AES with linear S-Box

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If the AES S-Box is replaced with a linear or affine transformation, for instance the identity mapping $sigma(x)=x$, does the cipher become entirely affine and hence trivially weak?







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    up vote
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    If the AES S-Box is replaced with a linear or affine transformation, for instance the identity mapping $sigma(x)=x$, does the cipher become entirely affine and hence trivially weak?







    share|improve this question






















      up vote
      2
      down vote

      favorite









      up vote
      2
      down vote

      favorite











      If the AES S-Box is replaced with a linear or affine transformation, for instance the identity mapping $sigma(x)=x$, does the cipher become entirely affine and hence trivially weak?







      share|improve this question












      If the AES S-Box is replaced with a linear or affine transformation, for instance the identity mapping $sigma(x)=x$, does the cipher become entirely affine and hence trivially weak?









      share|improve this question











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      asked Aug 10 at 11:47









      conchild

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          does the cipher become entirely affine and hence trivially weak?




          Yes; the AES sbox is the only source of nonlinearity (the ShiftRows and MixColumns are linear, and AddRoundKeys for a fixed key is affine), and so if you replace it with a linear/affine one, the entire cipher becomes affine.






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            1 Answer
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            up vote
            6
            down vote



            accepted











            does the cipher become entirely affine and hence trivially weak?




            Yes; the AES sbox is the only source of nonlinearity (the ShiftRows and MixColumns are linear, and AddRoundKeys for a fixed key is affine), and so if you replace it with a linear/affine one, the entire cipher becomes affine.






            share|improve this answer
























              up vote
              6
              down vote



              accepted











              does the cipher become entirely affine and hence trivially weak?




              Yes; the AES sbox is the only source of nonlinearity (the ShiftRows and MixColumns are linear, and AddRoundKeys for a fixed key is affine), and so if you replace it with a linear/affine one, the entire cipher becomes affine.






              share|improve this answer






















                up vote
                6
                down vote



                accepted







                up vote
                6
                down vote



                accepted







                does the cipher become entirely affine and hence trivially weak?




                Yes; the AES sbox is the only source of nonlinearity (the ShiftRows and MixColumns are linear, and AddRoundKeys for a fixed key is affine), and so if you replace it with a linear/affine one, the entire cipher becomes affine.






                share|improve this answer













                does the cipher become entirely affine and hence trivially weak?




                Yes; the AES sbox is the only source of nonlinearity (the ShiftRows and MixColumns are linear, and AddRoundKeys for a fixed key is affine), and so if you replace it with a linear/affine one, the entire cipher becomes affine.







                share|improve this answer












                share|improve this answer



                share|improve this answer










                answered Aug 10 at 14:54









                poncho

                84.8k2127214




                84.8k2127214






















                     

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