouenou Coatrieux
This paper proposes a new privacy-preserving framework to perform rare variant case-control association tests with information provided by two parties: a Genomic Research Unit (GRU) with sequencing data from individuals affected by a disease D (cases); a Genomic Research Center (GRC) with sequencing data from healthy individuals (controls). To identify genes with rare variants involved in D, GRU needs to compare cases against controls using association tests (genome-wide association study). The main originality of our proposal is twofold. First, it positions GRC as a proxy between GRU and the server. Doing so makes it possible to use classical cryptographic tools to securely conduct association tests with no computation complexity increase, contrarily to actual state of the art proposals which are of very high complexity being based on homomorphic encryption, for instance. In particular, we show how sensitive data confidentiality can be ensured with secret key based cryptographic hashing with no need to modify statistical algorithms. In our protocol the server simply conducts statistical analyses on partially hashed data. Secondly, we introduce a novel privacy constraint: GRU’s identity should remain unknown to the server as this knowledge can give it clues about GRU’s data (e.g., diseases and genes of interest). We exhibit how Pretty Good Privacy (PGP) can be used to solve this problem. We illustrate our protocol in the case of one rare variant association test, the Weighted-Sum Statistic (WSS) algorithm, carried out on real genetic data. This secure WSS achieves the same accuracy as its nonsecure version with no increase of complexity. Furthermore, we establish that our protocol can be extended to the different rare variant association tests available in the literature.

4 July 2025 in Applied Sciences
Verified
Journal Article
Open access
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RBReda bellafqira
Reda bellafqira
GCGouenou Coatrieux
Gouenou Coatrieux
Deep neural network (DNN) watermarking is a suitable method for protecting the ownership of deep learning (DL) models. It secretly embeds an identifier within the model, which can be retrieved by the owner to prove ownership. In this paper, we first provide a unified framework for white-box DNN watermarking schemes that encompasses current state-of-the-art methods and outlines their theoretical inter-connections. Next, we introduce DICTION, a new white-box dynamic robust watermarking scheme derived from this framework. Its main originality lies in a generative adversarial network (GAN) strategy where the watermark extraction function is a DNN trained as a GAN discriminator, while the target model acts as a GAN generator. DICTION can be viewed as a generalization of DeepSigns, which, to the best of our knowledge, is the only other dynamic white-box watermarking scheme in the literature. Experiments conducted on four benchmark models (MLP, CNN, ResNet-18, and LeNet) demonstrate that DICTION achieves a zero bit error rate (BER) while maintaining model accuracy within 0.5% of the baseline. DICTION shows superior robustness, tolerating up to 95% weight pruning compared to 80% for existing methods, and it demonstrates complete resistance to fine-tuning and overwriting attacks where competing methods fail, with a BER of >0.3.

Verified
Journal Article
Open access
PDF file
THTamara El Hajjar
Tamara El Hajjar
MLMohammed Lansari
Mohammed Lansari
RBReda bellafqira
Reda bellafqira
GCGouenou Coatrieux
Gouenou Coatrieux
KKKatarzyna Kapusta
Katarzyna Kapusta
KKKassem Kallas
Kassem Kallas
Due to their considerable costs, deep neural networks (DNNs) are valuable assets that need to be protected in terms of intellectual property (IP). From this statement, DNN watermarking gains significant interest since it allows DNN owners to prove their ownership. Various methods that embed ownership information in the model behavior have been proposed. They need to fill several requirements, among them the security, which represents an attacker’s difficulty in breaking the watermarking scheme. There is also the robustness requirement, which quantifies the resistance against watermark removal techniques. The problem is that the proposed methods generally fail to meet these necessary standards. This paper presents RoSe-Mix, a robust and secure deep neural network watermarking technique designed for black-box settings. It addresses limitations in existing DNN watermarking approaches by integrating key features from two established methods: RoSe, which uses cryptographic hashing to ensure security, and Mixer, which employs image Mixup to enhance robustness. Experimental results demonstrate that RoSe-Mix achieves security across various architectures and datasets with a robustness to removal attacks exceeding 99%.

29 January 2023
Verified
Book Chapter
Closed access
PDF file
RBReda bellafqira
Reda bellafqira
MAMusab Al-Ghadi
Musab Al-Ghadi
Emmanuelle GENINEmmanuelle GENIN
Emmanuelle GENIN
GCGouenou Coatrieux
Gouenou Coatrieux