New answers tagged

1

I sent a mail to the Keccak team asking about this, and I got a response from one of the authors (Joan Daemen to be specific). According to him, we actually can instantiate Sponge functions and Duplex objects with a "transformation" in addition to a permutation, the latter of which is what we commonly do. As long as the underlaying (fixed-width) function ...


4

Under a fixed key, $E_K$ is a permutation in the symmetric group of permutations on $2^{128}$ elements. Thus its order divides $(2^{128})!$. If AES is modelled as a random permutation, for a randomly chosen fixed key, the order $N$ of $E_K$ is likely to be near $2^{127}$ as explained in the comment under the question, and indeed $E_K^{N-1}(x)=E_K^{-1}(x)$ ...


Top 50 recent answers are included