1. Project: IEEE 802 EC Privacy Recommendation Study Group
Dec 2014
Project: IEEE 802 EC Privacy Recommendation Study Group
Submission Title: Secure Moderated Random MAC Addresses
Date Submitted: Dec 10, 2014
Source: Robert Moskowitz, Verizon
Address 1000 Bent Creek Blvd, MechanicsBurg, PA, USA
Voice:+1 (248) ,
Re: KMP TG9 Closing Report for Sept 2014 Session
Abstract: Secure Moderated Random MAC Addresses
Purpose: To Securely Moderate Random MAC Addresses
Notice: This document has been prepared to assist the IEEE P802 EC. 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 acknowledges and accepts that this contribution becomes the property of IEEE and may be made publicly available by P802 EC.
Robert Moskowitz, Verizon

2. Secure Moderated Random MAC Addresses
Dec 2014
Secure Moderated Random MAC Addresses
Conference Call
Dec 10, 2014
Robert Moskowitz, Verizon

3. Dec 2014
Problem Statement
Free for all in Local Scope MAC address space
Randomized address selection has no method of dealing with collisions
Even if full 46 bits remain available
802 architecture calls out for use of an address moderator if Local Scope is used
A moderator should introduce yet another attack point
Robert Moskowitz, Verizon

4. A simple Moderator Protocol
Dec 2014
A simple Moderator Protocol
Client informs moderator of MAC address it will use
Moderator either accepts or rejects
What constitutes a reject.
How does the moderator know?
No way for Moderator to recognize duplicates
Sounds a bit like DHCP
Robert Moskowitz, Verizon

5. And crypto signing of request
Dec 2014
And crypto signing of request
The client can digitally sign the address request
The moderator can now recognize different clients using the same address and reject the late-comer
But what design won't add yet another attack point?
Replay attacks for signed requests
Resource attacks against the crypto operations
Probably more
Robert Moskowitz, Verizon

6. A simple secure exchange
Dec 2014
A simple secure exchange
Use ECDH
Moderator BEACONs its ECDH key
Client derives address from its ECDH key
Client MICs its request with ECDH shared secret
Including ECDH key
Moderator ACK/NAKs request
MICed with ECDH shared secret
Fits well within BEACON/ASSOCIATE mechanism
Fits well within DHCP
Devil is in the Details
Robert Moskowitz, Verizon

7. Dec 2014
DISCUSSION
Robert Moskowitz, Verizon