Security Provisions in Stream Ciphers Through Self Shrinking and Alternating Step Generator

Abstract

in cryptography stream ciphers used to encrypt plain text data bits one by one. The security of stream ciphers depend upon randomness of key stream, good linear span and low probability of finding the initial states of pseudorandom generators. In this paper we propose a new stream cipher model use Feed back with carry shift registers (FCSRs) as building blocks which are considered as a source of long pseudorandom generator. Proposed model is the combined structure of alternating step generator and self shrinking generators which are commonly used stream ciphers generators. In this research we compare proposed generator against self shrinking generator (SSG), Alternating step generator (ASG) and alternating step self shrinking generator (ASSG) and we concludes that proposed generator architecture is best for encryption because it satisfies all necessary conditions of a good Stream cipher.