I'm going to setup 2 factor authentication for my database server. I'm using PostgreSQL 9.4 DBMS on Ubuntu 14.10. I need to force two authentication methods for my database server. The authentication can use password and USB device methods. I need to set these methods on Database server(I don't mean operating system authentication)...
I already installed pamusb pakages :

sudo apt-get install pamusb-tools libpam-usb
Although I can add devices on my pamusb config file :

pamusb-conf --add-device MyDevice
I should define pamusb users and authentication methods. I added this lines to pamusb config between <users> tags :

<user id="postgres"> 
I also create new pam module in \etc\pam.d directory with the name "mypam" :

auth        required      pam_usb.so
auth        include       password-auth
account     include       password-auth
and I edited Postgresql pg_hba.conf file:

local   all             all                                     pam        mypam
host    all             all               pam        mypam
host    all             all             ::1/128                 pam        mypam
But it didn't change anything. would you helping me with that? Any little help would be appreciated...