It is nearly impossible to create a "real" crypto-society as it would take too much time and resources to encrypt all the human to human interactions. Therefore, nearly all encrypted communities are hosted on the Internet with computers aiding the users in the encryption of their interactions.
Usually, such communities employ public-key cryptography to ensure that their users can speak freely amongst themselves with a greatly reduced probability of anyone else eavesdropping on their conversations. It is common for these communities to avoid real-life identifiers, instead supporting anonymity or pseudonymity, so that members know each other by reputation.
Some encrypted societies that exist today are: