The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 03, 2011
Filed:
May. 29, 2009
Henry S. Ptasinski, San Francisco, CA (US);
Henry S. Ptasinski, San Francisco, CA (US);
Broadcom Corporation, Irvine, CA (US);
Abstract
A method and apparatus for providing improved security and improved roaming transition times in wireless networks. The same pairwise master key (PMK) from an authentication server can be used across multiple access points and a new pairwise transition key (PTK) is derived for each association of a station to any of the access points. A plurality of access points are organized in functional hierarchical levels and are operable to advertise an indicator of the PMK cache depth supported by a group of access points (N) and an ordered list of the identifiers for the derivation path. Access points in each level in the cache hierarchy compute the derived pairwise master keys (DPMKs) for devices in the next lower level in the hierarchy and then deliver the DPMKs to those devices. An access point calculates the PTK as part of the security exchange process when the station wishes to associate to the access point. The station also computes the PTK as part of the security exchange process. The station calculates all the DMPKs in the hierarchy as part of computing the PTK. The method and apparatus allow the cache depth to vary per station, but it remains constant for a given station within a key circle.