Secure high-speed quantum random number generator

A team of researchers, led by Tobias Gehring from the Technical University of Denmark and the CiViQ's project, has developed a secure high-speed quantum random number generator. The research, made in collaboration with the University of Sheffield, University of York and the Danish company Cryptomathic A/S, has recently been published in the journal Nature Communications.

A burning platform

Realizing that random numbers are the very backbone of encryption, cybersecurity, and ultimately our trust in a digitized society immediately provides another perspective on the business case. It may also make you more anxious about when ‘random’ is actually random enough to keep your personal information and bank transactions secure. Not just now, but also in the future. “Computing power keeps increasing at an exponential pace and quantum computers, capable of shattering current cryptographic schemes, are lurking around the corner. This makes the generation of true and quantum-secure random numbers one of the key challenges for a future secure communication infrastructure”, says Ulrik Lund Andersen, leader of the DNRF centre bigQ at DTU Physics.

A QRNG device which is secure even against attacks exploiting the full potential of future quantum technologies.

Extracting quantum randomness

The randomness comes in many flavours and most random number generators (RNG) are actually predictable deep down because they rely on algorithms designed to produce randomness. When looked at in the right way, the determinism of the algorithm will reveal itself in the numbers, disclosing a predictable pattern. For that reason, such devices are termed pseudo RNGs. In many applications, they are a suitable trade-off between cost and quality. For other applications, however, they are far from sufficient. If an RNG is compromised, the secret information may become public with disastrous consequences.

Quantum random number generators (QRNG) are fundamentally different. They directly tap into the probabilistic nature of quantum mechanics and the randomness is routed in hardware rather than algorithms. Quantum measurements yield inherently random outcomes and there is no way, even in principle, the outcome can be predicted. In other words, it is the ultimate randomness engine. However, noise from the measurement device overlays the pure quantum mechanical randomness and provides a peephole for hackers to gain partial, but potentially devastating, information about the sourced encryption keys. The information leakage can be estimated, and countermeasures exist for regaining security. But the efficiency depends critically on assumptions about what technology powers the hacker is in possession of.

Quantum-secure and fast

Not only does the demonstrated QRNG have the highest security against quantum attacks, but it also boosts a 2.9 Gbit/s rate, placing it firmly among the fastest QRNG devices to date. High-speed random number generation is important for applications such as quantum key distribution, which provides encryption keys secure against attacks making use of quantum computers. High speed is also important in the cloud where the heavy data traffic consumes cryptographic keys at a very high rate.

QRNG technologies usually assume that hackers don’t have access to quantum computers or other quantum technologies; we have now closed that security gap

Tobias Gehring / Technical University of Denmark

Commercializing a QRNG device

The ambitions of the team behind this quantum breakthrough go beyond research, and the clear goal is to commercialize the QRNG device so that customers worldwide can benefit from its high-speed and future-proof random numbers in a multitude of applications.

"We will have a prototype ready for testing with potential customers in the next couple of months. We are confident in the technology and its potential and at the moment we are searching for a cofounder bringing in commercial expertise", says Dino Solar Nikolic, who drives the commercialization process towards forming a spin-out company.

More information

• Read the article: Gehring, T., Lupo, C., Kordts, A. et al. Homodyne-based quantum random number generator at 2.9 Gbps secure against quantum side-information. Nat Commun 12, 605 (2021). https://doi.org/10.1038/s41467-020-20813-w

This press release was published originally at DTU Newsroom.