1
$\begingroup$

I once read somewhere that the keys determine the S and P boxes. If so, how does that work?

$\endgroup$
  • $\begingroup$ Commenting not answering b/c I'm not sure if I recall correctly. My recollection is that with AES (per your question), the substitution and permutation operations are not key-dependent. However, with some ciphers (e.g. Blowfish), the operations do depend on the key. $\endgroup$ – Dan Nov 2 '19 at 20:54
  • 2
    $\begingroup$ Where did you read that the keys determine the S and P boxes for AES? Considering that AES does not have a P-box as such, the source is suspect. $\endgroup$ – Ella Rose Nov 2 '19 at 22:51
  • $\begingroup$ I think I was mistaking with blowfish then...but if the substitution-permutation boxes are fixed, then anybody can reverse the encryption process right? Now I know if this was true then it wasn't the standard for the government, but still, if they're fixed, how? $\endgroup$ – Ömer Enes Özmen Nov 3 '19 at 15:09
  • $\begingroup$ Have you read the definition of AES, specifically what the steps involved in it are? $\endgroup$ – Ella Rose Nov 3 '19 at 15:23
  • $\begingroup$ @Ella Rose no..but they have to be key independent right? Cuz if they're fixed then anybody can reverse the ciphertext right? $\endgroup$ – Ömer Enes Özmen Nov 3 '19 at 15:29

Browse other questions tagged or ask your own question.