Many times people write down their passwords on paper. Instead of them writing it in plain text, what techniques are there to make things more difficult yet not too much of a pain for the password owner to decrypt?
The idea is not too prevent a security expert from decrypting it, but just to make it harder for someone who finds your password written on paper.
You could think up some easy pattern, trick or algorithm that you can do in your head and then keep it secret. An example would be in the TV series The wire where they would have pager numbers where to decode they would have to 'jump over' the 5 of the keypad, so 789 would become 321.
Invisible ink if you have CD's at hand just point your phone LED through it and you got a black light (Not safe but good overall because if you have people passing your notebook through black screen maybe you have a bigger problem at hand?). Personally I use qrcodes for no sensitive passwords (not in plain text, some are images, some sound and some encrypted strings that get decripted only when my usb is plugged into the pc) still all of this methods were more of a "fun" project than anything else as they are not failure proof.
