Skip to main content
added 20 characters in body
Source Link

From this answer, I see that from a mathematical point of view, one could define the $\text{Keccak-}f[25w]$ permutation for an arbitrary value of $w$.

I am interested in the following question: disregarding all properties of the resulting function except the invertibility (because $\text{Keccak-}f[25w]$ is required to be a permutation), is it true that if the value of $w$ is a multiple of $8$ and not a multiple of $5$, the corresponding $\text{Keccak-}f[25w]$ function is invertible (and bijective)? If notthe answer is “No”, then how to determine whether a particular $w$ is suitable (assuming that $w$ is required to be a multiple of $8$)?

From this answer, I see that from a mathematical point of view, one could define the $\text{Keccak-}f[25w]$ permutation for an arbitrary value of $w$.

I am interested in the following question: disregarding all properties of the resulting function except the invertibility (because $\text{Keccak-}f[25w]$ is required to be a permutation), is it true that if the value of $w$ is a multiple of $8$ and not a multiple of $5$, the corresponding $\text{Keccak-}f[25w]$ function is invertible (and bijective)? If not, how to determine whether a particular $w$ is suitable (assuming that $w$ is required to be a multiple of $8$)?

From this answer, I see that from a mathematical point of view, one could define the $\text{Keccak-}f[25w]$ permutation for an arbitrary value of $w$.

I am interested in the following question: disregarding all properties of the resulting function except the invertibility (because $\text{Keccak-}f[25w]$ is required to be a permutation), is it true that if the value of $w$ is a multiple of $8$ and not a multiple of $5$, the corresponding $\text{Keccak-}f[25w]$ function is invertible (and bijective)? If the answer is “No”, then how to determine whether a particular $w$ is suitable (assuming that $w$ is required to be a multiple of $8$)?

Tweeted twitter.com/StackCrypto/status/1093207896001822720
Source Link

What are the values of $w$ such that the corresponding $\text{Keccak-}f[25w]$ function is invertible (bijective)?

From this answer, I see that from a mathematical point of view, one could define the $\text{Keccak-}f[25w]$ permutation for an arbitrary value of $w$.

I am interested in the following question: disregarding all properties of the resulting function except the invertibility (because $\text{Keccak-}f[25w]$ is required to be a permutation), is it true that if the value of $w$ is a multiple of $8$ and not a multiple of $5$, the corresponding $\text{Keccak-}f[25w]$ function is invertible (and bijective)? If not, how to determine whether a particular $w$ is suitable (assuming that $w$ is required to be a multiple of $8$)?