None.
password [crypted_pw]
Present a crypted password in your “.screenrc” file and screen will
ask for it whenever someone attempts to resume a detached session. This
is useful if you have privileged programs running under screen and you
want to protect your session from reattach attempts by another user
masquerading as your uid (i.e. any superuser.) If no crypted password is
specified, screen prompts twice for typing a password and places its
encrypted form in the paste buffer.
Default is “none”; this disables password checking.
None yet.