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7,788 results on '"A. Chaoui"'

1. Secure quantum bit commtiment from separable operations

Author

Chaoui, Ziad, Pappa, Anna, and Rosati, Matteo

Subjects
Quantum Physics
Abstract

Bit commitment is a fundamental cryptographic primitive and a cornerstone for numerous two-party cryptographic protocols, including zero-knowledge proofs. However, it has been proven that unconditionally secure bit commitment, both classical and quantum, is impossible. In this work, we demonstrate that imposing a restriction on the committing party to perform only separable operations enables secure quantum bit commitment schemes. Specifically, we prove that in any perfectly hiding bit commitment protocol, an honestly-committing party limited to separable operations will be detected with high probability if they attempt to alter their commitment. To illustrate our findings, we present an example protocol.

Published
2025

2. Why quantum state verification cannot be both efficient and secure: a categorical approach

Author

Wiesner, Fabian, Chaoui, Ziad, Kessler, Diana, Pappa, Anna, and Karvonen, Martti

Subjects
Quantum Physics, Computer Science - Cryptography and Security, Mathematics - Category Theory
Abstract

The advantage of quantum protocols lies in the inherent properties of the shared quantum states. These states are sometimes provided by sources that are not trusted, and therefore need to be verified. Finding secure and efficient quantum state verification protocols remains a big challenge, and recent works illustrate trade-offs between efficiency and security for different groups of states in restricted settings. However, whether a universal trade-off exists for all quantum states and all verification strategies remains unknown. In this work, we instantiate the categorical composable cryptography framework to show a fundamental limit for quantum state verification for all cut-and-choose approaches used to verify arbitrary quantum states. Our findings show that the prevailing cut-and-choose techniques cannot lead to quantum state verification protocols that are both efficient and secure.

Published
2024

3. Removing cloud shadows from ground-based solar imagery

Author

Chaoui, Amal, Morgan, Jay Paul, Paiement, Adeline, and Aboudarham, Jean

Subjects
Computer Science - Computer Vision and Pattern Recognition, Electrical Engineering and Systems Science - Image and Video Processing
Abstract

The study and prediction of space weather entails the analysis of solar images showing structures of the Sun's atmosphere. When imaged from the Earth's ground, images may be polluted by terrestrial clouds which hinder the detection of solar structures. We propose a new method to remove cloud shadows, based on a U-Net architecture, and compare classical supervision with conditional GAN. We evaluate our method on two different imaging modalities, using both real images and a new dataset of synthetic clouds. Quantitative assessments are obtained through image quality indices (RMSE, PSNR, SSIM, and FID). We demonstrate improved results with regards to the traditional cloud removal technique and a sparse coding baseline, on different cloud types and textures.

Published
2024

21. A Program Evaluation of an International, Intercultural E-Community-Engagement Initiative

Author

Audrey F. Falk, Martina Jordaan, Sameerah T. Sae, Madasu Bhaskara Rao, and Nour El Houda Chaoui

Abstract

Purpose: This program evaluation aimed to investigate the benefits and challenges of an international, intercultural, e-community-engagement experience involving youth and higher education students. The authors sought to understand the meaning that participants would make of an international, intercultural, e-community-engagement experience. Design/methodology/approach: The program evaluation component of this project was qualitative, participatory and action-oriented. It was composed of online reflection sessions with small, international groups of higher education students from Iraq, India, Morocco, South Africa and the USA immediately following each of five interactive exchange sessions with youth from South Africa. It also included one culminating reflection session to which all of the higher education student participants were invited and a written questionnaire that was completed by the youth participants at the conclusion of the project. The reflection sessions were recorded and transcribed. Transcripts and survey data were reviewed for emergent themes. Findings: Cultural exposure emerged as the primary theme with participants valuing the opportunity to learn about different cultures and to connect with individuals from across the globe. Research limitations/implications: This program evaluation was not designed as a generalizable study. This pilot initiative provides evidence of the potential value and importance of international, intercultural e-community-engagement experiences for youth and higher education students. Practical implications: The potential value of technology to build exchange opportunities for young people is immense and largely untapped. International, intercultural e-community-engagement initiatives can be made available to students globally with relatively limited resources. A highly structured and focused plan provides clarity about expectations and requirements for students. A high level of commitment is required by all participants, including the faculty coordinators. Social implications: Although the project was brief, exposure to numerous countries and cultures allowed participants to challenge their assumptions about different peoples and places in the world. The potential benefits for greater compassion and understanding of communities and cultures in an international context are high. Originality/value: This program evaluation contributes to and extends the literature on the possibilities and challenges of international e-community-engagement; it demonstrates the potential for e-community-engagement across multiple countries to broaden students' exposure to and interest in global perspectives.

Published
2024
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32. Comprehensive Data Life Cycle Security in Cloud Computing: Current Mastery and Major Challenges

Author

Chaoui, Kenza, Kabachi, Nadia, Harbi, Nouria, Badir, Hassan, Filipe, Joaquim, Editorial Board Member, Ghosh, Ashish, Editorial Board Member, Prates, Raquel Oliveira, Editorial Board Member, Zhou, Lizhu, Editorial Board Member, Tabaa, Mohamed, editor, Badir, Hassan, editor, Bellatreche, Ladjel, editor, Boulmakoul, Azedine, editor, Lbath, Ahmed, editor, and Monteiro, Fabrice, editor

Published
2024
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