# how to compute Bit Independent Criteria on a 4-bit S-box?

The idea of Bit Independence Criterion (BIC ) was introduced by Webster and Tavares . For a given set of avalanche vectors generated by complementing a single plaintext bit, all avalanche variables should be pairwise independent. in https://peerj.com/preprints/26452/ Sankhanil Dey1 and Ranjan Ghosh2,introduce the computation on the s-box values instead of the avalanche values and said that it is balanced then BIC achieved. in this way all s boxes will satisfy BIC table below illustrate the paper computation. i think we have to find the avalanche first and the compute the all possible or total six xored 4-bit BFs on the avalanche vectors using the formula: a+d/a+b+c+d Here, a=(1,1), d=(0,0), b=(1,0), c=(0,1).  • first table introduce what i think. second table which introduced in the paper. note different s-boxes are used. – bassam Sep 3 '18 at 3:54
• what is your question? – hardyrama Sep 3 '18 at 5:52
• please ask a question. – kodlu Sep 3 '18 at 12:58
• @hardyrama, – kodlu How to compute the BIC? – bassam Sep 7 '18 at 20:38
• @ kodlu, which vectors will be used, the avalanche vectors or the s-box vectors directly? – bassam Sep 7 '18 at 20:40