# Real-Time Source Independent Quantum Random Number Generator with Squeezed States

## TL;DR

This paper presents a real-time, source independent quantum random number generator using squeezed light, capable of generating secure, unpredictable random bits with high speed, suitable for cryptographic and simulation applications.

## Contribution

It introduces a self-testing QRNG that operates independently of the source, using squeezed states and homodyne detection to ensure security and real-time performance.

## Key findings

- Achieved 8.2 kb/s bit rate with squeezed states
- Compared performance with thermal states, showing improved speed
- Demonstrated security bounds using entropic uncertainty relations

## Abstract

Random numbers are a fundamental ingredient for many applications including simulation, modelling and cryptography. Sound random numbers should be independent and uniformly distributed. Moreover, for cryptographic applications they should also be unpredictable. We demonstrate a real-time self-testing source independent quantum random number generator (QRNG) that uses squeezed light as source. We generate secure random numbers by measuring the quadratures of the electromagnetic field without making any assumptions on the source; only the detection device is trusted. We use a homodyne detection to alternatively measure the Q and P conjugate quadratures of our source. Using the entropic uncertainty relation, measurements on P allow us to estimate a bound on the min-entropy of Q conditioned on any classical or quantum side information that a malicious eavesdropper may detain. This bound gives the minimum number of secure bits we can extract from the Q measurement. We discuss the performance of different estimators for this bound. We operate this QRNG with a squeezed state and we compare its performance with a QRNG using thermal states. The real-time bit rate was 8.2 kb/s when using the squeezed source and between 5.2-7.2 kb/s when the thermal state source was used.