what can a click really reveal? the utility and privacy ... · conclusion • we precisely measure...
TRANSCRIPT
What Can a Click Really Reveal? The Utility and Privacy Effects of a Click
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Rachid Guerraoui Anne-Marie Kermarrec
Mahsa Taziki
What happens when you access online services?
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Clicks
Recommendations
Utility
Privacy
Trade-off?Always
Outline• Quantifying the utility and privacy effects of a click
- How to measure utility? - How to measure privacy? - How utility and privacy are connected?
• The Click-advisor diagram
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Outline• Quantifying the utility and privacy effects of a click
- How to measure utility? - How to measure privacy? - How utility and privacy are connected?
• The Click-advisor diagram
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How to measure utility?
• A commonality-based utility measure (Commonality of a user profile)
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Utility of a click
Commonality
=
- +
Commonality - Example
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Commonality = 0
Commonality = 0.375
Commonality in Perspective
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Outline• Quantifying the utility and privacy effects of a click
- How to measure utility? - How to measure privacy? - How utility and privacy are connected?
• The Click-advisor diagram
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Disclosure risk of a click
How to measure privacy?
• An entropy-based privacy measure (Disclosure degree of a user profile)
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Disclosure Degree
=
- +
Disclosure Degree - Example
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Commonality = 0
Commonality = 0.375 = 0.9
= 1.2
Disclosure Degree in Perspective
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Outline• Quantifying the utility and privacy effects of a click
- How to measure utility? - How to measure privacy? - How utility and privacy are connected?
• The Click-advisor diagram
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• Clicks that induce a trade-off between utility and privacy: 78.40 %
• Clicks that improve both utility and privacy: 5.12 %
• Clicks that improves neither utility nor privacy: 16.48 %
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How utility and privacy are connected?
Example: Movielens 100K dataset
Different Effects of Clicks
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Outline• Quantifying the utility and privacy effects of a click
- How to measure utility? - How to measure privacy? - How utility and privacy are connected?
• The Click-advisor diagram
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Outline• Quantifying the utility and privacy effects of a click
- How to measure utility? - How to measure privacy? - How utility and privacy are connected?
• The Click-advisor diagram - The zone of a click
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The Zone of a Click
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Safe
Deleterious
Dangerous
Trade-off
Trade-off
Outline• Quantifying the utility and privacy effects of a click
- How to measure utility? - How to measure privacy? - How utility and privacy are connected?
• Click-advisor diagram - The zone of a click - The click-advisor diagram
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Recommendations
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Toy Story
Greenberg
The Switch
Pre-clicks
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Toy Story
Greenberg
The Switch
The Click-advisor Diagram
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TToy Story
Greenberg
The Switch
Outline• Quantifying the utility and privacy effects of a click
- How to measure utility? - How to measure privacy? - How utility and privacy are connected?
• Click-advisor diagram - The zone of a click - The click-advisor diagram - The user actions
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The User Actions
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TToy Story
Greenberg
The Switch
You like “Toy Story”. This click is in a safe zone. So, it improves both utility and privacy for you. Do you want to:
Outline• Quantifying the utility and privacy effects of a click
- How to measure utility? - How to measure privacy? - How utility and privacy are connected?
• Click-advisor diagram - The zone of a click - The click-advisor diagram - The user actions - The clicking game
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The Clicking Game
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The Clicking Game
• Reward function
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The Clicking Game
• Reward function
• Users actions
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Confirm / Change / Cancel
The Clicking Game
• Reward function
• User actions
• Clicking strategies
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Clicking Strategies
• Basic: confirms all the pre-clicks.
• Careful: confirms the safe and trade-off pre-clicks; otherwise, cancels.
• Smart: confirms the safe and trade-off pre-clicks;
cancels the deleterious pre-clicks;
changes the dangerous pre-clicks.
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Clicking Game (1)
All users playing smart is a Nash equilibrium, i.e., playing the smart strategy maximizes the reward function for a user u, if every user other than u plays smart.
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Clicking Game (2)
The overall average of the recommender utility for all users playing the smart strategy is the same as the case where users click on items based on their real preferences. However, with regard to privacy, the smart strategy provides better privacy compared to the basic strategy.
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Conclusion
• We precisely measure the utility and privacy effects of a click.
• We show that there is not always a trade-off between utility and privacy.
• The click-advisor diagram makes users aware of the utility and privacy effects of their clicks.
• Consulting the click-advisor, the users can adopt a clicking strategy to improve their privacy without decreasing the overall recommender utility.
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