A Framework for Stream Ciphers Based on Pseudorandomness, Randomness and Coding

Abstract

This paper yields a generic framework for design of stream ciphers based on a joint employment of pseudo-randomness, randomness and coding, and its two particular settings called SCF-E and SCF-W: The first one is based on a simple homophonic encoding via random bits embedding; The second one employs the wire-tap channel coding. In the both schemes decoding complexities with and without secret key are extremely different providing the origin for the security. The developed frameworks have potential of providing that complexity of recovering secret key in the known plaintext attacking scenario is close to the complexity of recovering the secret key via the exhaustive search. The proposed design approach can be considered as a trade-off between the increased security and decreased communications efficiency which in a number of scenarios appears as a suitable one.