Hi all - saw this in New Scientist and thought you might be interested (I guess it's more stenography than cryptography): ========== "Secret signals hidden in chaos ...John Hogan of the Engineering Mathematics department at Bristol showed the BA how such unpredictable systems can be used to protect sensitive information. His team mixed the information with chaotic electrical signals, transmitted the result, and then extracted the hidden message. Hogan and his team modified simple electrical circuits to generate unpredictable signals and hid within them a recording of "Land of Hope and Glory". When the two identical circuits are connected, said Hogan, the outputs instantly synchronise so that anything added to the transmission stands out. "It's like magic." he said. If anyone intercepted the signal and fed it through a loudspeaker all they would hear is a loud hiss. This makes the system suitable for hiding confidential information - once, that is, the system is perfected. At present, a decoded message sounds like a scratchy 78 recording although it is still recognisable, said Hogan. So far the researchers have succeeded only when the two circuits are connected by wire a few cm long. They are now trying to replicate the results in circuits that are seperated by long distances and connected by a radio link. They also want to see if it can be modified for use with digital equipment." ============ Sherry ps I wonder how close to real noise the "hiss" is.