vakoroteev
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 Aug 4 awarded Autobiographer Dec 23 awarded Supporter Dec 23 accepted Two-dimensional S-Box Dec 23 comment Two-dimensional S-Box Thank you. Your explanation of the development of S-Box really helped my understanding of the issue. Dec 22 awarded Editor Dec 22 revised Two-dimensional S-Box deleted 33 characters in body Dec 22 comment Two-dimensional S-Box My cipher is only example. Consider, that I need several different S-boxes. So I need to construct several good S-boxes. My 4-bit S-box with two level of substitution is equivalent to 16-bit S-box with one level of substitution. So if I right, constructing of 4-bit S-box is simpler, than constructing 16-bit S-box. This simplifies the development of encryption algorithm, in that case when it is necessary with several blocks. If I'm wrong, I'll be glad to hear criticism. Dec 22 comment Two-dimensional S-Box I use two different symbols because I want represent that this S-boxes change input message by different way. $S'$ change every row of input message (message is 2-dimensional array 4x4). Output of $S'$ is 2-dimensional array 4x4 too. $S''$ substitute every column of output of $S'$. Dec 22 comment Two-dimensional S-Box $S'$ and $S''$ is same 4-input-bits S-box. Where $S_1$ and $S_2$ is 16-input-bits S-boxes. $S'$ change plain-text by rows, i.e. convert all rows. $S''$ change only columns of output of $S'$. While $S_1$ change all plain-text and $S_2$ change all 16-bit of output of $S_1$ Dec 22 asked Two-dimensional S-Box Nov 21 awarded Student Nov 21 accepted Applying differential cryptanalysis to ciphers with addition mod $2^{32}$ Nov 21 awarded Scholar Nov 21 comment Applying differential cryptanalysis to ciphers with addition mod $2^{32}$ thank you very much for your answer. ((m1 - k1) mod c) - (m2 - k1) mod c) mod c ==> ((m1 mod c) - (k1 mod c) - (m2 mod c) + (k1 mod c)) mod c ==> ((m1 mod c) - (m2 mod c)) mod c. So we get rid of the key. Nov 21 reviewed Approve Applying differential cryptanalysis to ciphers with addition mod $2^{32}$ Nov 21 comment Applying differential cryptanalysis to ciphers with addition mod $2^{32}$ @user8911, thank you for the fix. Nov 21 awarded Custodian Nov 21 reviewed Approve Applying differential cryptanalysis to ciphers with addition mod $2^{32}$ Nov 21 asked Applying differential cryptanalysis to ciphers with addition mod $2^{32}$