
Get quantum-generated random numbers for free

A quantum random number generator developed in Spain is at the heart of a service being offered for free over the Internet.
The Colorado University Randomness Beacon (CURBy) is broadcast free and can be used anywhere for a independent open source implementation of random numbers.
Researchers at ICFO in Barcelona, Spain, worked with spinout QuSide to developed a fast quantum random number generators that is being used the US National Institute of Standards and Technology (NIST).
This is the first random number generator service to use quantum nonlocality as a source of its numbers, and the results are certifiable and traceable to a greater extent than ever before.
The process starts by generating a pair of entangled photons inside a nonlinear crystal. The photons travel via optical fibre to separate labs at opposite ends of the hall where the polarisation of each is measured. The outcomes of these measurements are truly random. This process is repeated 250,000 times per second and NIST passes these quantum measurements to the University of Colorado Boulder which creates the random bits.
A protocol called Twine marks each set of data for the beacon with a hash, allowing any user to verify the data behind each random number. The protocol can expand to let other random number beacons join the hash graph, creating a distributed ledger of randomness that everyone contributes to but no individual controls.
Intertwining the hash chains acts as a timestamp, linking the data for the beacon together into a traceable data structure. It also provides security, allowing Twine protocol participants to immediately spot manipulation of the data.
The whole process is open source and available to the public, allowing anyone to not only check their work, but even build on the beacon to create their own random number generator.
Gautam A. Kavuri et al. Traceable random numbers from a non-local quantum advantage. Nature. Published online June 11, 2025. DOI: 10.1038/s41586-025-09054-3
