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1

AES S-box DDT is not uniform but it has a higher resistant to differential attacks than DES because of maximum probablity of input output pair of differential is 4/256.


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The difference distribution table for the AES s-box contains mostly probability 2/256 differentials. However, there is a single probability 4/256 for each input/output difference. I uploaded a dump of the table here so that you can see. The code used to produce this table can be found here. Disclaimer: This is my personal github. If by "uniform", you mean ...


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The function $f$ is biased towards the complement of the input $c_{i,j}$, assuming the other two inputs are approximately randomly distributed. As all the values $c_{i,j}$ are public, this means that the output of the function $R_i$, and hence the function $F$ is strongly distinguishable from random (being biased towards a known bit pattern). This isn't an ...


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You can still use differential cryptanalysis. Let $r$ be the number of rounds. If the differential characteristic has probability 1 through the whole cipher, it also has probability one at the output of any intermediate round. Use the characteristic through $r-1$ rounds and decrypt the ciphertext backwards through the last round, subject to hypotheses on ...


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Usually differential cryptanalysis relies on something called the "wrong key randomization hypothesis", which is the assumption that decryption of the last round with the wrong key results in a random difference at the beginning of the last round, while decryption with the correct key will result in the expected difference with the probability of the ...


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Also, differential attacks can be useful in the design of a cipher to strike the right balance between performance (e.g., number of rounds) and security. Let's assume DES initially had 10 rounds and the designers performed a differential attack on that setup. They would have found that 10 rounds were not buying enough resistance against that type of attack ...


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Anyone who begins to develop an attack on primitive XYZ is probably not aware beforehand of what the computational complexity of their attack will turn out to be. Then, the attack is developed and computational complexity becomes known. Just because DES isn't broken by the attack in question does not mean no other ciphers will be. And just because the ...


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Differential cryptanalysis is a very powerful technique that permitted highly practical attacks on many ciphers that were not designed to resist it (e.g. FEAL-4). DES, as it turns out, was designed to be pretty resistant to it, which is why it requires an essentially impractical amount of chosen plaintexts to implement a differential attack on DES. ...



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