Adding the fingerprint reader as optional authentication is easy.
Get the thinkfinger-0.3 package (http://thinkfinger.sourceforge.net/) compile it. After the make install, you have to adjust /etc/pam.d/common-auth to look like this:
auth required pam_env.so
auth sufficient pam_thinkfinger.so
auth required pam_unix2.so # debug cann be added to see if somethings missing
After adding some fingerprints with the tf-tool to /etc/pam_thinkfinger/[username].bir
you should be able to also authenticate by your fingerprint:
cisco@lap:~> su –
Password or swipe finger:
lap:~ #
In you syslog, you should see:
kerel: input: Virtual ThinkFinger Keyboard as /class/input/input6