Anonymity - Background Prof. Newman, instructor CSE-E (don’t leave message) Office Hours (tentative): 10-noon TR - subject: Anon...

Topics Defining anonymity Defining privacy Need for anonymity Threats to anonymity and privacy Mechanisms to provide anonymity Applications of anonymity technology

Reading Read Pfitzman & Waidner Read Chaum Mix paper Start discussion of these Friday Reading list (approximate) on web page

Outline Course Outline – what is this subject? Projects and papers Policies

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 Anonymity - Beginnings

Exercise Take 2 minutes to think about anonymity. Answer these questions in writing: What is anonymity? How is it related to privacy? Give examples of need for anonymity (aiming at volume here) Get into groups of 2-3 and share your answers Try to arrive at a joint definition or agree to disagree Add to your list of examples Share your responses with the class

What is Anonymity Literally, lacking a name (a + onyma) Unidentifiability Inability to attribute artifact or actions Related to privacy - how?

Topics Defining anonymity Defining privacy Need for anonymity Threats to anonymity and privacy Mechanisms to provide anonymity Applications of anonymity technology

Exercise Take a minute or two to define privacy Share with your neighbor(s) Share with the class

What is Privacy? Ability of an entity to control its own space Physical space Bodily space Data space Communication space What else?

Exercise What are examples of privacy in these spaces? Physical space Bodily space Data space Communication space What other spaces can you think of?

Privacy Spaces Physical space: invasion, paparazzi, location (GPS) Bodily space: medical consent, battery Data space: identity, activity, status, records Communication space: , Internet privacy, correspondents, phone #, address, stalking, harassment Overlap in spaces (e.g., location)

Topics Defining anonymity Defining privacy Need for anonymity Threats to anonymity and privacy Mechanisms to provide anonymity Applications of anonymity technology

Need for Privacy/Anonymity Planning/execution in competition Fundamental right – voting, celebrities Philosophical necessity (free will) Restarting when past can cripple Statutory requirements (HIPAA, FISMA) Liability issues – data release Freedom/survival in repressive environments Increasing pressure from technologies

Privacy/Anonymity Threats Available surveillance technology Identification technology Increasing use of databases Data mining Identity theft Increasing requirements for I&A Increasing governmental desire for surveillance

Surveillance Facts 1.5 million CCTV cameras installed in UK post 911 – Londoner on camera ~300 times a day 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

Homework Count number of video cameras you encounter all day for one day. Record locations, submit when Canvas up. Tally total, share total with class Friday.

Data Reidentification 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 What are legitmate limitations on anonymity? Write down 1-2 of these Share with neighbor Share with class

Limitations on Anonymity Accountability Legal/criminal issues Social expectations Competing need for trust Others?

Forms of Anonymity Traffic Analysis Prevention Sender, Recipient, Message Anonymity Voter Anonymity Pseudonymity Revokable anonymity Data anonymity

Anonymity Mechanisms Cryptography Steganography Traffic Analysis Prevention (TAP) Mixes, crowds Data sanitization/scrubbing k-anonymity