Patent ID: 7275157

Claim:
A method of reducing handoff latency of a mobile node (MN) roaming between access points in a wireless network (WLAN), the method comprising: authenticating the mobile node (MN) with an access point (AP) to produce a pairwise master key (PMK); establishing a pairwise transient key (PTK) as a link layer session key to provide secure communication of 802.1X messages and 802.11 data between the mobile node and the access point; associating the mobile node with the access point disposed on said wireless network, wherein said associating includes issuing an association request by said mobile node to the access point including signature information indicative of the mobile node holding a fresh/live pairwise transient key; validating the signature information by the access point; delivering a protected group transient key (GTK) from the access point to the mobile node, the group transient key being used to protect broadcast communication of the access point comprising generating an association response to send to the MN containing an encrypted field protecting the GTK and including signature information indicative of the AP holding the same fresh/live key PTK as the MN; validating the signature information by the MN and storing the encrypted GTK for use in multicast communications by the AP; and forwarding a re-association confirmation message from the mobile node MN to the access point AP to confirm receipt of the group transient key GTK by the mobile node MN; wherein said establishing establishes said pairwise transient key PTK before said associating is initiated; wherein said issuing the re-association request by the mobile node MN includes issuing a resuscitation request as Authenticate PTK (SRandom, PTKID MIC); wherein said validating and said delivering includes delivering a re-association response from the access point AP to the mobile node MN as Authenticate PTK (ARandom, SRandom, PTKID, GTK, GTKID, MIC), deliver encrypted group key; and, wherein said forwarding the re-association confirmation message includes forwarding a re-association confirm from the mobile node MN to the access point AP as Group Key Confirm (ARandom, MIC).