I've done research on ciphers and cryptography a little bit, so based on my understanding I made up some operations you can do on paper (not needing a computer) to transform text into something seemingly random, but also it has to be reversible with a key. I try to make it so that it doesn't fall into the common traps that some older ciphers fell into like double letters are the same like with simple substitution ciphers. Also I wanted it to be reusable unlike with a one-time pad, in my case I like when the key is hidden in the encrypted message.

I haven't found anyone to test out any ciphers yet, but I also haven't looked too hard. I'm sure some people enjoy deciphering for fun (I don't have the smarts or at least the time for that).