Order out of chaos

Hiding a message within a chaotic transmission is said to offer a way of securing information exchange – provided the message can be distinguished from the chaos by the receiver. Two years ago, the OCCULT European research project showed that messages could be sent at gigabit data rates over 100km of standard fibre optic cable using a chaotic mix of light frequencies with massive variation in amplitudes. Although the message was received with low bit error rates, anyone tapping into the fibre optic cable would have been unable to distinguish it from the chaotic light ‘noise’ that surrounded it. Now, in a follow on project called PICASSO (Photonic Integrated Components Applied to Secure chaoS encoded Optical communications systems), researchers are designing and testing two integrated and stable chaotic sources. In effect, these are the first prototypes for a kit that will allow chaotic transmissions to be used as a standard security measure by organisations, such as banks and governments. They are also researching techniques that will enable chaotic transmissions to be made and received at tens of gigabits per second.