Mutating State value on every reply

[Alan DeKok]

Phil Mayers wrote:
> Why does the code do this i.e. xor-ing the eap ID etc. with bytes 3,4,5
> of "State"? I'm sure there's a good reason, but I can't figure out what
> it is.

  Help with debugging weird issues.  If the EAP ID is "hidden" in the
State attribute, we can decode it in later transactions.  A misbehaving
client will send the wrong State, and we'll be able to figure out which
transaction it came from.

  Alan DeKok.