Download Lecture 2c - Getting a grip on anonymity

Anonymity - Background
R. Newman
Anonymity - Beginnings
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Early (pre-computer) uses for social reasons
(ability to act more freely, have work accepted
without prejudice, etc.)
Traffic analysis an issue prior to computers
(e.g., Bodyguard of Lies)
Computer TAP solvable with cryptography
With public-key cryptography, theoretical
possibility for anonymity and pseudonymity
Topics
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Defining anonymity
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Defining privacy
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Need for anonymity
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Threats to anonymity and privacy
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Mechanisms to provide anonymity
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Applications of anonymity technology
Privacy/Anonymity Threats
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Available surveillance technology
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Identification technology
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Increasing use of databases
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Data mining
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Identity theft
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Increasing requirements for I&A
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Increasing governmental desire for surveillance
Surveillance Facts
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1.5 million CCTV cameras installed in UK post
911 – Londoner on camera ~300 times a day
http://epic.org/privacy/surveillance/
Face recognition software used in Tampa for
Superbowl
5000 public surveillance cameras known in DC
Home and work zipcodes give identity in 5% of
cases in US http://33bits.org/tag/anonymity/
Homework
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Count number of video cameras you encounter
all day for one day.
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Record locations, submit when Canvas up.
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Tally total, share total with class Friday.
Data Reidentification
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Even ”scrubbed” data can be re-identified
Characteristics within the data (e.g., word
usage in documents)
Intersection attacks on k-anonymized database
set releases
Use of known outside data in combination with
released data
Data mining – higher dimensional space gives
greater specificity!
Exercise
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What are legitmate limitations on anonymity?
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Write down 1-2 of these
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Share with neighbor
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Share with class
Limitations on Anonymity
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Accountability
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Legal/criminal issues
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Social expectations
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Competing need for trust
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Others?
Forms of Anonymity
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Traffic Analysis Prevention
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Sender, Recipient, Message Anonymity
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Voter Anonymity
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Pseudonymity
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Revokable anonymity
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Data anonymity
Topics
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Defining anonymity
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Need for anonymity
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Defining privacy
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Threats to anonymity and privacy
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Mechanisms to provide anonymity
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Applications of anonymity technology
Anonymity Mechanisms
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Cryptography
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Steganography
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Traffic Analysis Prevention (TAP)
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Mixes, crowds
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Data sanitization/scrubbing
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k-anonymity