The UMBC Cyber Defense Lab presents

Self-Defending Ledgers: Automating Distributed Ledger Security Using Multi-Agent Reinforcement Learning and Game Theory

Md Tariqul Islam 'Pavel'
Assistant Professor of Cybersecurity
UMBC Department of Information Systems

12–1pm EDT, Friday, October 3, 2025 via Webex

Distributed ledger technologies (DLTs) continue to face significant security challenges. While attackers constantly adapt their strategies, governance mechanisms often remain static. Our work addresses this critical gap by introducing a framework for self-defending ledgers, where nodes enforce ledger security through adaptive governance driven by multi-agent reinforcement learning (MARL) grounded in game-theoretic principles. We model DLT consensus as a repeated Bayesian game, in which participants hold probabilistic beliefs about peer behavior, allowing agents to make strategic decisions under partial observability of adversarial actions. Our framework enables nodes to model, detect, and respond to a wide range of malicious behaviors, including bribery, selfish mining, equivocation, Sybil attacks, and collusive voting, by continuously updating Bayesian trust beliefs and governance policies based on network observations. We formally prove that networks with an honest majority reach stable equilibria and provide bounds on adversarial influence. Experiments across five major protocols show that agents effectively identify attacks with high accuracy while substantially reducing adversarial success. This work demonstrates the potential of game-theoretic MARL to provide robust, self-adaptive security in varied DLT environments, paving the way for resilient and autonomous ledger governance.

Md Tariqul Islam 'Pavel' is an assistant professor of cybersecurity in UMBC's Department of Information Systems. His research centers on the security, efficiency, and fault-tolerance of distributed computing systems, with a strong emphasis on blockchain, cloud, and vehicular networks. He develops formal models, algorithms, and protocols that address critical vulnerabilities in decentralized ecosystems, spanning inter-blockchain communication, smart contract migration, and trustworthy governance. His work combines cryptography, game theory, and system design to build scalable, resilient infrastructures. He earned his PhD and MS from the University of Kentucky and BS from the University of Dhaka, Bangladesh.

Meet Ann Tropea, the assistant director for engaged media with the Center for Democracy and Civic Life, and the full-time staff advisor for the Student Media Collective, which includes The Retriever, Bartleby, and WMBC. Ann’s academic background is in mass media communications studies and law. In her spare time, she (separately) hosts a podcast and acts as a doula, helping support families during birth.

Q: Briefly introduce yourself. What’s one essential thing you’d want another Retriever to know about you?

A: I am the assistant director for engaged media with the Center for Democracy and Civic Life and the full time staff advisor for the Student Media Collective (SMC)—the newly chartered student organization for student-run media on campus. I bring many years of professional editorial, communications, and legal expertise to my position. I am a career editor, published author, and podcast producer/co-host.

I am also a licensed attorney in Louisiana and the District of Columbia, and I have represented a variety of individual and multinational clients in both federal and state court litigation. I hold a law degree from Loyola University Chicago School of Law and graduated magna cum laude in mass media communication studies from New York University. I am also a certified doula and enjoy supporting families in their birth and reproductive journeys.

Q: Tell us about someone in the UMBC community who has inspired you or supported you, and how they did it.

A: I joined the UMBC community as a staff member in October 2023 with zero experience working in higher education. There are so many folks who have supported and inspired me from day one, but special thanks are due to Isabel Taylor (former Retriever editor-in-chief), David Hoffman (director, Center for Democracy and Civic Life), and Renique Kersh (VP for Division of Student Affairs) who all saw my potential during the interview process and allowed me to join this incredible campus community.

Q: What’s the one thing you’d want someone who hasn’t joined the UMBC community to know about the support you find here?

A: No matter who you are, or where you’re coming from, you belong at UMBC.

Q: What part of your job do you enjoy the most and why?

A: I absolutely love working with the students in all three media groups that form the SMC (The Retriever, WMBC, and Bartleby) that I advise as the primary focus of my work. They are smart, fearless, and creative—I am incredibly lucky to have such amazing student colleagues to work side-by-side with every day.

Q: What brought you to UMBC in the first place?

A: I care deeply about making the world a more just and equitable place, where everyone has the opportunity to thrive. I came to UMBC because this is a place where it was clear from day one that I share those values with each and every person on this campus.

Q: Since you’ve been a part of the UMBC community, how have you found support of your WHY?

A: I grew up in Southern California and feel like that gives me some leeway to lean a bit into the woo-woo…. UMBC is a magical place where community and collaboration are radical acts of love. It’s not just “a” why. It’s the only why.

Q: Are you involved in any campus organizations? Tell us about what you love about them!

A: I’m a new member of the Exempt Staff Senate and am thrilled to serve on the executive board as the incoming communications manager with such a dedicated (and fun!) group of folks from across the university who are dedicated to doing good work.

UMBC’s greatest strength is its people. When people meet Retrievers and hear about the passion they bring, the relationships they create, the ways they support each other, and the commitment they have to inclusive excellence, they truly get a sense of our community. That’s what “Meet a Retriever” is all about.

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