If xlockmore is built with the "pam" option:
In order to make unlocking work, you need to add an
xlock file to your pam configuration directory (usually
/etc/pam.d).  You can find a sample file in:

    @EGDIR@/pam.d/xlock-NetBSD

On  NetBSD, the "pam_pwauth_suid.so" module can be used to authenticate
against a shadow password database. Note that use of this module might
allow programs with your privileges to get a copy of your plaintext
password as typed in for unlocking. The advantage is that with that
module, the suid bit of the

    @PREFIX@/bin/xlock

executable can be removed.
Per default, xlockmore is installed setuid root. Since this is a
relatively complex program, there is the risk of other exploits.