Xlock

sudo make install clean -C /usr/ports/x11/xlockmore/ множество полезных опций, но ничего не выбирал

лочит при запуске, разлочивает при вводе пароля системного (хотя поддержка PAM при установке не была выбрана)

запуск без хранителя экрана xlock -mode blank

Для активации автоматического запуска xlock используется xautolock

-/+timeelapsed Allows you to find out how long a machine is locked  so  you  can complain to an administrator that someone is hogging a machine.

a couple of ways in which xlock can help to automate this process. Firstly, the startCmd option allows xlock to      be configured to run 'ssh-add -D' every time you lock  the  screen,  so       that  your  keys  are  automatically  deleted  from  ssh-agent. If the passphrase on your ssh keys is the same as your password,  then  xlock can also  be  made to re-add the keys to ssh-agent when you unlock the screen, via the pipepassCmd option. This requires a bit of scripting, as the  command  must  read your password from standard input and then automate the interaction with ssh-add to re-add the keys. There is an       example of such a script in the xlock distribution - see etc/xlockssh*