Generate Google Authenticator OTPs with a TI89?

[wyager]

Correct me if I'm wrong but if you can generate the codes, then anyone can do it which means it's useless. I thought most of these keys are salted with some specific to your account and I doubt youll be able to figure out what it is and I doubt the bank or wherever would tell you.

Most/all OTP tokens generate OTPs based a hash function of either a Secret Key and The Time or a Secret Key and the Number of Keys Generated So Far.

The one I use for work is based on (as far as I can tell) a secret key and a counter. This is probably much less secure than a time-based OTP.

[unclemantis]

Checks mail for yubikey.

Nope!

Maybe Monday! :-(

[divergentdave]

Hey guys, sorry for posting on a dead thread, but I just wrote a TOTP implementation for my TI-89, and I found this via Google. I wanted to let you know that it works!

Unfortunately, my code takes just over one minute to generate an OTP. This is using the TI-Basic language, which is really bad performance-wise. Plus, the bit shift and bit rotate functions keep generating warning messages. You can write programs for the TI-89 in C, so going that route would probably give you an answer in a more usable timeframe.

If there's still any interest in this subject, let me know. I could grab my old cable and upload the files for anyone else curious. Heck, I might take a stab at the C rewrite as my next project.

Edit: Here it is! https://www.github.com/divergentdave/TOTP-89