1. doc.: IEEE 802.11-06/0121r0 Submission January 2006 S. Bezzateev, A. Fomin, M. WongSlide 1 Broadcast Management Frame Protection Notice: This document has been prepared to assist IEEE 802.11. It is offered as a basis for discussion and is not binding on the contributing individual(s) or organization(s). The material in this document is subject to change in form and content after further study. The contributor(s) reserve(s) the right to add, amend or withdraw material contained herein. Release: The contributor grants a free, irrevocable license to the IEEE to incorporate material contained in this contribution, and any modifications thereof, in the creation of an IEEE Standards publication; to copyright in the IEEE’s name any IEEE Standards publication even though it may include portions of this contribution; and at the IEEE’s sole discretion to permit others to reproduce in whole or in part the resulting IEEE Standards publication. The contributor also acknowledges and accepts that this contribution may be made public by IEEE 802.11. Patent Policy and Procedures: The contributor is familiar with the IEEE 802 Patent Policy and Procedures, including the statement "IEEE standards may include the known use of patent(s), including patent applications, provided the IEEE receives assurance from the patent holder or applicant with respect to patents essential for compliance with both mandatory and optional portions of the standard." Early disclosure to the Working Group of patent information that might be relevant to the standard is essential to reduce the possibility for delays in the development process and increase the likelihood that the draft publication will be approved for publication. Please notify the Chair as early as possible, in written or electronic form, if patented technology (or technology under patent application) might be incorporated into a draft standard being developed within the IEEE 802.11 Working Group. If you have questions, contact the IEEE Patent Committee Administrator at.http:// ieee802.org/guides/bylaws/sb-bylaws.pdfstuart.kerry@philips.compatcom@ieee.org Date: January 15, 2006 Authors:

2. doc.: IEEE 802.11-06/0121r0 Submission January 2006 S. Bezzateev, A. Fomin, M. WongSlide 2 Abstract This contribution proposes method for protecting broadcast management frames.

3. doc.: IEEE 802.11-06/0121r0 Submission January 2006 S. Bezzateev, A. Fomin, M. WongSlide 3 Contents Problem statement Maintenance beacon format Proposal overview Summary

4. doc.: IEEE 802.11-06/0121r0 Submission January 2006 S. Bezzateev, A. Fomin, M. WongSlide 4 Existing Proposal in BUMP MUP in BUMP –Security at the expense of overhead –It reduces broadcast to unicast. –When the number of nodes are relatively large, it becomes impractical.

5. doc.: IEEE 802.11-06/0121r0 Submission January 2006 S. Bezzateev, A. Fomin, M. WongSlide 5 Maintenance Beacon Class 3, Broadcast, Periodic, Action Frames Frame format: variables221 Beacon information elements LengthActionCategory It contains information about time interval, etc. It also contains information about broadcast that AP wants to send during this beacon interval.

6. doc.: IEEE 802.11-06/0121r0 Submission January 2006 S. Bezzateev, A. Fomin, M. WongSlide 6 Inclusion of MIC in Maintenance Beacon B i – beacon sent in i-th beacon interval BMF i j – j-th broadcast management frame sent in i-th beacon interval Broadcast destinations –Retrieve and cache MIC from beacon during period i –Verify that Ki=H(Ki+1) –Use Ki to validate the MIC all frames received during period i

7. doc.: IEEE 802.11-06/0121r0 Submission January 2006 S. Bezzateev, A. Fomin, M. WongSlide 7 Proposed Maintenance Beacon Format variables221 Beacon information elements + BIE LengthActionCategory OrderInformation …… xxxBroadcast Information Element

8. doc.: IEEE 802.11-06/0121r0 Submission January 2006 S. Bezzateev, A. Fomin, M. WongSlide 8 Key Structure Use of hashed key chain Bootstrap to IGTK of BUMP Expand IGTK using PRF into intermediate keys K i0 …...K in Set the initial values of each key chain K 0 to the values K i0 …...K in Keys t K j-1 K j K0K0 K j -1 =H(K j ) K 0 – public key j -1 j 1 Repeat when IGTK gets updated

9. doc.: IEEE 802.11-06/0121r0 Submission January 2006 S. Bezzateev, A. Fomin, M. WongSlide 9 Summarize Broadcast management frames are generally known at time of beacon Include MIC of broadcast management frames in Maintenance Beacon Use hashed key chains for the verification keys