Quantum encryption. Computer artwork of keys embedded within a set of cubes. This could represent the concept of quantum encryption. Quantum encryption involves sending data by way of photons, the smallest unit of light. The photons are polarized, or oriented, in one of four different directions. The orientation of these photons changes as soon as they are read. Any attempts at eavesdropping or unauthorised access to the data are thwarted owing to the extreme sensitivity of the photons. Since the encrypted data can only be read by the intended recipient, quantum encryption offers, in theory, a fool-proof method of data security.