# Tag Info

## New answers tagged permutation

2

Each one of your first two sentences has a mistaken premise: you're starting from some assumptions that aren't actually true. DES does not use small PRPs for saving memory. It doesn't use small PRPs at all. The DES S-boxes are not PRPs. The DES F-function is not a PRP. A SPN does not use several small PRPs for saving memory. A SPN doesn't use PRPs at ...

3

At some level, there is no essential difference. Certainly, there is no difference in the distribution on the random variable $O$ vs $f$. However, there is a potential difference in how the terms are typically used. If we say that $O$ is a random (bijective) oracle, then we are usually implicitly hinting that it is available to everyone: the legitimate ...

Top 50 recent answers are included