XRD: Scalable Messaging System with Cryptographic Privacy

Albert Kwon


Even as end-to-end encrypted communication becomes more popular, private messaging remains a challenging problem due to metadata leakages, such as who is communicating with whom. Most existing systems that hide communication metadata either (1) do not scale easily, (2) incur significant overheads, or (3) provide weaker guarantees than cryptographic privacy, such as differential privacy or heuristic privacy. In this talk, I will presents XRD, a metadata private messaging system that provides cryptographic privacy, while scaling easily to support more users by adding more servers. At a high level, XRD uses multiple mix networks in parallel with several techniques, including a novel technique to efficiently and privately verify the correctness of mix network operations. As a result, XRD is more than 10x faster than prior messaging systems that provide cryptographic privacy.


Albert Kwon is a sixth year student at MIT working with Srini Devadas. He is broadly interested in applied cryptography, and likes to design and implement systems that can enhance users' privacy. His most recent focus has been on anonymous and private communication systems.

Time and Place

Tuesday, January 8, 4:15pm
Gates 463A