Welcome!
I am a Ph.D. candidate in Electrical and Computer Engineering at Princeton University, with an expected graduation of May 2026. I have been working with Professor Jennifer Rexford and Professor Maria Apostolaki at Princeton University to design high-performance, Internet-native systems for network security and privacy. My research lies at the intersection of software-defined networks, systems, and security, leveraging programmable data planes across hardware and software to make today’s networks safer and smarter.
My work has been recognized with competitive funding, high-profile awards, and patents. SmartCookie [USENIX Security 2024] was supported by three years of NSF GRFP funding and is currently patent-pending; Tango [NSDI 2024] received the Applied Networking Research Prize from IETF/IRTF for outstanding applied networking research; and PraxiGuard secured the Wallace Memorial Fellowship, Princeton’s highest honor for graduate engineering research excellence. In addition, my 5G work [USENIX Security 2024] with Microsoft Research is patent-pending, and my efforts have been recognized with Princeton’s Research Day Innovation & Entrepreneurial Mindset Award and the Pramod Subramanian ’17 Early Career Graduate Award.
I am currently on the academic and research job market! If my work resonates with you, I’d be glad to discuss opportunities or collaborations. Please feel free to reach out.
Research
My research develops practical systems that bring security and privacy to real-world networks—without compromising performance. Most existing solutions treat the Internet as a black box, adding protections on top that slow applications or demand tech-savvy users. In contrast, my work pushes security functions into the network itself and uses hardware–software co-design to make defenses scalable, performant, and deployable today. My research philosophy is guided by three principles:
(i) security and privacy functions should run in-network or be natively network-aware,
(ii) hardware–software co-design is essential for scalable defenses, and
(iii) cooperation among incentive-aligned actors enables deployable, collective mechanisms to protect users.
I have applied this philosophy across both the network edge and core. At the edge, my system SmartCookie (USENIX Security 2024, patent-pending) introduced a layered hardware–software defense that blocks large-scale SYN-flood attacks without degrading user performance. My work on 5G fronthaul security uncovered new integrity vulnerabilities in emerging cellular protocols, prompting calls for stronger protections. I also introduced Sieve, which generalizes SmartCookie’s layered approach to other volumetric attacks. In the network core, my system Tango (NSDI 2024, IETF/IRTF Applied Networking Research Prize) showed how cooperating edge networks can jointly discover and select safer Internet paths using only existing BGP mechanisms. Building on this, my ongoing work PraxiGuard develops a principled, network-aware model for splitting traffic across multiple paths to jointly optimize privacy and performance, mitigating website-fingerprinting attacks.
Across all efforts, I emphasize building prototypes, open-source artifacts, and deployable systems to ensure real-world impact. Taken together, my work lays the foundation for ubiquitous, deployable network security and privacy—protecting users at Internet scale.
Publications
SmartCookie: Blocking Large-Scale SYN Floods with a Split-Proxy Defense on Programmable Data Planes
Sophia Yoo, Xiaoqi Chen, Jennifer Rexford
USENIX Security 2024
Paper (PDF) · Artifact Appendix (PDF) · Slides (PDF) · Live Demo Video · P4 Code (GitHub)
On the Criticality of Integrity Protection in 5G Fronthaul Networks
Sophia Yoo*, Jiarong Xing*, Xenofon Foukas, Daehyeok Kim, Michael K. Reiter
USENIX Security 2024
Paper (PDF)
*co-first authors
TANGO: Secure Collaborative Route Control across the Public Internet
Henry Birge-Lee, Sophia Yoo, Benjamin Herber, Jennifer Rexford, Maria Apostolaki
NSDI 2024
Paper (PDF) · Slides (PDF)
Sieve: Layered Network Defenses against Large-Scale Attacks
Sophia Yoo, Satadal Sengupta, Maria Apostolaki, Jennifer Rexford
ONF P4 Workshop 2023
Paper (PDF) · Slides (PPTX)
Distributed In-Network SYN Flooding Mitigation
Sophia Yoo, Xiaoqi Chen, Jennifer Rexford
Princeton Research Day 2022 (Poster)
Poster (PDF) · Slides (PPTX) · Video · P4 Code (GitHub)
Secure Keyed Hashing on Programmable Switches
Sophia Yoo, Xiaoqi Chen
ACM SIGCOMM 2021 Workshop on Secure Programmable Network Infrastructure (SPIN 2021)
Paper (PDF) · Slides (PPTX) · Video · P4 Code (GitHub)
CV
Last updated: October 08, 2025
Out-of-Band Interests
A meaningful part of my life takes place away from the (computer) keyboard and closer to the (piano) keyboard. Music has long been one of my constants — I play violin, piano, guitar, and harp — sometimes just for fun and sometimes professionally. You can find a few candid videos on my personal YouTube channel, or see me perform with Joyful Sound of Music on our YouTube channel. In my free time, I also give music lessons at Joy Music Studio, where I enjoy working with students of all ages — from the young to the young at heart. I’m drawn to reading and deep conversation on many topics — with a recent pull toward philosophy, psychiatry, and classic Russian literature. I also love touching grass, especially with the four-pawed members of my extended family.