1. Privacy Protection for Social Network Services

2. outline
Privacy issues with online social networks (or social network services)
Research challenges
Two sample approaches
Privacy wizard
Privacy score
Summary

3. Rapid growth of SNS - Facebook

4. situations SNS data are profitable to SNS providers
SNS utilities are valuable to users, SNS providers, and App Develops
All SN data are sensitive
Different users may have different privacy requirements. 
There are many profile items, each of which may require different protection levels. 
Many users are not aware of privacy risk
Contents might be generated collaboratively. 

5. Research issues Outsourcing SN data (discussed) Users’ privacy setting
Privacy preserving use of SN data (SNS providers/app developers)
Tradeoff between privacy and utility

6. Focus on two problems
Helping user set appropriate privacy levels for many profile items
Evaluate the privacy risk

7. Automatic Privacy Setting
Problems
Average users don’t know how to express their privacy preferences.
What does it mean for specific privacy settings.
Solutions
Design automatic tools to do this task.
Challenges
Solicit input from user – as easy and straightforward as possible.
Adapt to changes.

10. Privacy Wizard
Using machine learning algorithms to train a privacy preference selector for profile items.
Training data: existing users’ privacy settings, biographical information
Input: the user’s bio info, output: the setting for a specific item
Assumption: people with similar bio info may have similar privacy preference.

11. Observations Such models might exist Accuracy of the models
Friends may share similar opinions on privacy setting
Access control is defined on groups?
Accuracy of the models
The amount of training data
Properly group users

12. The privacy wizard

13. Comments on Privacy Wizard
Strengths:
One of the first attempts to answer the question of automatic privacy settings.
Model can work for controlling private profile items.
problems
Difficult on dynamic contents, such as photos and wall posts.
Assumptions might not hold – privacy setting is a very personalized choice