Vote-Independence: A Powerful Privacy Notion for Voting Protocols - PowerPoint PPT Presentation

Introduction Intuitive Definitions Formal Definitions Analysis and Case Studies Conclusion Vote-Independence: A Powerful Privacy Notion for Voting Protocols Jannik Dreier, Pascal Lafourcade, Yassine Lakhnech Université Grenoble 1, CNRS, Verimag FPS 2011: May 13, 2011 Jannik Dreier, Pascal Lafourcade, Yassine Lakhnech Vote-Independence

Introduction Intuitive Definitions Formal Definitions Analysis and Case Studies Conclusion Plan 1 Introduction What is electronic voting? An Attack on Privacy in Helios 2 Intuitive Definitions Privacy Vote-Independence 3 Formal Definitions 4 Analysis and Case Studies 5 Conclusion Jannik Dreier, Pascal Lafourcade, Yassine Lakhnech Vote-Independence

Introduction Intuitive Definitions What is electronic voting? Formal Definitions An Attack on Privacy in Helios Analysis and Case Studies Conclusion Plan 1 Introduction What is electronic voting? An Attack on Privacy in Helios 2 Intuitive Definitions Privacy Vote-Independence 3 Formal Definitions 4 Analysis and Case Studies 5 Conclusion Jannik Dreier, Pascal Lafourcade, Yassine Lakhnech Vote-Independence

Introduction Intuitive Definitions What is electronic voting? Formal Definitions An Attack on Privacy in Helios Analysis and Case Studies Conclusion Plan 1 Introduction What is electronic voting? An Attack on Privacy in Helios 2 Intuitive Definitions Privacy Vote-Independence 3 Formal Definitions 4 Analysis and Case Studies 5 Conclusion Jannik Dreier, Pascal Lafourcade, Yassine Lakhnech Vote-Independence

Introduction Intuitive Definitions What is electronic voting? Formal Definitions An Attack on Privacy in Helios Analysis and Case Studies Conclusion Voting machines are not a recent technology They have been in use in the US for over 100 years! Jannik Dreier, Pascal Lafourcade, Yassine Lakhnech Vote-Independence

Introduction Intuitive Definitions What is electronic voting? Formal Definitions An Attack on Privacy in Helios Analysis and Case Studies Conclusion Electronic voting machines. . . . . . are used all over the world Jannik Dreier, Pascal Lafourcade, Yassine Lakhnech Vote-Independence

Introduction Intuitive Definitions What is electronic voting? Formal Definitions An Attack on Privacy in Helios Analysis and Case Studies Conclusion Internet voting Available in Estonia France Switzerland . . . Jannik Dreier, Pascal Lafourcade, Yassine Lakhnech Vote-Independence

Introduction Intuitive Definitions What is electronic voting? Formal Definitions An Attack on Privacy in Helios Analysis and Case Studies Conclusion Security Requirements Fairness Individual Verifiability Eligibility Universal Verifiability Security Requirements Privacy Robustness Receipt-Freeness Coercion-Resistance Jannik Dreier, Pascal Lafourcade, Yassine Lakhnech Vote-Independence

Introduction Intuitive Definitions What is electronic voting? Formal Definitions An Attack on Privacy in Helios Analysis and Case Studies Conclusion Security Requirements Fairness Individual Verifiability Eligibility Universal Verifiability Security Requirements Privacy Robustness Receipt-Freeness Coercion-Resistance Jannik Dreier, Pascal Lafourcade, Yassine Lakhnech Vote-Independence

Introduction Intuitive Definitions What is electronic voting? Formal Definitions An Attack on Privacy in Helios Analysis and Case Studies Conclusion Plan 1 Introduction What is electronic voting? An Attack on Privacy in Helios 2 Intuitive Definitions Privacy Vote-Independence 3 Formal Definitions 4 Analysis and Case Studies 5 Conclusion Jannik Dreier, Pascal Lafourcade, Yassine Lakhnech Vote-Independence

Introduction Intuitive Definitions What is electronic voting? Formal Definitions An Attack on Privacy in Helios Analysis and Case Studies Conclusion Attack on Privacy in Helios [ ? ] Helios [ ? ] is a web based open-source voting system based on homomorphic encryption. Server Alice A Bob B =A,B Jannik Dreier, Pascal Lafourcade, Yassine Lakhnech Vote-Independence

Introduction Intuitive Definitions What is electronic voting? Formal Definitions An Attack on Privacy in Helios Analysis and Case Studies Conclusion Attack on Privacy in Helios [ ? ] Helios [ ? ] is a web based open-source voting system based on homomorphic encryption. Server Alice A A Bob B =A,B Jannik Dreier, Pascal Lafourcade, Yassine Lakhnech Vote-Independence

Introduction Intuitive Definitions What is electronic voting? Formal Definitions An Attack on Privacy in Helios Analysis and Case Studies Conclusion Attack on Privacy in Helios [ ? ] Helios [ ? ] is a web based open-source voting system based on homomorphic encryption. Server Alice A A Bob B B =A,B Jannik Dreier, Pascal Lafourcade, Yassine Lakhnech Vote-Independence

Introduction Intuitive Definitions What is electronic voting? Formal Definitions An Attack on Privacy in Helios Analysis and Case Studies Conclusion Attack on Privacy in Helios [ ? ] Helios [ ? ] is a web based open-source voting system based on homomorphic encryption. Server Alice A A + Bob B B =A,B Jannik Dreier, Pascal Lafourcade, Yassine Lakhnech Vote-Independence

Introduction Intuitive Definitions What is electronic voting? Formal Definitions An Attack on Privacy in Helios Analysis and Case Studies Conclusion Attack on Privacy in Helios [ ? ] Eve can attack Alice’s privacy by copying her vote: Server Alice A Eve Bob B =A,A,B To prevent this attack, we have to enforce Vote-Independence . Jannik Dreier, Pascal Lafourcade, Yassine Lakhnech Vote-Independence

Introduction Intuitive Definitions What is electronic voting? Formal Definitions An Attack on Privacy in Helios Analysis and Case Studies Conclusion Attack on Privacy in Helios [ ? ] Eve can attack Alice’s privacy by copying her vote: Server Alice A A Eve Bob B =A,A,B To prevent this attack, we have to enforce Vote-Independence . Jannik Dreier, Pascal Lafourcade, Yassine Lakhnech Vote-Independence

Introduction Intuitive Definitions What is electronic voting? Formal Definitions An Attack on Privacy in Helios Analysis and Case Studies Conclusion Attack on Privacy in Helios [ ? ] Eve can attack Alice’s privacy by copying her vote: Server Alice A A Eve Bob B B =A,A,B To prevent this attack, we have to enforce Vote-Independence . Jannik Dreier, Pascal Lafourcade, Yassine Lakhnech Vote-Independence

Introduction Intuitive Definitions What is electronic voting? Formal Definitions An Attack on Privacy in Helios Analysis and Case Studies Conclusion Attack on Privacy in Helios [ ? ] Eve can attack Alice’s privacy by copying her vote: Server Alice A A A Eve Bob B B =A,A,B To prevent this attack, we have to enforce Vote-Independence . Jannik Dreier, Pascal Lafourcade, Yassine Lakhnech Vote-Independence

Introduction Intuitive Definitions What is electronic voting? Formal Definitions An Attack on Privacy in Helios Analysis and Case Studies Conclusion Attack on Privacy in Helios [ ? ] Eve can attack Alice’s privacy by copying her vote: Server Alice A A A Eve Bob B B A =A,A,B To prevent this attack, we have to enforce Vote-Independence . Jannik Dreier, Pascal Lafourcade, Yassine Lakhnech Vote-Independence

Introduction Intuitive Definitions What is electronic voting? Formal Definitions An Attack on Privacy in Helios Analysis and Case Studies Conclusion Attack on Privacy in Helios [ ? ] Eve can attack Alice’s privacy by copying her vote: Server Alice A A + A Eve Bob B B + A =A,A,B To prevent this attack, we have to enforce Vote-Independence . Jannik Dreier, Pascal Lafourcade, Yassine Lakhnech Vote-Independence

Introduction Intuitive Definitions Privacy Formal Definitions Vote-Independence Analysis and Case Studies Conclusion Plan 1 Introduction What is electronic voting? An Attack on Privacy in Helios 2 Intuitive Definitions Privacy Vote-Independence 3 Formal Definitions 4 Analysis and Case Studies 5 Conclusion Jannik Dreier, Pascal Lafourcade, Yassine Lakhnech Vote-Independence

Introduction Intuitive Definitions Privacy Formal Definitions Vote-Independence Analysis and Case Studies Conclusion Plan 1 Introduction What is electronic voting? An Attack on Privacy in Helios 2 Intuitive Definitions Privacy Vote-Independence 3 Formal Definitions 4 Analysis and Case Studies 5 Conclusion Jannik Dreier, Pascal Lafourcade, Yassine Lakhnech Vote-Independence

Introduction Intuitive Definitions Privacy Formal Definitions Vote-Independence Analysis and Case Studies Conclusion Defining Vote-Privacy [ ? ] Main idea: Observational equivalence between two situations. Alice Bob Vote A B ≈ l Vote B A Jannik Dreier, Pascal Lafourcade, Yassine Lakhnech Vote-Independence

Introduction Intuitive Definitions Privacy Formal Definitions Vote-Independence Analysis and Case Studies Conclusion Defining Receipt-Freeness [ ? ] Again: Observational equivalence between two situations, but Alice tries to create a receipt or a fake. Mallory Alice Bob Secret Data A B ≈ l Fake Data B A Jannik Dreier, Pascal Lafourcade, Yassine Lakhnech Vote-Independence