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If you ever find yourself logging into your server from machines which you do not have control over (they might have keyboard sniffers) then this is the program for you.

Opiepasswd is program which generates passwords that can be used only once. This will allow you to use untrusted machines to login to your account.

$ opiepasswd -c
[enter a passphrase twice, this will be used to compute your throw-away passwords]

Okay, that’s it. Now login via ssh and you should see something like this:

otp-md5 496 si2845 ext
Password:

The 496 is the password number, and si2845 is the seed. You need to figure out which password to type. To do this use opiekey.

$ opiekey 496 si2845
Using the MD5 algorithm to compute response.
Enter secret pass phrase: [enter your passphrase]
MAE OX SHAW BORE BOON GEE

This means at your password prompt you need to type “MAE OX SHAW BORE BOON GEE” You can press enter before typing it in to turn on echo.

Since you won’t always be at a terminal to compute your opie responses it might be a good idea to print out a list of passwords. You can print out the next 5 passwords in the sequence by using the -n option like this:

$ opiekey -n 5 496 si2845

Even better, if you have a Palm OS device you can download pilOTP (available here: http://astro.uchicago.edu/home/web/valdes/pilot/pilOTP/) which can compute opie passwords.

Note: Can get to the regular password prompt by typing the wrong Opiepasswd