Past research in the field of cryptography has not given much consideration to arithmetic coding as a feasible encryption tech

Past research in the field of cryptography has not given much consideration to arithmetic coding as a feasible encryption technique. Over the past few years, while arithmetic coding has still been the focus of a lot of intense research, studies have proven compression-specific arithmetic coding to be largely unsuitable for encryption. This is in spite of the large size of the model that arithmetic coding works with. Adaptive modelling, in particular, offers a huge model, variable in structure, and as completely as possible a function of the entire text that has been transmitted since the time the model was initialized. This serves as a huge key, which can make decryption arbitrarily difficult. But the scheme has been shown to be vulnerable to organized cryptanalysis. The focus of the work presented in this paper has been to incorporate the results of chaos theory into arithmetic coding, to device a convenient method to make the structure of the model unpredictable and variable in nature, and yet to retain, as far as is possible, statistical harmony, so that compression is possible. A chaosbased adaptive arithmetic coding-encryption technique has been designed, developed and tested and its implementation has been discussed. For typical text files, the proposed encoder gives compression between 67.5 and 70.5 % and is not susceptible to previously carried out attacks on arithmetic coding algorithms.