YubiText and 3-factor password authentication

As I said in the last post, I obtained YubiKey USB tokens and started to play with it. One of the programs I made is YubiText, it allows to input text when a YubiKey is plugged. For instance, one can use it as a way to type a password. This post will describe how it works and how I use it to have something I call 3-factor password authentication.

YubiKey USB security token

I recently obtained YubiKeys from Yubico. It's a USB hardware token able to act as a keyboard device to input characters (a HID) and also has a little button. It supports different modes:

• Yubico OTP Mode: Yubico implementation + server
• OATH-HOTP Mode: standard HOTP as per RFC 4226
• Static Password Mode: output the same static string
• Challenge Response Mode: no HID, software challenges the token and gets a response

PPTP VPN and policy routing on user

The first part of this post describes how to use PPTP VPN on Linux, in command-line and not GUI. The second part, actually independent of VPN, describes how to set up policy routing for a user, in order to have all traffic from that user to go through a specific interface (e.g. the VPN interface).