Pizzino

Pizzino (; plural as "pizzini") is an Italian language word derived from the Sicilian language equivalent "pizzinu" meaning "small piece of paper". The word has been widely used to refer to small slips of paper that the Sicilian Mafia uses for high-level communications.
Sicilian Mafia boss Bernardo Provenzano is among those best known for using "pizzini", most notably in his instruction that Matteo Messina Denaro become his successor. The pizzini of other mafiosi have significantly aided police investigations.
Provenzano case.
Provenzano used a version of the Caesar cipher, used by Julius Caesar in wartime communications. The Caesar code involves shifting each letter of the alphabet forward three places; Provenzano's "pizzini" code did the same, then replaced letters with numbers indicating their position in the alphabet.
For example, one reported note by Provenzano read "I met 512151522 191212154 and we agreed that we will see each other after the holidays..." This name was decoded as "Binnu Riina".
Discovery Channel News quotes cryptography expert Bruce Schneier saying "Looks like kindergarten cryptography to me. It will keep your kid sister out, but it won't keep the police out. But what do you expect from someone who is computer illiterate?"