Indices to measure the cryptographic strength of S-box

Abstract

The vector Boolean functions with good cryptographic requirements are used for designing S-boxes for block ciphers and combiner/filter functions for stream ciphers. The security strength of any crypto algorithm is dependent on the security strength of S-boxes used in the design and immunity to the cryptanalytic attacks. In order to compare the security strength of various crypto algorithms, in this paper, various indices, have been developed based on the cryptographic properties and parameters for immunity to cryptanalytic attacks.

Keywords and phrases:

• Boolean function
• nonlinearity
• propagation characteristics
• global avalanche characteristic
• autocorrelation function