publickey - public key database
/etc/publickey is a local public key database that is used for secure RPC. The /etc/publickey file can be used in conjunction with or instead of other publickey databases, including the NIS publickey map. Each entry in the database consists of a network user name (which may refer to either a user or a hostname), followed by the user's public key (in hex notation), a colon, and then the user's secret key encrypted with a password (also in hex notation).
The /etc/publickey file contains a default entry for nobody.