# Lineary of Sbox in DES

I'm not a mathematician, and i would like to understand in the most concise way (if possible) why choosing linear S-Box functions makes the DES algorithm attackable. Thanks

• Make them identity of the first 4 input? Oct 16 '19 at 13:51
• Can you write an example ? Oct 16 '19 at 14:15
• \begin{align} S:\{0,1\}^6&\to \{0,1\}^4\\ S(a,b,c,d,e,f) &\mapsto (a,b,c,d) \end{align} Oct 16 '19 at 15:08
• see this answer, for example crypto.stackexchange.com/questions/51017/… Oct 16 '19 at 21:32
• and this one crypto.stackexchange.com/questions/63693/… Oct 16 '19 at 21:33