Log in Linux with an USB Pen Drive

Recently I had the idea in increase the security of my Netbook, so I think if it's possible to keep an user session only if an determinated USB pen drive is plugged. I have made an research and I found that there are already some tools to do that.
One of the most popular is pam_usb tools, this tool provides, among other things to do:

• Password less authentication, use USB stick for that;
• Two-factor authentication. USB stick and password to authenticate the user.
• Support for all kind of removable devices (SD, MMC, etc);
• It works with any application supporting PAM, such as su, any login manager (GDM, KDM), etc.

 How to install:
 First install needed packages:

apt-get install libpam-usb pamusb-tools

Connect the pen drive and add it to any name.
Note: Check if it's only one pen drive connected;
Note2: The data in pen drive is not erased.

pamusb-conf –add-device token

Now add the user account associated to that pen drive.

pamusb-conf –add-user youruser

Note: Answer all questions with 'yes'.

Check if all process is done correctly: 

pamusb-check youruser

If it says: Access Granted it's all ok.

Finally you must add " auth sufficient pam_usb.so" to file /etc/pam.d/common-auth.

From now you can login with your USB pen drive, but it's not all you can run an script and perform some action...For more information please visit the official page.