[Dovecot] How to make pops

[mickael.choisnard at free.fr]

Hi,
I use dovecot (pop) with gentoo but it's not securize.
I would like to use pops but i don't how to do this.
I think i have to use certificates...

This my dovecot.conf :
protocols = imap imaps pop3 pop3s

imap_listen = *
pop3_listen = *
imaps_listen = *
pop3s_listen = *
ssl_disable = no
login = imap
login = pop3
default_mail_env = maildir:%h/.maildir
mbox_locks = fcntl dotlock
auth = default
auth_mechanisms = plain
auth_userdb = passwd
auth_passdb = pam dovecot
auth_user = root
auth_verbose = yes
auth_debug = yes

Thanks for your help