Extending the GSM/3G Key Infrastructure DIMACS Workshop on Mobile and Wireless Security November 3, 2004

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Extending the GSM/3G Key InfrastructureDIMACS
Workshop on Mobile and Wireless SecurityNovember
3, 2004

• Scott B. Guthery
• CTO, Mobile-Mind
• Sguthery_at_mobile-mind.com

Mary J. Cronin Professor of Management Boston
College Cronin_at_bc.edu
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Outline

• SIM for Mobile Network Authentication
• SIM for Internet Authentication
• SIM for Local Authentication

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Subscriber Identity Module

• Integral part of GSM security from the start
• Holds secret key Ki
• other copy held by subscribers network operator
• 8-bit processor, 8KB EEPROM, file system,
  cryptographic algorithms

Identity token with a wireless connection to an
authentication and billing service
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GSM/3G Authentication
1) Identity
2) Identity
SIM
Visited Network
Home Network
3) Challenge Response
4) Challenge
5) Response
Ki
Ki

• Roaming is the stepping off point for extending
  the GSM/3G key infrastructure
• Visited network authenticates without being in
  possession of Ki

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SIM for Internet Authentication

• EAP-SIM uses SIM for Internet authentication
• visited network is an EAP authenticator
• draft-haverinen-pppext-eap-sim-14.txt
• Uses GSM/3G authentication but generates a
  stronger session key

Internet Service
SIM
EAP Authenticator
Home Network
Ki
Ki
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SIM Toolkit

• SIM gives commands to the handset
• display text, get key hit, send SMS, block call
• Operator controls loading of applications
• GlobalPlatform architecture used to manage keys
  for non-operator applications

Application 1
STK
Handset
Application 2
Application 3
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SIM for Local Authentication

• SIM-based authentication and authorization
• visited network is a merchant or a door
• SIM-based cryptographic services
• session keys, certificates, signing, tickets,
  etc.

Local Connections (IR, Bluetooth, etc.)
Operator SIM
Handset
Other SIM
3G Network
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User-Equipment Split

• SIM is in the device needing signing and
  authentication services
• All thats left of the mobile communication
  network is the extended key infrastructure

SIM A
Network Operator
Handset
SIM B
SIM C
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Business Models for SIM Security
ExtensionTheory, Reality and Lessons Learned

• Theory Compelling business and revenue
  opportunities based on leveraging SIM security
• Enormous global installed base of active SIM
  cards
• Over 800 million GSM and 3G handsets and
  subscribers
• Well-established international standards for SIM
  applications and key infrastructure
• Well documented architecture and tools for
  development using SIM Application Toolkit and
  Java Card platform
• Multiple business models from different
  industries (banking, retail, media, IT, health,
  etc.) in search of strong mobile security
  solution will embrace the SIM

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Three Potential Business Cases

• SIM-hosted and authenticated non-telephony
  m-commerce applications and services
• Allow trusted third parties to load applications
  onto the SIM card and share the existing key
  infrastructure to authenticate customers and
  authorize transactions via the wireless public
  network
• SIM-enabled use of mobile handset for
  authenticated and authorized transactions via the
  wireless public network
• Embedded SIMs for authorization of users or
  devices attached to any network, particularly WiFi

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SIM-Hosted M-Commerce Applications

• Business Model Multiple applications are stored
  on a single SIM card to allow subscriber to
  conduct secure banking, make and pay for
  purchases, download and store value, tickets, etc
  to the SIM
• Third party consumer and enterprise applications
  both supported
• SIM application provider gets share of projected
  60 billion plus in m-commerce transactions
• Reality as of 2004
• Technical requirements are in place
• Almost all recent SIMs are multi-application Java
  Card SIMs
• Over 260 million of them are Global Platform
  compliant
• SIM-hosted applications have been scarce
• Limited to small mobile banking pilots in Europe
  and Asia
• Majority of booming m-commerce business has moved
  to handset downloads and back end server-based
  security systems

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SIM-Enabled Security for Mobile Devices

• Business Model Dual-slot handsets provide
  external slot for smart card to conduct secure
  transactions and move value via the SIM, making
  the mobile a cash dispenser, a ticket, a POS,
  etc.
• 1999 launch of dual slot phones to great fanfare
• Datamonitor projected over 32 million such phones
  in use by 2003
• All major handset makers announced plans to
  manufacture them
• Reality as of 2004
• Dual slot phones are hard to find collectors
  items
• Revival of the model via add-on module for
  standard GSM phone to create a mobile POS for
  developing markets
• Way Systems has some initial traction with this
  approach for China

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SIM Authentication in Non-Telephony Networks

• Business Model Embed SIM in WiFi and other
  networked devices or provide SIM-USB token to
  subscribers for authentication and payment for
  WiFi access and roaming
• One solution for problems with 802.11 security
• Potential for portability and roaming on
  different networks
• Possible integration with wireless subscriber
  accounts
• Reality as of 2004
• WLAN Smart Card Consortium attempting to define
  standards
• Commercial deployments increasing but still in
  early stages
• Transat solution launches with 3,500 hotspots in
  the UK (4/04)
• Orange implements in Switzerland (3/04)
• Tartara demonstrates solution with Verisign
  (3/04)
• TSI demonstrates solution with Boingo Wireless
  (5/04)

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Conclusion Still Searching for Clear Business
Case for SIM Extension

• Limited applications to date outside of wireless
  telephony and some notable business failures such
  as dual-slot handsets
• The combined business drivers of a billion SIMs,
  a rapidly growing m-commerce market and unsolved
  mobile security issues continue to bring new
  players and approaches to the table
• Lesson learned Wireless carriers have made
  controlling and guarding the SIM key
  infrastructure a priority over increasing
  revenues through extension
• Carriers have the ability to cut off third party
  access to the SIM platform
• WiFi and non-telephony network authentication
  looks like a good match for the SIM key
  infrastructure, but long-term models may require
  wireless carrier participation