Unanswered Questions

I'm starting to create a puzzle, but I'm going to need a cipher that will be impossible (or at least very difficult) to crack, but can be easily decoded with a key. I first looked at the one-time pad ...

I tried to make them not too boring. The intended solution is very hard so I tried to slightly hint at it by implementing multiple solutions that lead to the same answer. I also tried to make more ...

A sequence of integers between 0 and 9 is as follows: 5, 8, 1, 0, 1, 8, 6, 2, 4, ? What is the next term? Hint:

Here we have the great pyramid. The brand new 50-50, Out-to-In Mega-Splitter™. Fill in the question marks with the next numbers! All the hints you should need are in the question!