1

Given an SBox, how can I generate its component equations (in ANF)?

given in this link: https://en.wikipedia.org/wiki/Algebraic_normal_form

For example, let's say I have this SBox:

$$\{1, a, 4, c ,6 ,f ,3, 9, 2, d, b, 7, 5, 0, 8, e\}$$

kelalaka
  • 48,443
  • 11
  • 116
  • 196
mahima bhatnagar
  • 31
  • 3
  • 2
    Why this answer did not satisfy you? Generate ANF from SBox – kelalaka Sep 30 '20 at 15:42
  • Write the Sbox as columns multiply with $M_k$ and from $y_i$ as the rows of the final matrix. The answer contains the entries of the columns, too. – kelalaka Sep 30 '20 at 15:49
  • Stop me if I'm wrong, but I think that the linked wikipedia article as it stands now oversimplifies when it states "two equivalent formulas will convert to the same ANF"; that's for a stated order of the input variables, which is not trivial in the context. – fgrieu Sep 30 '20 at 15:55
  • I've posted a sageMath answer to the linked question. It may help to you. Closing as dupe. – kelalaka Sep 30 '20 at 16:11
  • @kelalaka answer explained in Generate ANF from SBox is really nice but when i applied the same method on other SBox the required equation is not coming. I just changed SBox matrix and multiply it with given Mobeius matrix. the matrix which is coming from that I made ANF equations row wise. But the required equation is not matching. – mahima bhatnagar Oct 03 '20 at 14:40
  • Well, stick with the SageMath. It is mostly implemented by the academicians and they clearly test it. – kelalaka Oct 03 '20 at 14:46
  • 1
    @mahimabhatnagar Given that your question is no longer "How to get the ANF description from the table" but rather "how to apply a specific method to my sbox and why doesn't it work", I suggest you make a new question that can receive more specific and helpful answers. Please don't forget to link to the relevant methodology Q&A and tell us how and where exactly (as precisely as you can) it seems to have gone wrong with your application. – SEJPM Oct 04 '20 at 14:44

0 Answers0