1. Authentication and handoff protocols for wireless mesh networks
PhD Security Oral Exam
Naif Alamri

2. Outline Background WMN architecture WMN components WMN challenges
Current solutions
Related work
Future work
Auth HandOff WMN / N. Alamri
1/15/2019

3. Background Mesh topology IEEE 802.11s (2003 – 2011) Multi-hop links
Features: self-organization, self-configuration, self-healing
Advantages: cost effective, scalable, fault tolerant, increased range
Applications:
- Last mile broadband access from homes
- Backbone for enterprise networks
- Extended the range of other networks such as WiMAX
- On the fly command centers for emergency response teams, military, etc.
Auth HandOff WMN / N. Alamri
1/15/2019

4. WMN Architectures Three WMN architectures: Infrastructure WMN
Dedicated mesh routers connected via mesh links
Connect to the Internet using gateways
Integrate with wired and wireless networks (bridging or gateway)
Client WMN
No dedicated mesh routers
Clients perform routing, configuration, and maintenance
Hybrid WMN
Combines the features of infrastructure and client WMNs
Client WMN  High throughput, multiple paths
Infrastructure WMN  Integration with other radio technologies, reduce power consumption.
Auth HandOff WMN / N. Alamri
1/15/2019

5. WMN Architectures Infrastructure WMN Hybrid WMN
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1/15/2019

6. WMN Components Mesh router:
Dedicated mesh routers connected via mesh links
Connect to the Internet using gateways
Integrate with wired and wireless networks (bridging or gateway)
Can improve the capacity of the network by using multi-channel single-radio (MCSR) or multi-channel multi-radio (MCMR)
Mesh client:
Mobile or stationary, power constrained
Mostly single radio.
Mesh gateway:
Connect to the Internet
Interoperability between WMNs and other wired and wireless networks
Auth HandOff WMN / N. Alamri
1/15/2019

7. WMN Challenges Routing: Multi-hop, Multi-path, Multi-radio
Reactive or Proactive
self-organization, self-configuration, self-healing
Scalability (overhead), Mobility (handoff)
Hybrid Wireless Mesh Protocol (HWMP)  Ad hoc On Demand Distance Vector (AODV) + Radio-Aware metric
Security:
Confidentiality, Availability, Integrity, authenticity
Privacy  Anonymity and Unlinkability
Power Efficiency:
Power constrained clients.
QoS:
Path selection, Guarantees, Network capacity, Fairness, Interference
Auth HandOff WMN / N. Alamri
1/15/2019

8. 802.11i Introduced in 2004 Enhanced security at MAC layer
Also known as Robust Network Security (RNS)
Advantages: data protection, mutual authentication, key management
Authentication and Confidentiality using WPA2: AES + Counter-mode Cipher Block Chaining Message Authentication Code (CBC-MAC) Protocol (CCMP)
Auth HandOff WMN / N. Alamri
1/15/2019

9. 802.1x Part of 802.11i Port-based access control
Three elements: Supplicant, Authenticator, Authentication Server
Port types: Controlled, Uncontrolled
Extensible Authentication protocol (EAP)
Transport protocol used by 802.1X
Flexible framework
Different authentication methods: passwords, certificates, Kerberos, smart cards
Auth HandOff WMN / N. Alamri
1/15/2019

10. EAP authentication methods
EAP-TLS
EAP-PEAP
EAP-TTLS
Developed By
IETF
Cisco, Microsoft, and RSA
Funk Software and Meetinghouse
Mutual Authentication
Yes
Secure Links
TLS Tunnel
Authentication method
X.509 Certificates
MS-CHAPv2, generic
token card, and EAP-TLS
CHAP, PAP, MS-CHAPv2, and EAP methods
Certificate Required
Both sides
Server side
Protect User Identity No
Auth HandOff WMN / N. Alamri
1/15/2019

11. Security in WMN EAP-TLS for authentication, No fast handoff
Extends Robust Security Network Association (RSNA) with Mesh Security Association (MSA)
Two key holders: Mesh Authenticator (MA), Mesh Key Distributor (MKD)
802.11s provides secure association between MA and MKD
Key hierarchy:
Secure link for initial authentication
Key generation and distribution
Auth HandOff WMN / N. Alamri
1/15/2019

12. WMN key hierarchy Phase 1: Secure links
Supplicant and MKD establish key hierarchy
Mutually generate Pairwise Master Key (PMK-MKD) using Pre-Shared Key (PSK) or Master Session Key (MSK)
Mutually generate PMK-MA; deliver to MA using MSA
Phase 2: Key generation and distribution
Pairwise Transient Key (PTK) derived using PMK-MA
Group Transient Key (GTK) derived using PMK-MA
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1/15/2019

13. WMN Authentication and key generation
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1/15/2019

14. Related Work
"PAPAR: Pairing Based Authentication Protocol with Anonymous Roaming for Wireless Mesh Networks“ by Sultan et al. (IEEE ICIT, 2014)
AS generates a roaming key for each Mesh Access Point
Roaming clients can be authenticated using the roaming key of the old MAP
AS generates a secondary key and pseudo ID for each mesh client
Provides anonymity and unlinkability
"An efficient authenticated key establishment scheme for wireless mesh networks“ by He et al. (IEEE GLOBECOM, 2010)
A distributed authentication key establishment scheme (AKES) for federated WMNs
AS distributes some information to MAPs and clients
Information + IDs are used to establish secure connections
Auth HandOff WMN / N. Alamri
1/15/2019

15. Related Work
“Ticket-based handoff authentication for wireless mesh networks” by Xu et al. (Computer Networks, 2014)
For handoff only, Not initial authentication
AS generates tickets using a master key shared with MAPs
Ticket used to generate session key
No privacy, No unlinkability
"Efficient authentication for fast handover in wireless mesh networks“ by Li et al. (Computer & Security, 2013)
AS generates multiple tickets for each client
One-hop mutual authentication between MAP and client
MAP broadcast tickets to neighbors  minimize delay and traffic overhead
AS doesn’t participate in handoff
Privacy  pseudo IDs
Auth HandOff WMN / N. Alamri
1/15/2019

16. Future Work Task #1: Develop an authentication protocol
Design a fast and secure mutual authentication protocol
Design a secure key distribution system
Add other features such as two-factor, privacy, flexibility
Task #2: Develop a handoff protocol
Design a ticket-based handoff protocol
Design a re-authentication method for seamless roaming
Task #3: Test and security evaluation
Test the new protocols using a network simulator such as NS3
Build a small testbed to conduct tests and security analysis
Design or use existing security evaluation framework for further assessments.
Auth HandOff WMN / N. Alamri
1/15/2019

17. Questions
&
Feedback
Auth HandOff WMN / N. Alamri
1/15/2019