Walsh Hadamard transform and cryptographic properties in stream cipher
R. Girija, Pramod Kumar, Meenakumari · 2016
In this paper, we investigate the cryptographic properties of stream cipher and generalities of Walsh-Hadamard transform. Boolean functions play a great significance role in the design of stream cipher. It composes several LFSR (Linear feedback shift register) and a non-filtering Function which produces the output. Predominant cryptographic properties for constructing non filtering function are balancedness, non-linearity, correlation immunity, propagation criteria, and inexistence of linear structure. The tool for studying properties of Boolean function is WALSH-HADAMARD transform. It is the characteristic 2 case of DFT and it is used for computation of non-linearity. It also measures the correlation between Boolean function and all linear Boolean function. All of the cryptographic properties areconnected with Walsh transformation.