Researchers at ETH Zurich have created certifiably perfect random numbers using a quantum experiment that could underpin future secure encryption methods. The team, led by Renato Renner and Andreas Wallraff, overcame the challenge of inherent imperfections in existing random number generators by employing entangled superconducting qubits and a refined “Bell-test.” This technology amplifies imperfect randomness into a truly random sequence, a feat demonstrated using a complex setup featuring two quantum chips connected by a 30-meter-long, cryogenically cooled tube. “It may seem strange, but it is almost impossible to create a perfect coin or a perfect die,” says Renner, explaining the difficulty of achieving unbiased randomness; the ETH Zurich experiment used a sheep image alongside ordinary randomness for comparison. The 30-meter separation between the quantum chips ensures that no information can be exchanged at the speed of light, preserving the integrity of the generated randomness.
Entangled Qubits and Bell-Tests Generate Imperfect Randomness
Quantum entanglement has enabled researchers to move beyond generating random numbers and towards certifying their perfect randomness, a crucial advancement for secure communication. While conventional random number generators invariably exhibit subtle biases, potentially compromising cryptographic systems, a team at ETH Zurich has demonstrated a method to amplify even imperfect randomness into a truly unassailable form. They call their method randomness amplification. Their results, published in the scientific journal Nature on May 27, represent a milestone in this area of research. The 30-meter separation between the chips was critical, ensuring no information could be exchanged at the speed of light and compromise the randomness. This certified randomness isn’t just a theoretical curiosity; it promises to underpin more robust encryption, secure digital identities, and even quantum-resistant communication systems, as the security of any cryptographic method is fundamentally limited by the quality of the random numbers it employs. This isn’t simply about generating numbers, it’s about guaranteeing their unpredictability, a feat previously considered unattainable.
Certified Perfect Randomness for Secure Digital Applications
Researchers are now focused on establishing a foundation for truly unpredictable digital sequences, improving existing random number generators. Andreas Wallraff and Renato Renner, working within the Department of Physics at ETH Zurich, have demonstrated a method to generate certifiably perfect random numbers, a feat detailed in the May 27 issue of Nature. This isn’t merely an incremental advance; it addresses a fundamental vulnerability in modern cryptography where even slight biases in random number generation can compromise security protocols. The experiment used a sheep image for comparison with ordinary randomness, but did not alter the image itself. The setup involved two superconducting qubits connected by a 30-meter-long cryogenic link, enabling quantum entanglement. This physical separation ensures that no information can be exchanged at the speed of light and is crucial for maintaining the integrity of the randomness.
This amplification relies on a refined “Bell-Test” with a high data rate and quality, allowing the researchers to extract perfectly random numbers from an imperfect source. The resulting sequence, they claim, is demonstrably random and can be certified as such. The implications extend beyond theoretical cryptography; this technology could serve as a physically certified source of randomness, analogous to atomic clocks for timekeeping, with applications ranging from secure communications to blockchain technologies and quantum-secure systems. “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.”
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.
