/PGP disable|enable|force|info [jid]
 /PGP setkey [jid [key]]

This command manipulates PGP settings for the specified jid (by default the currently selected contact).
Please note that PGP encryption won't be used if no remote PGP support is detected, even if PGP is enabled with this command.  You can force PGP encryption with the "force" subcommand.

/pgp disable [jid]
 Disable PGP encryption for jid (or the currently selected contact)
/pgp enable [jid]
 Enable PGP encryption for jid (or the currently selected contact)
/pgp [+|-]force [jid]
 Enforce PGP encryption, even for offline messages, and always assume the recipient has PGP support.  If a message can't be encrypted (missing key or key id), the messages won't be sent at all.  This option is ignored when PGP is disabled.
/pgp info [jid]
 Show current PGP settings for the contact
/pgp setkey [jid [key]]
 Set the PGP key to be used to encrypt message for this contact.
 If no key is provided, the current key is erased.
 You can use the shortcut-jid "." for the currently selected contact.