This tutorial explains GDM (GNOME Display Manager) modification to support user verification through keystroke-dynamics processing. Modified GDM allows only you to login. If you go ahead and tell your password to a friend. They still won't be able to log in using GDM without knowing the precise method of typing required when entering your user name.
You can create and store a one-way encrypted hash of your keystroke patterns when entering your user name. Add code to GDM to read current keystroke patterns and permit a user to log in when the characteristics are a match.
Many commercial products today provide two-factor authentication on Linux systems. These technologies generally require the purchase of additional hardware and create a closed implementation unsuitable for many environments. The code and processes presented here allow you to implement a low-cost authentication-input system based on the characteristics of how a user types his password into the GDM. Moving beyond examples and into implementation, the modifications to GDM presented here allow you to enhance the security of your computer.