Hi Yunsong,
Thanks for initiating the discussion. I think the sentences you cited only describe the behavior within a single STA, in which case it will know for sure when a key is installed.
However, as you also pointed out, upon further study of the 4 way handshake and group key handshake, it is quite clear from the text that the completion of the handshake is a good indication that the peer STA has installed the relevant
keys.
12.7.6.8 4-way handshake analysis
…
While message 4 serves no cryptographic purpose, it serves as an acknowledgment to message 3. It is required to inform the Authenticator
that the Supplicant has installed the PTK and GTK and hence can receive encrypted frames.
12.7.7.5 Sample group key handshake
…
b) On receiving the EAPOL-Key frame, the Supplicant validates the MIC, decapsulates the GTK, the IGTK when present and the BIGTK when present,
and uses the MLME-SETKEYS.request primitive to configure the GTK, PN, IGTK, RSC, IPN, BIGTK and BIPN in its STA.#2116)
c) The Supplicant then constructs and sends an EAPOL-Key frame in acknowledgment to the Authenticator.
12.7.9.4 Supplicant state machi…
When processing 4-way handshake message 3, the GTK, IGTK, and BIGTK if present, and
WIGTK if present are decrypted from the EAPOL-Key frame and installed. The PTK shall be installed before the GTK and IGTK.
However, we did miss few subclauses (cited above) in which we should also include the installation of WTK and WIGTK as appropriate. I will go ahead and do that.
Regards,
Rojan
From: Yunsong Yang <yunsongyang1@xxxxxxxxx>
Sent: Tuesday, May 5, 2020 1:09 PM
To: Rojan Chitrakar <rojan.chitrakar@xxxxxxxxxxxxxxxx>
Cc: STDS-802-11-TGBA@xxxxxxxxxxxxxxxxx; Minyoung Park <mpark.ieee@xxxxxxxxx>
Subject: Re: [STDS-802-11-TGBA] Updated tentative agenda for TGba CRC call on [May 4th, Monday, 23:00 ET, 2 hours]
Hi Rojan,
Related to the discussion on CID 7063 that we had today, here is what REVmd D3.2 (on P2630L46) says:
(#1345)Management frame protection cannot be applied until the PTK and IGTK has been established with the
STA. A STA shall not transmit robust Action frames until it has installed the PTK for the peer STA, or in the
case of group addressed frames, has installed the IGTK. The STA shall discard any robust Action frames
received before the PTK and IGTK are installed.
I think determining exactly when a peer has installed a shared key is a trivial issue that should be dealt with by implementation. The sequence of the 4-way handshake defined in the standard has provided sufficient details to guide the
implementation.
Having said that, I am also fine with the revised text that we came up with today for CID 7063, because I would not expect any WUR AP will transmit a Wake-up frame between msg 3 and msg 4 during the 4-way handshake.
I've posted a updated tentative agenda for the TGba CRC call below (new DCN):
Dear all,
I've posted a tentative agenda for TGba CRC call on [May 4th, Monday, 23:00ET, 2 hours]:
There are three motions and four presentations in the agenda.
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