Private information retrieval (PIR) lets you retrieve an item from a database without revealing which item you accessed. This query privacy guarantee holds even if the server is malicious. Efficient PIR systems are built using FHE, and are practical today for a variety of applications.
In this talk, I’ll give a high-level overview of how PIR using FHE works, and then go in-depth on the real-world deployment challenges of PIR systems, and how we tackle them.
Samir Menon is a co-founder of Spiral Privacy, which uses FHE to enable private access to blockchain information. He previously worked at Yubico, and before that worked on PIR and libsnark as a student at Stanford.
You can privately check any Bitcoin balance at https://btc.usespiral.com/, or privately read a Wikipedia article at https://spiralwiki.com. The scheme underlying our systems is outlined in this paper: https://eprint.iacr.org/2022/368.