# Certified Quantum Random Numbers from Untrusted Light

## TL;DR

This paper presents an ultrafast, secure quantum random number generator that operates at 8.05 Gb/s using an untrusted light source, with rigorous security guarantees suitable for cryptographic applications.

## Contribution

It introduces and experimentally demonstrates the fastest composably secure quantum random number generator from an untrusted source.

## Key findings

- Achieved 8.05 Gb/s random number generation rate.
- Provided a fully composable security proof.
- Demonstrated real-time operation with rigorous security parameters.

## Abstract

A remarkable aspect of quantum theory is that certain measurement outcomes are entirely unpredictable to all possible observers. Such quantum events can be harnessed to generate numbers whose randomness is asserted based upon the underlying physical processes. We formally introduce, design and experimentally demonstrate an ultrafast optical quantum random number generator that uses a totally untrusted photonic source. While considering completely general quantum attacks, we certify and generate in real-time random numbers at a rate of $8.05\,$Gb/s with a rigorous security parameter of $10^{-10}$. Our security proof is entirely composable, thereby allowing the generated randomness to be utilised for arbitrary applications in cryptography and beyond. To our knowledge, this represents the fastest composably secure source of quantum random numbers ever reported.