Researchers at MIT have developed a physical token, based on tiny glass spheres encased in epoxy resin, as a more secure alternative to generating cryptographic keys electronically. With computers getting ever more powerful, especially when quantum-based technology come on the scene, some predict the mathematical algorithms which underpin current encryption techniques could be broken. Such computers may be capable of factorising the product of very large prime numbers, but would struggle to unravel a one-way function based on a physical token. So the theory goes. The MIT boffins created a physical one-way function by connecting cryptography with mesoscopics, the study of how waves travel in disordered materials.