wanna know a super duper amazing secret digital communication method some CIA field agents use? gmail. 🤓 except a team will use the same account, leaving messages in the drafts folder in unsent emails, which are deleted when read.
ISIS did this: Meet on private online server for 1on1 pvp game. Shoot letters in walls for messaging. Exit server
wooden signs in minecraft would work.
You can set a server-side max value for things like bullet-holes, so they just dissapaer automatically when more impacts are happening, They also used the email-draft-scheme, but that was insecure because of nsa-compromised email- servers/hosters. Impacts are just coordinates in space, no real letter will be saved on any device ever.
I'm sure central authority can set see your drafts?