In 1999, in a conference room in Fairfax, Virginia, a young doctoral student stepped up to a podium to talk about something few people outside computer science circles had ever heard of: role-based access control systems. The internet was still a frontier. Cybersecurity was more concept than industry. And Gail-Joon Ahn, then a doctoral student at George Mason University, was presenting his first paper at a conference hosted by the Association for Computing Machinery, or ACM.
It was his first real taste of the ACM, one of the world’s largest computing societies, a global network of more than 100,000 researchers, engineers and technologists. For Ahn, it felt like stepping onto a world stage.
Nearly three decades later, that same organization has named him one of its newest fellows.
In January, ACM announced its 2025 class of fellows, selecting 71 professionals from 14 countries. Fellows represent the top 1% of ACM’s membership, recognized by their peers for remarkable results and technical leadership. The honor is one of the most prestigious distinctions in computing and is a signal that a researcher’s work has fundamentally shaped the field.
Today, Ahn is a professor of computer science and engineering in the School of Computing and Augmented Intelligence, part of the Ira A. Fulton Schools of Engineering at Arizona State University. The ACM recognition reflects his pioneering work in helping build both the underlying theory and the real-world tools that keep information secure, from designing smarter ways to control who can access sensitive data to creating practical frameworks that organizations use to defend against cyber threats.
For someone who has been an ACM member for more than 20 years, fellowship carries special weight.
“I am honored and humbled to now be an ACM Fellow,” Ahn says. “I have a debt to maintain the culture and share knowledge with the next generation.”
Recruited by a pioneer
Ahn’s path to ASU traces back to another computing heavyweight: Stephen Yau, a Fulton Schools professor of computer science and engineering, a luminary in distributed and parallel computing and a longtime architect of ASU’s computer science program.
The two first met while Ahn was completing his doctoral degree. The pair reconnected later, when Ahn was founding research director of the Digital Identity and Cyber Defense Research Center at the University of North Carolina at Charlotte. Yau attended one of Ahn’s presentations during a National Science Foundation panel review and took notice.
“I was impressed by the discussion and thought he would make a great addition to our cybersecurity team. So, I convinced him to apply,” Yau says.
At the time, ASU was building out its cybersecurity capabilities. Yau, who had founded the Information Assurance Center, one of the university’s first cybersecurity research initiatives, in 2006, understood that protecting digital infrastructure would soon be as critical as building it.
Ahn joined ASU in 2008. Over the years, he expanded and reimagined the university’s cybersecurity efforts, eventually founding what is now the Center for Cybersecurity and Trusted Foundations and the Security Engineering for Future Computing Laboratory. Under his leadership, ASU’s cybersecurity research enterprise grew into a nationally recognized program.
Building the architecture of trust
If cybersecurity has an invisible backbone, Ahn helped design parts of it.
“Gail’s technical and professional accomplishments in cybersecurity are second to none,” says Bhavani Thuraisingham, a cybersecurity research colleague and the Louis A. Beecherl Jr. Distinguished Professor of computer science at the University of Texas at Dallas. “His pioneering early work on novel access control models paved the way for securing more recent technologies such as the cloud and Internet of Things. His more recent leadership on security governance has had a tremendous impact on industry.”
Ahn’s research spans security analytics, big data-driven threat intelligence, vulnerability and risk management, identity and privacy systems and formal security models. He has authored more than 250 research papers and helped shape the policies and architectures that govern how users access distributed systems — the kinds of frameworks that determine who gets into what system and why.
In the early 2000s, as cyberattacks escalated and digital systems became entangled with power grids, finance and public safety, Ahn’s work focused on making security scalable. How do you protect systems that are no longer centralized? How do you design access control models that work across cloud platforms, mobile devices and sprawling enterprise networks?
His answers have influenced both theory and practice. He has earned the U.S. Department of Energy Early Career Principal Investigator Award and the Educator of the Year Award from the Federal Information Systems Security Educators’ Association. In 2023, he was named a fellow of the Institute of Electrical and Electronics Engineers, or IEEE. In 2024, he also received the ACM SIGSAC Outstanding Contributions Award for his leadership in the cybersecurity community.
Ross Maciejewski, director of the School of Computing and Augmented Intelligence, says Ahn’s impact extends well beyond his publication record.
“Gail has fundamentally influenced how we think about computer security — not just at ASU, but across the broader research community,” Maciejewski says. “He builds programs, mentors scholars and creates the structures that allow others to innovate. That kind of leadership amplifies his technical contributions.”
Collaboration over competition
Despite the accolades, Ahn’s philosophy is strikingly communal.
“We often feel we need competition to be successful,” he says. “But collaboration is essential if we want to solve big-picture issues in technology and beyond.”
That mindset echoes back to his earliest days with ACM — the conferences, the committees, the late-night debates about emerging threats. In the wake of global cyber crises and rapidly evolving technologies, security has become a team sport. No single lab or company can solve it alone.
As ACM prepares to formally recognize its new fellows in June in San Francisco, Ahn sees the honor not as a capstone, but as a responsibility.
The student who once nervously presented his first paper in Fairfax now stands among the field’s most established voices. The threats are bigger, the systems are more complex, and the stakes are higher.
And the work of preparing the next generation of cybersecurity leaders, he insists, is far from finished.
