Julia Len

Research Abstract:

Time and again cryptographic systems have failed because theoretical designs do not consider all the threats of real-world deployment. This frequently translates into practitioners forced into implementing ad-hoc mitigations or end users having to make the correct choices about security. And very often, they don't. The end result is subtle vulnerabilities in our most important deployed cryptographic schemes. Instead, my approach is to design new cryptography for real-world systems which targets security by default. This means designing schemes and protocols that avoid ad-hoc mitigations and instead provide robust, principled defenses with strong assurance against threats in practice. My work on secure-by-default cryptography thus far has focused on two major areas: authenticated encryption and key transparency for end-to-end encrypted systems. I have introduced a new class of attacks exploiting authenticated encryption in systems, developed new theory to act as guidance in designing better encryption schemes, and designed new practical cryptographic protocols and schemes for real-world deployment.

Bio:

Julia Len is a PhD student at Cornell University advised by Thomas Ristenpart and is based in New York City at Cornell Tech. Her research interests are broadly in the areas of applied cryptography and computer security, and she is excited about designing new cryptography for real-world systems that achieve better security. Recently, she has focused on understanding vulnerabilities in our most widely used symmetric encryption schemes (and how to fix them), as well as better security for end-to-end encrypted communication systems, including key transparency. She is a recipient of the NSF Graduate Research Fellowship, and she has previously interned at Microsoft Research and Zoom Video Communications. Before coming to Cornell, Julia completed her B.S. in Computer Science at UC San Diego in 2018.