I've been reading a lot about WEP recently and why it was bad. To make sure I understand it, I've been writing scripts to show how it works and highlight its vulnerabilities. But I want to have a full understanding from start to finish, and I can't find what I need for the very beginning.
Since WEP can operate on four keys, something needs to be able to generate four keys. My router can do this based off a passphrase. If I put 'badpw' as the passphrase, I get the keys:
If I enter the same passphrase on http://www.wepkey.com/, I get the same four keys. So its clear that the same algorithm is used in both cases, but I can't for the life of me find it.
So, what would the psudocode be to derive those four WEP keys from a passphrase?