Private Information Retrieval

Retrieval without disclosure.

Notes on private information retrieval, lattice cryptography, and protocols that forget what you asked for.

index requested
records read by server0 / 64
bits learned by server0

Click any record to query it

Writing

Why every PIR scheme has to touch every record

A server that skips a row has already told you something. Working through the lower bound from first principles, and why it shapes every practical design.

Foundations
3 min

SimplePIR, and what a preprocessed hint really costs

Throughput looks excellent until you account for the client-side state. Measuring where the hint stops being worth it.

LWE
3 min

Noise growth in RLWE is a budget you spend once

Every homomorphic operation draws down the same account. A practical way to reason about depth before you write any code.

RLWE
3 min

About

I build and break PIR (Private Information Retrieval) protocols. Most of my time goes to cryptography and procrastination.

This site is where I walk through papers in public and share my thoughts. Posts tend to be long, include the arithmetic and code. I will also share my learning experiences in CTFs, embedded systems, and other areas of interest. I hope you find something useful here.

Corrections are welcome and get credited.