1. Fast Initial Authentication
January 2010
doc.: IEEE /0059r0
March 2010
Fast Initial Authentication
Date:
Authors:
Name
Company
Address
Phone
Hiroki NAKANO
Trans New Technology, Inc.
Sumitomo-Seimei Kyoto Bldg. 8F,
62 Tukiboko-cho Shimogyo-ku,
Kyoto JAPAN
Hitoshi MORIOKA
ROOT Inc.
#33 Ito Bldg.
Tenjin, Chuo-ku,
Fukuoka JAPAN
Hiroshi MANO
8F TOC2 Bldg Nishi-Gotanda, Shinagawa-ku,
Tokyo JAPAN
Hiroki Nakano, Trans New Technology, Inc.
Hiroki Nakano, Trans New Technology, Inc.

2. The purpose of this presentation
January 2010
doc.: IEEE /0059r0
March 2010
The purpose of this presentation
“Fast Initial Authentication” and any other preparation require cooperation among all layers including IEEE802.11, IP etc. We are focusing on the procedure of IEEE to set up communication channel between AP and Non-AP STA.
This presentation just introduces some ideas to make the procedure faster in order to show their technical possibilities and to help you to consider starting official discussion about “Fast Initial Authentication” in WG.
Hiroki Nakano, Trans New Technology, Inc.
Hiroki Nakano, Trans New Technology, Inc.

3. Why “Fast Initial Authentication?”
March 2010
Why “Fast Initial Authentication?”
We should prepare for “Fast Initial Authentication” because of…
Moving users with HIGH VELOCITY through a cell of AP
HUGE NUMBER of users within reach of each AP
Very SMALL CELL of each AP
See IEEE /0286r0 and come to the tutorial session for more detail
Hiroki Nakano, Trans New Technology, Inc.

4. Quick update contents and push services
March 2010
Quick update contents and push services
You can update new messages and location data while just passing an AP's coverage.
You do not have to stop many times like serious landing operation.
Service provider can distribute the handbill without stopping the foot of the customer.
Pop
New location and presence
Updated new twitters and messages
Get new handbills
Location
Messages
Handbill
No need stop! Just pass through!
Hiroki Nakano, Trans New Technology, Inc.

5. Who consume time for authentication and setting up channel?
March 2010
Who consume time for authentication and setting up channel?
AP Discovery (802.11?)
Association (802.11)
Authentication (802.11, 802.1X)
DHCP (IPv4), RA (IPv6)
ARP (IPv4), NDP (IPv6)
Protocols on more upper layer
Mobile IPv4/6
DNS
VPN
HTTP…
Hiroki Nakano, Trans New Technology, Inc.

6. An Example of Packet Exchange
March 2010
An Example of Packet Exchange
STA AP
RADIUS Server
Home Agent
Beacon
Probe Request
Probe Response
Open System Authentication
Open System Authentication
Association Request
Association Accept
EAPOL-Start
EAP-Request/Identity
EAP-Response/Identity
RADIUS-Access-Request/Identity
RADIUS-Access-Challenge/TLS-Start
EAP-Request/TLS-Start
EAP-Response/TLS-client Hello
RADIUS-Access-Request/Pass Through
RADIUS-Access-Challenge/ Server Certificate
EAP-Request/Pass Through
EAP-Response/Client Certificate
RADIUS-Access-Request/Pass Through
RADIUS-Access-Challenge/Encryption Type
EAP-Request/Pass Through
EAP-Response
RADIUS-Access-Request
RADIUS-Access-Accept
EAP-Success
EAP-Key
DHCP Discover
DHCP Offer
DHCP Request
DHCP Ack
Mobile IPv4 Registration Request
Mobile IPv4 Registration Request
Mobile IPv4 Registration Reply
Mobile IPv4 Registration Reply
Hiroki Nakano, Trans New Technology, Inc.

7. Challenge to minimum procedure
March 2010
Challenge to minimum procedure
We employ too many packets to pile up layers. Can we decrease packets for initial setup?
The least procedure is “single roundtrip.” Can we do that?
Let’s think about IEEE first.
Hiroki Nakano, Trans New Technology, Inc.

8. Assumed Goal Employ just SINGLE round-trip exchange of frames
March 2010
Assumed Goal
Employ just SINGLE round-trip exchange of frames
STA to AP, then AP to STA
Do all things to start user’s data exchange
Association
Authentication
Key Exchange
No direct contract between AP and non-AP STA
‘Authentication Server’ mediates between AP and non-AP STA
For separation of service providers and AP infrastructure
Possibly compatible with existing framework
Old STAs can be still operated together.
Hiroki Nakano, Trans New Technology, Inc.

9. Ideas? Omit Pre-RSNA authentication process
March 2010
Ideas?
Omit Pre-RSNA authentication process
Piggyback authentication information onto Association Request/Response
Piggyback upper information onto Association Request/Response
Hiroki Nakano, Trans New Technology, Inc.

10. Idea 1: Omit Pre-RSNA Auth. Process
March 2010
Idea 1: Omit Pre-RSNA Auth. Process
We use “Open System” authentication on Pre-RSNA framework at anytime.
Anyone using Shared Key auth?
“Open System auth. is a null auth. algorithm. Any STA requesting Open System auth. may be authenticated”
Quoted from section
Nevertheless, it takes ONE round-trip time to do that!
Standard should be changed to allow to run Association process without Open System authentication process.
Any problem occurs?
Hiroki Nakano, Trans New Technology, Inc.

11. Reason of existence of Open System auth.
March 2010
Reason of existence of Open System auth.
“NOTE 3—IEEE Open System authentication provides no security, but is included to maintain backward compatibility with the IEEE state machine (see 11.3).”
Quoted from section b)
Hiroki Nakano, Trans New Technology, Inc.

12. March 2010
Figure 11-6
Hiroki Nakano, Trans New Technology, Inc.

13. Modified Figure? March 2010 Successful Association by new protocol
Hiroki Nakano, Trans New Technology, Inc.

14. Backward Compatibility
March 2010
Backward Compatibility
Old AP
not supporting FastAKM
New AP
supporting FastAKM
Old STA
No problem
Old STA begins to talk in old protocol and New AP speaks in the old protocol.
New STA
New STA tries new protocol but Old AP doesn’t accept.
And then New STA goes in old protocol.
Hiroki Nakano, Trans New Technology, Inc.

15. Idea 2: Piggyback Auth. Info. onto Association Request/Response
March 2010
Idea 2: Piggyback Auth. Info. onto Association Request/Response
Can “Mutual Authentication” be done by just A round-trip of Association Request/Response?
“Single Round-trip Authentication” is a common problem.
STA AP
Authentication Server
Beacon
(Probe Request)
(Probe Response)
Authentication (Open System)
Authentication (Open System)
Association Request
Access Request
Access Response
Association Response (Accept)
Hiroki Nakano, Trans New Technology, Inc.

16. Supposed Service Model
March 2010
Supposed Service Model
(Service Provider)
Authentication Server
Non-AP STA
(Customer)
(Infrastructure) AP
Hiroki Nakano, Trans New Technology, Inc.

17. Relations in Real World
March 2010
Relations in Real World
(Service Provider)
Authentication Server
Non-AP STA
(Customer)
(Infrastructure) AP
Contract to provide wireless access to users specified by Authentication Server (i.e. Service Provider)
Set up secure communication channel to exchange information about users
Contract to provide wireless access via AP infrastructure.
Share information to identify each other properly, e.g. username, password, digital certificate, etc.
Hiroki Nakano, Trans New Technology, Inc.

18. Cryptographic Keys Set up in advance by contract March 2010 AP-KEY
(Service Provider)
Authentication Server
Non-AP STA
(Customer)
(Infrastructure) AP
Set up in advance by contract
AP-KEY
USER-KEY
Hiroki Nakano, Trans New Technology, Inc.

19. Relations in Computer Network
March 2010
Relations in Computer Network
(Service Provider)
Authentication Server
Non-AP STA
(Customer)
(Infrastructure) AP
Secure channel by cryptographic key set up in advance
Encrypted bundle including the followings:
User ID
Key
How can we exchange keys safely?
Hiroki Nakano, Trans New Technology, Inc.

20. Step 1: Make Key on Non-AP STA
March 2010
Step 1: Make Key on Non-AP STA
(Service Provider)
Authentication Server
Non-AP STA
(Customer)
(Infrastructure) AP
TMP-KEY
STA generates a Key from random number generator
Hiroki Nakano, Trans New Technology, Inc.

21. Step 2: Send Encrypted Bundle toward AP
March 2010
Step 2: Send Encrypted Bundle toward AP
(Service Provider)
Authentication Server
Non-AP STA
(Customer)
(Infrastructure) AP
Bundle encrypted by USER-KEY includes the followings:
User’s ID
TMP-KEY
Auth. Server Selector
Hiroki Nakano, Trans New Technology, Inc.

22. Step 3: AP Forwards data to Auth Server
March 2010
Step 3: AP Forwards data to Auth Server
(Service Provider)
Authentication Server
Non-AP STA
(Customer)
(Infrastructure) AP
AP doesn’t see data inside bundle because data are encrypted by USER-KEY which AP doesn’t have any knowledge about.
Select Auth. Server
Auth. Server Selector
Hiroki Nakano, Trans New Technology, Inc.

23. Step 4: Auth Server sends back to AP
March 2010
Step 4: Auth Server sends back to AP
(Service Provider)
Authentication Server
Non-AP STA
(Customer)
(Infrastructure) AP
Send back TMP-KEY to AP
Remind that there is a secure channel by AP-KEY
Auth. Server Selector
Hiroki Nakano, Trans New Technology, Inc.

24. Final Step: AP Acknowledges to STA
March 2010
Final Step: AP Acknowledges to STA
(Service Provider)
Authentication Server
Non-AP STA
(Customer)
(Infrastructure) AP
Now, both share TMP-KEY!
Acknowledge and additional information encrypted by TMP-KEY
Hiroki Nakano, Trans New Technology, Inc.

25. After Exchanging Key… March 2010
(Service Provider)
Authentication Server
Non-AP STA
(Customer)
(Infrastructure) AP
Normal communication encrypted by TMP-KEY
Hiroki Nakano, Trans New Technology, Inc.

26. Authentication Server
March 2010
Attack 1: Fake STA
(Service Provider)
Authentication Server
(Customer)
Fake STA
(Infrastructure) AP
Auth. Server can not extract data from bundle because of lack of USER-KEY.
No USER-KEY shared
Bundle reaches Auth. Server
Hiroki Nakano, Trans New Technology, Inc.

27. Authentication Server
March 2010
Attack 2: Fake AP
(Service Provider)
Authentication Server
Non-AP STA
(Customer)
(Infrastructure)
Fake AP
No secure channel because of no cryptographic key shared
AP can not send anything to Auth. Server
Hiroki Nakano, Trans New Technology, Inc.

28. Attack 3: Fake AP and Fake Auth Server
March 2010
Attack 3: Fake AP and Fake Auth Server
Fake Authentication Server
(Service Provider)
Non-AP STA
(Customer)
(Infrastructure)
Fake AP
Auth. Server can not extract data from bundle because of lack of USER-KEY.
No USER-KEY shared
Bundle reaches Auth. Server
Hiroki Nakano, Trans New Technology, Inc.

29. Attack 4: Man In The Middle of AP and STA
March 2010
Attack 4: Man In The Middle of AP and STA
(Service Provider)
Authentication Server
Non-AP STA
(Customer)
(Infrastructure) AP ?
He can not have TMP-KEY… ?
Normal communication encrypted by TMP-KEY
Hiroki Nakano, Trans New Technology, Inc.

30. Attack 5: DoS by Auth Request
March 2010
Attack 5: DoS by Auth Request
(Service Provider)
Authentication Server
(Customer)
Fake STA
(Infrastructure) AP
Numerous Auth Request
Numerous Auth Request
Hiroki Nakano, Trans New Technology, Inc.

31. Attack 6: DoS by Fake “Auth Failed”
March 2010
Attack 6: DoS by Fake “Auth Failed”
(Service Provider)
Authentication Server
Non-AP STA
(Customer)
(Infrastructure) AP
Fake “Auth Failed” messages ?
Acknowledge and additional information encrypted by TMP-KEY
Hiroki Nakano, Trans New Technology, Inc.

32. Idea 3: Piggyback upper information onto Association Request/Response
March 2010
Idea 3: Piggyback upper information onto Association Request/Response
Association Request/Response can be open to upper layers in order to bring back their information like IP address, Netmask etc.
IEEE can provide framework for this.
STA AP
Authentication Server
Beacon
(Probe Request)
(Probe Response)
Authentication (Open System)
Authentication (Open System)
Association Request
Access Request
Access Response
Association Response (Accept)
With upper network configuration
Hiroki Nakano, Trans New Technology, Inc.

33. March 2010
Difference from
Additional state transition to skip Open System Auth.
Figure 11-6—Relationship between state variables and services
Few additional elements to Table 7-26 Element IDs
Authentication Server Selector (240 temporally)
Bundle for User Information (241 temporally)
Upper layer data
RSN with key obtained by new FastAKM framework
RSN information element (for beacon and probe resp.)
Both Group and Pairwise Cipher Suites are set to CCMP.
AKM Suite is set to the brand-new one!
Define new AKM Suite (00-d is used temporally.)
Assign officially on Table 7-34 AKM suite selectors in future…
Hiroki Nakano, Trans New Technology, Inc.

34. Conclusion Not-so-many changes enables FastAKM framework.
March 2010
Conclusion
Not-so-many changes enables FastAKM framework.
IEEE can help upper layers to be configured quickly.
We need place to keep more technical discussion;
to build and verify authentication method
about any effect of changing standard
to write down detailed specification
Hiroki Nakano, Trans New Technology, Inc.

35. March 2010
Hiroki Nakano, Trans New Technology, Inc.