A question on dynamic wep key

[eaglelei]

I have an Orinoco AP 2000 which can offer EAP-TLS and dynamic wep key. I wondered how dynamic wep key is implemented, so I catched the authentication packets by sniffer. From the packets, I knew that the RADIUS-ACCESS-ACCEPT includes two attributes:"MS MPPE RECV KEY" and "MS MPPE SEND KEY" and I found AP send two EAPOL-KEY packets to the station.

802.1x says that the EAPOL-KEY packet has two encrypted items :key signature and key, which are encrypted by server key and session key generated in the EAP authentication process, then how the AP can get these keys? I guess that AP must use the two MS MPPE attributes to construct the EAPOL-KEY packet, but how?

I want to know the detail or where to find the specification. I am looking forward for your kind reply and thank you very much.

[krook]

Check out RFC 3079 (MPPE) and see if that answers your questions.

[eaglelei]

Thank you, krook!

I just read RFC 2079. I find that the RFC explains how to derive keys for use with MPPE, which is done in Radius Server and Station respectively. My situation is that I have known the keys in an AP, but I don't know how to use these keys to construct a EAPOL-KEY packet.

Thank you all the same.