Why in news?
Researchers from India’s Raman Research Institute (RRI), the Indian Institute of Science and the University of Calgary announced a novel method for generating certified random numbers using a single quantum bit. Their study, published in October 2025, demonstrates how existing cloud‑based quantum computers can produce secure random bits without complex entanglement setups.
Understanding quantum randomness
Random numbers are essential in cryptography, simulations and secure communications. Classical processes like rolling a die can be biased, whereas quantum processes are inherently random. Traditionally, device‑independent quantum random number generation (QRNG) relied on entangled particles separated in space to ensure unpredictability. Such experiments are costly and require specialised laboratories.
What the new method achieves
- Temporal correlations: Instead of spatially separated entangled pairs, the researchers used time‑separated measurements on a single qubit. By violating the Leggett–Garg inequality—which tests whether a system’s behaviour can be explained classically—the protocol certifies randomness.
- Cloud accessibility: The team implemented the protocol on IBM’s cloud quantum computers, demonstrating that ordinary users can generate nearly one million certified random bits without owning hardware.
- Error mitigation: Special techniques were employed to reduce noise and improve the fidelity of measurements, making the results trustworthy.
- Semi‑device‑independent security: The protocol does not fully trust the devices but still offers strong guarantees. It represents a middle ground between fully device‑dependent and device‑independent schemes.
Implications
The ability to produce certified randomness on commercial quantum computers could revolutionise cybersecurity by providing stronger encryption keys. It also opens avenues for hardware certification and secure communications without needing expensive lab setups. As quantum hardware improves, such protocols may become a standard tool for governments and industries.