NON LINEAR FEEDBACK STREAM CIPHER

Abstract

The main aim of this paper is to develop a new generation and innovative security software for applications. We proposed new stream cipher called NLFS. NLFS means Non-linear feedback stream cipher, which is a fast and secure stream cipher for egovernance applications. This stream cipher uses AES secure non-linear function and AES key generation. NLFS uses primitive polynomial generated S-boxes in byte substitution step. NLFS uses two similar AES round functions and these two proceed parallelly to produce key-stream. Non-linear *function of NLFS has AES nonlinear function steps (add-round key, byte substitution, mix column, shift rows) and it extra includes value-based rotation step. In value based rotation step it rotates each 8-bit word by its first 3-bit (decimal) value.NLFS have two modes basic mode that is synchronous mode and self synchronous mode. In synchronous mode key stream is independent of plain text and cipher text. In selfsynchronous mode key stream generation depending on cipher text. In self synchronous mode generated keystream update first 512-bit buffer and cipher text update the second buffer.