Economic Location-Based Services, Privacy and the Relationship to Identity

Lothar FritschLothar.Fritsch@M-Lehrstuhl.de

Lehrstuhl für M-Commerce& Mehrseitige Sicherheit

Johann Wolfgang Goethe-Universität

Frankfurt am Main

22 – Jan - 2005

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LBS Business Scenarios

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Privacy threats posed by LBS

1. A subject might find himself or herself in the situation to justify the whereabouts stored in someone else’s systems. This is an essential issue concerning control over one’s personal data (just like address trade, or consumer profiling).

2. An anonymous subject’s identity can be learned by observing its frequently-used locations (where one stays every night is one’s home).

3. A subject’s context can be guessed by observing location combined with geographic metadata (e.g. about office location, business district, sport locations, red light area).

4. The proximity to other subjects can reveal personal relationships.

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Dimension of ID

Gary T. Marx proposes seven types of ID relevant information, or „attributes“, as Hansen/Pfitzmann call ID information.• Legal Name• Location / reachability• Publicly intermediated

pseudonyms• Secret pseudonyms

• Appearance and Behaviour patterns• Social categorization• Possession of knowledge

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Problem in ID attributes: Mobility

ID follwoing the Hansen/Pfitzmann Definition:Identifiability is the possibility of being individualized within a set of subjects, the identifiability set. (…) An identity is any subset of attributes of an individual which uniquely characterizes this individual within any set of individuals. So usually there is no such thing as “the identity”, but several of them.

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Problem in ID attributes: Mobility

ID_Lothar=(Male,190cm,beard,drinks_beer,Is_In_Riezlern)

But I‘m not always in Riezlern. What happens to my ID when I‘m mobile?

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Problem in ID attributes: Mobility

Do we need the introduction of a „freshness“ timestamp for volatile ID attributes?This would lead to attributes of long-time value, and attributes of temporal value.

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LBS & attributes

LBS obviously need location information.According to Marx, rechability is an important attribute, too.

Beyond these two attributes, IDs for LBS should have as little information as possible.

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Suggestion for LBS IDM

LBS with IDM will need machanisms to:1. Conceal attributes not needed2. Provide location and a few attributes3. Create rechability with anonymitySolutions:1. Should be done with good pseudonymity2. Can be done with selective IDM3. Should be done with anonymous

channels used for communications

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Discussion

Please ask, discuss, critizise, send references :-)