1. Fast and Secure Universal Roaming Service for Mobile Internet Yeali S. Sun, Yu-Chun Pan, Meng-Chang Chen

2. Outline Introduction AAA-enabled Mobile IP Architecture Forming an AAA-enabled Roaming Alliance U-Mobile Token Conclusion Future Work

3. 1. Introduction Three issues are raised in such a communication environment All IP-based roaming environment Security and Accounting management for mobile Internet AAA will incur extra delay when handoff occur Our design goal To provide fast and secure roaming service across multiple service domain Mobile user carry a U-Mobile Token

4. 2. AAA-enabled Mobile IP Architecture Mobile IP and AAA

5. A simple AAA+ Mobile IP Protocol (1)

6. A simple AAA+ Mobile IP Protocol (2) AAA framework need to establish two security relationship in advance Between MN and Home AAA Between Foreign AAA and Home AAA

7. 3. Forming an AAA-enabled Roaming Roaming alliance is pre-configured to share administratively created security associations Roaming alliance have two actors Master domain Creator of the alliance Alliance membership management Member domain Master invite to join the alliance

8. Two phases to join roaming alliance

9. 4. Alliance U-Mobile Token MN will get the authentication package from its home AAA U-Mobile token U-Mobile token has three tasks Authentication of the issuing party Authentication of the token holder Integrity check

10. U-Mobile Token Two security mechanisms are proposed Alliance key pair Alliance service key

11. Alliance key pair Master domain contains three parameters Alliance public key Yalliance Diffie-Hellman q ( a very large prime number) α( a primitive root of q) Master is responsible for rekeying after member join or leave

12. Alliance Service key Mobile User get the fast roaming authentication package X alliance and q and α AAA server determines a random integer X AAA as private key and Y AAA as public key send Y AAA out in the route advertisement message In the AAA server side K allianceSvckey = (Y alliance )X AAA mod q In the Mobile User side K allianceSvckey = (Y AAA )X alliance mod q

13. U-Mobile Token content design userID, serviceClass,homeDomainID,{userID} homedomai nKey, {serviceClass, servieLifeTime, alliancePrivateKey,allianceSvcIndex} userPrivateK ey } allianceSvcKey U-Mobile Token = (roamAllianceID, Y AAA, homeDomainID, nonce, {userID, serviceClass,homeDomainID,{userID} homedomai nKey, {serviceClass, servieLifeTime, alliancePrivateKey,allianceSvcIndex} userPrivateK ey } allianceSvcKey )

14. Fast Roaming Authentication

15. The alliance key pair update and distribution structure

16. How to distribute alliance private key to mobile nodes MN’s alliance private key is out of date, when first time to login service AAAF forward the token to MN’s AAAH for update MN periodically send an alliance private key update request to AAAH AAA server keep a window of the valid alliance key pair

17. Conclusions We proposed a service model called universal roaming service Mobile users belonging to different service operators can fast and securely access network resource with U-Mobile token U-Mobile token successfully achieves the authentication of the AAA server(AAAF,AAAH) and token holder(MN)

18. 6. Future Works Simulation