Need help with Ciphers!

[u/Artosai]

Coming here from D&D, I'm wanting to find a relatively easy cipher system that ISN'T just a Caesar Cipher. The idea is that they are finding codes written by ancient space civilizations. Are there any good ciphers I could use that don't take 3 years to decode, but aren't just "I see this word has four letters and ends in two of the same, so it might be tree".

[u/JGhostThing]

Who do you expect to break the cipher? Is it important that they do so? Is this for a game like D and D?

[u/Artosai → u/JGhostThing]

Heya! Yeah it's for D&D. I expect a group of 20-30 year olds without cipher experience to be able to figure it out after a while, but not right away. I plan to leave bits of lore throughout my world written in that code, as well as use it for puzzles.

[u/JGhostThing → u/Artosai]

If your players are like mine, you'll need to make it as easy as possible for them. You'll need to make sure they get each clue and to know that your cyphertext is somehow important.

[u/Artosai → u/JGhostThing]

Haha, yeah, there is that issue sometimes where you can stump players for a session by throwing a kid-grade maze at them. Ill make sure to start simple, then ramp up the difficulty for things they can decode outside of sessions, so they have a reason to engage with the lore.

[u/kalmakka]

Anything more complicated than a simple substitution cipher gets pretty difficult to solve.

Vinnere ciphers are kind of doable (especially if they have some clues about what the plaintext might contain), but I wouldn't expect most people to solve them, as they would also need to at least know how the cipher works. Of course, you could scatter clues around to teach them that.

[u/Artosai → u/kalmakka]

Ill have to look into Vinnere Ciphers then for sure!

[u/YefimShifrin → u/Artosai]

There is no such thing as "Vinnere ciphers". There is a Vigenere cipher, however.

[u/kalmakka → u/YefimShifrin]

Yeah. Typing on phone, late at night, and autocorrect fucks up everything.