$ sudo apt-get update
$ sudo apt-get install libpam-encfs 

libpam-encfs is installed in your system.

Make ensure the libpam-encfs package were installed using the commands given below,

$ sudo dpkg-query -l | grep libpam-encfs *

You will get with libpam-encfs package name, version, architecture and description in a table

libpam-encfs package basic information: