A presentation I gave on behalf of OSDL in 2005.

1. “Who Am I Now?”:
Identity and Mobility
David “Lefty” Schlesinger
Director, Open Source Technologies
OSDL NEPs and Carriers Face-to-Face
© 2006, ACCESS Co. Ltd. All rights reserved. 10 Oct. 2006

2. Do you know me?
 “How can you tell?”—Dorothy Parker, on being told that Pres.
Calvin Coolidge had died
 Identity in the literal village (c. 12th century) is
fundamentally different than identity in the virtual village
(c. 21st century)
 When mobility is limited, establishing identity is relatively
easy
 As mobility increases, establishing identity becomes both
more difficult, more important, and potentially more useful
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3. How Is Identity Established?
 First-hand Recognition
• This is the trivial case
• Limited utility outside of very constrained contexts, by its very nature
 Second-Hand Recognition (aka “Introduction”)
• A mutually trusted third party is necessary to make the introduction
• Second-hand recognition becomes first-hand recognition
 You know me, you know her, but does she know me?
• Identity relationships are not inherently transitive
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4. Increased Mobility Requires Credentials
 Reputation could be passed on, one hop at a time.
Someone had to vouch for you, or give you a reference
 As we travelled farther, we needed credentials
 As we did more things, and needed to establish our
identities for different purposes, we needed more
credentials
 Today, we travel farther than ever, both physically and
virtually; we do more things than ever.
Copyright © 2006, PalmSource, Inc. All rights reserved.

5. Third-Hand Recognition…
 …otherwise known as “credentials”
• Again, a trusted third party (aka “an authority”) is required
• A business card is not a credential; lose your wallet and see for
yourself!
• My driver’s license is not generally helpful in Nepal…
 Credentials need to be authenticatable
• The authority can (hopefully) validate credentials, but this is not
always practical…
• Challenges and responses…
Copyright © 2006, PalmSource, Inc. All rights reserved.

6. Some Different Kinds of Credentials
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7. A Quick Digression…
 The GSM/SIM system is the most widespread identity
management infrastucture ever created…
• More than 1.7 billion subscribers in over 200 countries at the end
of 2005
• There are more countries with GSM systems than there are in the
United Nations!
• There are more countries with GSM systems than there are with
McDonalds!
 UMTS/USIM will make even greater functionality available
Copyright © 2006, PalmSource, Inc. All rights reserved.

8. Who I Am Depends on What’s Going On
 A particular “identity”, i.e. a given credential, is only meaningful in a
given context and domain
• Driver’s license at the airport ticket counter…? Okay!
• Passport at the airport ticket counter…? Okay!
• Driver’s license at the roadside…? Okay!
• Passport at the roadside…? Not okay.
• Passport at immigration…? Okay!
• Driver’s license at immigration…? Not okay.
 Potentially, my mobile device can encompass all these credentials
and more…
Copyright © 2006, PalmSource, Inc. All rights reserved.

9. Authentication
 Authentication reliably associates an actual human being (i.e. a
physical identity) with a digital identity
• Via something you know (e.g. a password)
• Via something you have (e.g. a token)
• Via something you are (e.g. biometrics)
 Strong authentication requires multiple factors
• My passport functions as a two-factor authentication: a physical token
with an embedded “biometric device”…
 As we do more with our mobile devices—i.e. as our mobile devices
hold more, and more sensitive information about us—the need to
authenticate increases
Copyright © 2006, PalmSource, Inc. All rights reserved.

10. Another Brief Digression
• The hanko: something you have… ==
• Hanko design requires research; they need to be
unique, even for common names
– 430,000 people in Japan have the last name “Sato”
• This is why archaic scripts, such as tensho (i.e. “seal
script”) are used for this sort of thing…
• Since the hanko is only a single-factor authentication
scheme, and since there are no protections against
copying, physical or digital, hanko counterfeit is a
growing and serious problem in Japan
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11. One Response…
 Mitsubishi Pencil Co. introduced the “Dial Bank Hanko”…
 Two eight-position dials alter the arrangement of the
pattern on the outer rings
• 64 possibilities…
• Acceptance has been…slow
Copyright © 2006, PalmSource, Inc. All rights reserved.

12. Who I Am Depends on Who You Are
 Identity is about relationship and access
• My work “identity”: access to my corporate network, servers, etc.
• My cellphone “identity”: access to my provider’s network
• My Google “identity”: access to email, etc.
• My Amazon “identity”: access to my recommendations, past
orders, etc.
 Managing a multiplicity of “identities” becomes
increasingly difficult…
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13. Multiple Identity Disorder…?
 Even in a given context, one can have multiple identities.
At work I have:
• An email “identity”
• A source code management system “identity”
• A bug tracking system “identity”
• A payroll system “identity”
• And several others…
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14. Names
 Names abstract multiple identities, multiple kinds of identity, and the
attributes of identity
• My web page changes, but the URL remains the same…
 Names simplify access to identity
• “www.google.com” or 72.14.205.99 or 72.14.205.104 or…?
 For a name to be useful, you need access to the information it
abstracts
• This is the function of “a directory”
• LDAP is one example: I can access all my work “identities” through a
single password…
Copyright © 2006, PalmSource, Inc. All rights reserved.

15. Partial Identities
 Mary has  Boyfriend Bob sees
• A Social Security • A Social Security
number number
• An auto insurance • An auto insurance policy
policy number number
• A work phone • A work phone
• A personal mobile • A personal mobile
phone phone
• A diary • A diary
Copyright © 2006, PalmSource, Inc. All rights reserved.

16. Partial Identities
 Mary has  Mary’s employer sees
• A Social Security • A Social Security
number number
• An auto insurance • An auto insurance policy
policy number number
• A work phone • A work phone
• A personal mobile • A personal mobile
phone phone
• A diary • A diary
Copyright © 2006, PalmSource, Inc. All rights reserved.

17. Why Partial Identities?
 In a secure system, access to resources is based on the “principle of
least privilege”
 Similarly, in identity management, access to information should be
based on the “principle of data economy”
 Transactions should be
• Unobservable: they directly reveal no information about the parties
involved
• Untraceable: no framing information is usable to identify the parties
involved
• Unlinkable: no two transactions can be associated with one another
 Anonymity should be the baseline…
Copyright © 2006, PalmSource, Inc. All rights reserved.

18. “But wait, there’s more!”
 As mobile devices, and the systems supporting them
become more capable, the information which can be
incorporated into one or more of our identities expands:
• Location
• Location history
• Friends and contacts
• Preferences
• Buying habits
• Etc…
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19. Expanded Identities, Expanded Services
 Based on my preferences, location and time of day, the content of my
personal mobile “portal” can be customized…
• Most likely in coordination with service-providing partners
 “I’m away from home, it’s lunch time in this time zone, and I like
ramen…”
• I like places with counters better than places with tables…
• I especially like Sapporo-style miso ramen…
• Etc., etc…
Copyright © 2006, PalmSource, Inc. All rights reserved.

20. A Sample Enhanced Transaction
 I choose a participating restaurant from the selection on
my phone’s customized portal…
 A token (a credential) is transferred to my phone by the
service provider…
 When I go to the (physical) restaurant, my phone
transfers the token back…
• I get a discount on my ramen
• The service provider is paid a “finder’s fee” by the ramen-ya
• The service provider pays a participation fee to the network
operator
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21. A Couple of Points…
 My mobile operator doesn’t need to know I like ramen,
only that I received a token (of some sort) that I might
redeem…
 The ramen-ya doesn’t need to know anything about me
(other than that I’ve presented them with a verifiably valid
discount token)
Copyright © 2006, PalmSource, Inc. All rights reserved.

22. More Scenarios…
 Based on my location and my DVD-buying habits…
• The service provider recommends a movie to me…
• I buy an “e-movie-ticket” through my mobile device…
• My mobile operator passes the payment to the theater…
• The theater pays the service provider…
 The service provider is able to leverage the mobile
operator’s billing infrastructure!
 My phone can be my wallet—eCash experiments in
Tokyo…
Copyright © 2006, PalmSource, Inc. All rights reserved.

23. Some Proposed Definitions
 Mobile Identity = Data + Policies regarding the use of that
data
 Mobile Identity is a set of claims a “digital subject” makes
regarding itself
Copyright © 2006, PalmSource, Inc. All rights reserved.

24. Challenges
 Security is not generally a goal of users, they don’t view it
as making them more productive…
 Users underestimate the consequences of insufficient
security
• Thus, they are not willing to invest a lot of effort in order to learn
how to use security mechanisms…
Copyright © 2006, PalmSource, Inc. All rights reserved.

25. What’s Needed Here…?
 User-friendly interfaces need to be developed for the non-
expert to prevent unintentional misuse
• Different “partial identities” for different purposes
 Verifiable linkage between real and digital identity on
user’s device is critical to prevent impersonation
 Published identifying data—both personal and device
characteristics—must be protected against misuse
Copyright © 2006, PalmSource, Inc. All rights reserved.

26. What Are We Doing?
 The ACCESS Linux Platform provides facilities which can
be leveraged for on-device identity management
• A flexible, policy-driven security infrastructure
• Support for a variety of authentication schemes through Linux’s
PAM infrastructure
• Certificate management services
• SIM tool kit
• Vaulting services
Copyright © 2006, PalmSource, Inc. All rights reserved.

27. Some Recommended Reading
 The Consortium of the Future of Identity in the Information
Society (FIDIS): www.fidis.net
• D3.3: A Study on Mobile Identity Management
• D11.1: Towards a Taxonomy of Mobility and Identity
 Digital Identity, J. Philip Windley, O’Reilly Books
Copyright © 2006, PalmSource, Inc. All rights reserved.

28. That’s all, folks!
Thanks!
Copyright © 2006, PalmSource, Inc. All rights reserved. 28