Lydia of The National Institute of Standards and Technology (NIST)

In today’s digital world, distributed systems have become the invisible backbone of modern computing. A distributed system is a collection of independent computers or nodes that work together to appear as a single coherent system. These systems are designed to share resources, handle large-scale computations, ensure availability, and increase fault tolerance. From cloud computing platforms like Amazon Web Services (AWS) and Google Cloud, to peer-to-peer applications, blockchain networks used in cryptocurrencies and distributed machine-learning is a fundamental research area in AI.

Building reliable distributed systems is not trivial. Nodes may fail, networks can introduce delays or errors, and in some cases, components may behave in unexpected or even malicious ways. Ensuring consistency, availability, and fault tolerance in such environments is a major challenge. This is where the concept of Byzantine fault tolerance becomes critical.

Dr. Ouaili will focus on the Byzantine Agreement, which refers to a class of algorithms designed to help distributed systems reach consensus even when some of the nodes behave maliciously or unpredictably. This problem was first formalized as the Byzantine Generals Problem, where participants must agree on a common strategy despite the presence of traitors. In modern systems, this translates to ensure that honest nodes agree on the state of the system or a transaction, even if some components are compromised or send misleading information.

Next, Dr. Ouaili will discuss the design and deployment of Byzantine Agreement protocols. To begin, she will recall the fundamental results by Leslie Lamport, Robert Shostak, and Marshall Pease (1982), which introduced the Byzantine Generals Problem and laid the foundation for understanding consensus in unreliable and potentially malicious environments. This result has had a lasting impact on both classical distributed algorithms and modern protocols used in cloud computing and blockchain technologies.

As distributed systems today must handle millions of users, it is essential to examine how Byzantine Agreement protocols deal with scalability and performance at such a large scale. Alongside the technical analysis, we will also discuss the broader implications of these technologies for industry and society, especially in terms of security, trust, and the management of decentralized systems.

Biography:

Lydia Ouaili is a PhD student at the Conservatoire National des Arts et Métiers (CNAM) in Paris, France, where she has been conducting research since 2022. Her work focuses on distributed systems, with a particular emphasis on fault-tolerant protocols and their scalability. She is dedicated to designing efficient protocols that can support a large number of participants while remaining resilient to malicious behavior.

Before pursuing her PhD in computer science, Lydia studied mathematics. Between 2016 and 2021, she attended Aix-Marseille University in France and USTHB in Algeria, where she completed a PhD in mathematics in 2020. This period coincided with the rapid rise of artificial intelligence and computer security technologies, which inspired her to expand her expertise and transition into the field of computer science. Her decision to pursue a second doctorate marked a significant turning point, opening up new opportunities, especially in industry. Since April 2024, Lydia has been a visiting researcher at the National Institute of Standards and Technology (NIST) in the United States, working within the Connected Smart Systems Division.

In addition to her academic endeavors, Lydia is actively involved in volunteering. She has spent four years mentoring students and contributing to educational initiatives within academic organizations. Lydia has also participated in conference organization and technical support, including roles at IEEE Cloudnet 2022 and PSD 2022.