Encryption Properties of Arithmetic Codes
Original Publication Date: 1981-Apr-01
Included in the Prior Art Database: 2005-Feb-11
This invention relates to a method for encrypting a bit stream from binary coded sources by recursively encoding the bits according to the Rissanen/Langdon FIFO arithmetic compression algorithm. The compression aspects of this algorithm are described, for example, in the IBM Technical Disclosure Bulletin Vol. 22, March 1980, at pages 4688-4689. The encryption method uses a key formed from the initial encoder state, a permutation of the initial state element bits, and alteration of the skew number as a function of the key itself and the past code history.