Most digital security still rests on stored secrets, and anything stored can be copied or leaked. Physical unclonable functions take a different approach, deriving keys from microscopic manufacturing differences that no two devices share. A team led by Yating Wan's Integrated Photonic Laboratory at KAUST, working with Boon Ooi's group, has pushed the idea to striking performance using chaotic vertical-cavity surface-emitting lasers roughly 200 micrometres wide.
Each laser produces a chaotic optical output whose intensity fluctuations are effectively impossible to predict or reproduce, yet carry distinctive statistical fingerprints. Varying drive current and temperature multiplies the distinct configurations, and an AI model trained on these signatures verifies whether a key genuinely came from a registered device. Testing an array of more than 100 lasers, the researchers report each device generating over 500 gigabits of data per second, enough for a fresh key roughly every 10 nanoseconds.
Each key carries more than 5,000 bits of entropy, around twenty times that of standard encryption keys, at an energy cost below one picojoule per bit. Because the lasers can be fabricated with standard mass-production processes, the approach could be integrated into compact security chips. The team's next step, described alongside the Nature Electronics paper, is a prototype that combines generation, verification and secure transmission in one package.