Interesting fact: as of today, this is powered by the most efficient and practical PIR scheme. Under the hood, there is a ciphertext compression mechanism called packing. A paper came out a month ago that optimized the packing throughput by 5x compared to the prior state of the art. It’s called ReInsPIRe. The buffer introduced by the speed up has allowed us to reduce parameters controlling decryption correctness. The security parameters stay the same. With more room for noise, we applied a number of tricks such as rounding encryption at the client/server boundaries, which reduced total bandwidth. There are also GPUs involved for the matrix-vector multiplication of the database by the client query. The results are sub 200KB total per-query bandwidth and sub 50ms server time on a 1.88 GB database. The wallet PIR databases are sharded into chunks of under 500 MB. So, in production, the server time and bandwidth are even smaller.