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I'm studying the paper: "Improved Impossible Differential Cryptanalysis of Rijndael and Crypton".

I've got two questions:

  1. Please explain the calculation performed for step 5?

Step 4 requires about $2^{123.5} (= 2 \times 2^{64} \times 2^{58.5})$ one round operations. Step 5 requires about $2^{119}$ one round operations since:

$2^{64} \times 2 \times 2^{32}\{1 + (1 - 2^{-22}) + (1 - 2^{-22})^2 + \ldots + (1 - 2^{-22})^{2^{28.5}}\} \approx 2^{119}$

  1. How many pairs are needed to delete $k_0$'s corresponding to $k_6$

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    $\begingroup$ Include a description of the step or a link to the paper please $\endgroup$
    – kodlu
    Commented May 2 at 14:29
  • $\begingroup$ @kodlu It was added to the question. I'll be danged if I convert that to MathJax though :) $\endgroup$
    – Maarten Bodewes
    Commented May 3 at 1:05
  • $\begingroup$ This attack article has little application with those fixed plaintexts and 6 rounds and $2^{91.5}$ chosen plaintexts. $\endgroup$
    – kelalaka
    Commented May 4 at 8:51

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