I use one-time passwords to log into some services (one time passwords are great if you don't trust the machine you're logging into because capturing keystrokes won't help an attacker get back in). After swapping my Palm Vx for a IPAQ h4350 I couldn't find a one-time password calculator anywhere. Well, apart from a Java one. And getting a Java runtime onto a Pocket PC was more effort than it looked.

Source code for doing all the hard work already exists, from NRL (called OPIE) and is compatible with S/KEY. So it was just a case of writing a few wrappers and bunging it all together into an application. Fortunately, Microsoft provide eMbedded Visual C++ for free download, so it didn't take much effort.

So without further rambling, here is a one-time password calculator compatible with OPIE and SKEY for the Pocket PC 2003 (worked with a HP IPAQ and probably others). OPIE is under a BSD-style license and I'm not going impose any additional license on my small linking glue.

AWE OTP (23k, Jan 2004)

Download the file above, copy it to your Pocket PC, and run it. It will remember the entries for "Count" and "Seed" that you used last time to speed things up a bit. Any comments, let me know. (gpg signature).

AWE OTP Source Code (200k, Jan 2004)

Source code might work if you have an eMbedded Visual C++ environment, let me know if it doesn't. This is my first Windows program in over 10 years (the last being a network game) and now I have to spend the next ten years trying to erase all thoughts of CStrings and LCPSTRs.

Created: 01 Jan 2004