Some ciphers are talked about here, but I don't see an answer, are they strong enough, or are non-computer ciphers more or less just a toy and one should abandon using them for practical purposes?
I'm looking for a toy hash function, where the idea is to have high school students break (i.e. find a collision) a hash function by hand, in order to teach them how one way functions and hashing ...
Can someone explain how to find inverses in truncated polynomial rings manually (i.e. on pen and paper)? As an example from the tutorial: Example. Take $N=7$, $q=11$, $a=3+2X^2-3X^4+X^6$. The ...