Cross-encoding of information in independent channels

aIndependent first and second information signals (content and content) are transmitted over separate independent physical channels to a receiving location. Security is provided by encoding at least the first information by means of the second information to produce encoded signals ( N′). The encoded signals and the second signals are received from the first and second channels at the second location. The encoded first signals are decoded at the receiving location by processing with the second signals. In some embodiments, the second information signals are encoded by processing with the first information signals. In a more general case, plural channels of information are "cross-encoded" by the information in plural other channels, and the plurality may be large.