Does anyone know the Linksys Passphrase to WEP Key Algorithm

john2885 · Last edited by john2885 on Tue Apr 25, 2006 1:35 am; edited 1 time in total

Does anyone know (or know of a website that shows) the Linksys algorithm for generating WEP key(s) from a passphrase? I would like to write a small application that will generate a 128-bit WEP key from a passphrase exactly the same way that Linksys wireless routers do.

Alternatively, a free wep key generator (from a passphrase) would also work. I haven't done a lot of searching yet for this. Everything I've seen so far is either commercial or simply provides a way to randomly generate a key (i.e. doesn't support supplying a passphrase).

Please note that I'm not looking for an academic discussion as to how weak WEP is or wheter WPA or some other wireless security is better or worse - I'm just looking for the algorithm.

Thanks.

john2885

I found the algorithm using the source code for the sourceforge.net project WIFI-BOX. It was in the wepkey.c file in the /release/src/router/shared directory.

If anyone is interested, here is the algorithm:

1. Concatenate the passphrase with itself until you hit 64 characters.
2. Return the first 26 characters of the MD5 hash of the string created in the first step.

That works for the first key. I thought I had the C code deciphered for the other 3 keys but so far it isn't working (I'm recoding in PHP and comparing to the output from my router). I'll post a reply if I can get the rest of them working. For everything I do, one key is good enough.