Bubbling Water May Be the Cheapest Source of Truly Random Numbers
Random numbers protect your bank login — and this could make them far cheaper.
Researchers Nirjhar Debnath, Dwaipayan Datta and Kousik Dasgupta have published a new method for making random numbers out of something surprisingly ordinary: light passing through bubbling, turbulent water. Their system, nicknamed RLITBW, shines a beam through a tank of churning water full of rising bubbles. The bubbles bend and scatter the light in a way that can't be predicted, and a sensor on the other side captures that scrambled pattern as a stream of unpredictable numbers.
Why does anyone care about random numbers? Because they are the invisible skeleton key of digital life. Every time you log into your bank, send an encrypted message, or your phone scrambles data on a public Wi-Fi network, the security depends on numbers that nobody — not even a supercomputer — can guess in advance. Most "random" numbers your devices use aren't truly random at all. They come from a formula, which means anyone who figures out the starting point can predict the whole sequence. Genuine randomness usually requires expensive quantum devices or fussy, precisely tuned electronics.
Water and light, by contrast, are cheap and everywhere. The team checked their output against the NIST SP 800-22 suite — a widely used battery of tests that catches fake or patterned randomness — and it passed. They also plugged the numbers into trial-and-error optimization programs, the kind used to find the best route or schedule, and it worked as a drop-in replacement for standard generators. A 25-page paper lays out the fluid physics, the math, and the software pipeline that cleans up the raw signal.
The catch: this is a laboratory demonstration, not a product. A bubbling water tank is not something you'll find inside a phone or a laptop. Before it reaches the real world, the team would need to show the setup stays reliable over time — water gets dirty, bubbles change with temperature, and hardware needs maintenance. They'd also need to prove it can churn out numbers fast enough and cheaply enough to beat the existing chip-based alternatives.
- Random numbers are the secret ingredient behind encryption, passwords and secure online banking — and most of them today are generated by predictable formulas, not true chance.
- The new setup uses a tank of bubbling water and a light sensor instead of expensive quantum hardware, and its output passed the NIST SP 800-22 standard randomness tests.
- It's still a lab experiment: nobody has shown it works reliably outside a controlled tank, or that it's fast and cheap enough to replace the chips already inside your devices.
Why It Matters
Cheaper, trustworthy randomness means stronger everyday security for banking, messaging and personal data — without exotic hardware.