From the original Amiga UNIX 2.1 manual. Some things it mentions may not be in this release.
NAME
chkey - change user encryption key
SYNOPSIS
chkey
DESCRIPTION
The chkey command prompts for a password and uses it to encrypt a new user encryption key. The encrypted key is stored in the publickey(4) database. This command should be executed only on the master server for the publickey(4) database.