ETH Zurich creates first certified perfect random numbers

ETH Zurich Generates First Certified Perfect Random Numbers Using Quantum Entanglement

Researchers at ETH Zurich have for the first time produced certifiably perfect random numbers using a quantum experiment, a result published Wednesday in the journal Nature that could reshape how digital encryption and security systems source their randomness.ethz

Amplifying Imperfection Into Perfection

The team, led by physicists Renato Renner and Andreas Wallraff, developed a method they call “randomness amplification” — a technique that takes imperfect random numbers and purifies them into provably unbiased output using the peculiarities of quantum mechanics.phys

Their setup relies on two superconducting quantum chips cooled to near absolute zero, connected by a 30-meter tube through which microwave photons travel to create quantum entanglement between the chips. The 30-meter separation is critical: it ensures that during measurement, no information can pass between the two qubits even at the speed of light, preserving the integrity of the randomness.ethz

An imperfect random number generator determines the type of measurement performed on each qubit. A specialized algorithm then amplifies the randomness of the resulting data. “The resulting sequence of zeros and ones is now really perfectly random, and we can even certify that,” Renner said in an ETH Zurich press release.phys

A Lasting Standard for Digital Security

Renner compared the achievement to “crossing a ridge,” noting that “the technical improvements allowed us, for the first time, to create random numbers that will remain perfectly random for all eternity — no matter what analytical methods are used to assess their randomness”.phys

The researchers envision the technology filling a role analogous to what atomic clocks provide for timekeeping: a physically certified source of randomness that other systems can trust. Applications could span encrypted communications, digital identity verification, public randomness services for lotteries and blockchain, and quantum-secure communication networks.ethz

Building on a Wave of Quantum Randomness Research

The ETH Zurich result arrives roughly a year after a separate team from JPMorgan Chase, Quantinuum, and several U.S. national laboratories demonstrated certified randomness expansion using a 56-qubit trapped-ion quantum computer, generating over 71,000 certified random bits verified by exascale supercomputers. The ETH approach differs in a fundamental way: rather than expanding randomness, it amplifies imperfect randomness into perfect output through a Bell test — a well-established method for confirming quantum entanglement — without relying on assumptions about the devices used.substack

“Even the strongest cryptographic methods are only as secure as the random numbers on which they are based,” the ETH Zurich team noted. “The better the randomness, the more robust the encryption — if it is weak, the entire system becomes vulnerable”.ethz