4.10.3.4 Alternate operations with PSK
The following AKM operations represent an alternate operation of using a PSK. This operation has security
vulnerabilities when used with a low-entropy key and is recommended to be used only after taking that into
account. When this operation is carried out, the PMK is a PSK:
— A STA discovers the AP’s security policy through passively monitoring Beacon frames or through
active probing (shown in Figure 4-17). A STA associates with an AP and negotiates a security
policy. The PMK is the PSK.
— The 4-Way Handshake using EAPOL-Key frames is used, just as with IEEE 802.1X authentication,
when an AS is present. See Figure 4-19.
— The GTK and GTK sequence number are sent from the Authenticator to the Supplicant just as in the
AS case. See Figure 4-19 and Figure 4-20.
— If management frame protection is negotiated, the IGTK and IGTK packet number are sent from the
Authenticator to the Supplicant just as in the AS case. See Figure 4-19 and Figure 4-20.
