Secure arithmetic coding

Although arithmetic coding offers extremely high coding efficiency, it provides little or no security as traditionally implemented. We present a modified scheme that offers both encryption and compression. The system utilizes an arithmetic coder in which the overall length within the range [0,1) allocated to each symbol is preserved, but the traditional assumption that a single contiguous interval is used for each symbol is removed. Additionally, a series of permutations are applied at the input and the output of the encoder. The overall system provides simultaneous encryption and compression, with negligible coding efficiency penalty relative to a traditional arithmetic coder.