# Speaker: Dr. Christina Garman (Purdue University)

# Title: Bento: Safely Bringing Network Function Virtualization to Tor

# Abstract: Tor is a powerful and important tool for providing anonymity and censorship resistance to users around the world. Yet it is surprisingly difficult to deploy new services in Tor—it is largely relegated to proxies and hidden services—or to nimbly react to new forms of attack. Conversely, “non-anonymous” Internet services are thriving like never before because of recent advances in programmable networks, such as Network Function Virtualization (NFV) which provides programmable in-network middleboxes. In this talk, I will present recent work which seeks to close this gap by introducing programmable middleboxes into the Tor network. In this architecture, users can install and run sophisticated “functions” on willing Tor routers. I will discuss a wide range of functions that improve anonymity, resilience to attack, performance of hidden services, and more. And I will present the design and implementation of an architecture, Bento, that protects middlebox nodes from the functions they run—and protects the functions from the middleboxes they run on. Bento does not require modifications to Tor, and we evaluate it by running it on the live Tor network. I will show that, with just a few lines of Python, we can significantly extend the capabilities of Tor to meet users’ anonymity needs and nimbly react to new threats.


# Bio: Christina Garman is an assistant professor in the Department of Computer Science at Purdue University. Her research interests focus largely on practical and applied cryptography, namely the design and analysis of real world cryptographic systems. She aims to make it easier to design and securely deploy new and complex cryptographic systems while preventing insecurities from occurring in such systems. As part of this, her work thus far has been on both building and deploying secure cryptographic systems, as well as analyzing existing systems. This includes past work on cryptographic automation and building “keyless CDNs”, as well as exploring the weaknesses of RC4 in TLS and discovering flaws in Apple’s iMessage, and her current work focusing on removing the “human element” from the deployment and analysis of cryptographic systems through the use of cryptographic automation and the development of tools. She received an NSF CAREER Award in 2021, and her work has received a best paper award at ACM CCS and been featured in numerous media, including The Washington Post, The New York Times, Wired, and The Economist. She is also one of the co-founders of Zcash, a privacy preserving cryptocurrency based on her work on Zerocash. She received her MS and Ph.D. from Johns Hopkins University in Computer Science in 2013 and 2017 respectively, and a BS in Computer Science Engineering and a BA Mathematics, with a minor in Physics, from Bucknell University in 2011.