Random numbers are essential to modern cybersecurity, serving as the foundation of the encryption systems that protect online communications, financial transactions, and sensitive information. However, generating truly random numbers has long been a challenge because conventional computers operate through deterministic processes. Even the most advanced algorithms can only approximate randomness, leaving room for attackers to identify patterns and exploit weaknesses in encrypted systems, says The New York Times (full article available to subscribers).
Researchers at ETH Zurich have spent the past decade tackling this problem through a groundbreaking quantum physics experiment that produced what experts describe as exceptionally high-quality random numbers. Published in Nature, the study demonstrates a process known as randomness amplification, which enhances imperfect random inputs by harnessing the inherently unpredictable behavior of quantum systems.
The project relied on two superconducting qubits housed in separate cryogenic refrigerators operating at just 15 millikelvin, a temperature far colder than deep space. The qubits were linked through quantum entanglement, a state that exists only under strictly quantum conditions. This arrangement allowed the researchers to access genuine quantum randomness while minimizing interference from classical physical processes that could compromise the quality of the results.
Maintaining such conditions posed a major technical challenge. Quantum systems are highly sensitive, and even small interactions with the surrounding environment can degrade their performance. By successfully creating and preserving high-quality entanglement, the team established a reliable source of quantum-generated randomness.
During a nine-hour experiment, the researchers measured the entangled qubits 1.34 billion times. An extraction algorithm then converted 5.4 billion bits from a lower-grade random number source into 45 million bits of exceptionally strong randomness. According to experts in quantum information science, the work represents one of the most convincing demonstrations yet that quantum processes can generate randomness independent of computational assumptions.
The achievement carries significant implications for cybersecurity. Weak randomness has been linked to several major security failures, including compromised cryptographic keys and attacks on digital platforms and cryptocurrency systems. By producing randomness rooted directly in quantum physics, the ETH Zurich team has demonstrated a promising path toward stronger encryption and more secure digital infrastructure.