|Title||Comments on 'Arithmetic Coding as a Non-Linear Dynamical System'|
|Publication Type||Journal Articles|
|Authors||Pande, A., J. Zambreno, and P. Mohapatra|
|Journal||Communications in Nonlinear Science and Numerical Simulation (CNSNS)|
Nagaraj et al. [1, 2] present a skewed-non-linear Generalized Luroth Series (s-nGLS) framework. S-nGLS uses non-linear maps for GLS to introduce a security parameter a which is used to build a keyspace for image or data encryption. The map introduces non-linearity to the system to add an "encryption key parameter". The skew is added to achieve optimal compression efficiency. s-nGLS used as such for joint encryption and compression is a weak candidate, as explained in this communication. First, we show how the framework is vulnerable to known plaintext based attacks and that a key of size 256 bits can be broken within 1000 trials. Next, we demonstrate that the proposed non-linearity exponentially increases the hardware complexity of design. We also discover that s-nGlS can’t be implemented as such for large bitstreams. Finally, we demonstrate how correlation of key parameter with compression performance leads to further key vulnerabilities.