logo资料库

安全多方计算以及密钥共享.pdf

第1页 / 共52页
第2页 / 共52页
第3页 / 共52页
第4页 / 共52页
第5页 / 共52页
第6页 / 共52页
第7页 / 共52页
第8页 / 共52页
资料共52页,剩余部分请下载后查看
Introduction
The problem
Motivation and applications
Basic Terminology
Corrupted parties
Definitions of security
Protocols for Multi-Party Computations
Overview
Passive secure protocol
Active secure protocol
Appendix
Secure Multi-Party Computations Secure Multi-Party Computations An Introduction Christian Zielinski Last updated in 2015 1 / 52
Secure Multi-Party Computations Outline 1 Introduction The problem Motivation and applications 2 Basic Terminology Corrupted parties Definitions of security 3 Protocols for Multi-Party Computations Overview Passive secure protocol Active secure protocol References 2 / 52
Secure Multi-Party Computations Introduction Outline 1 Introduction The problem Motivation and applications 2 Basic Terminology Corrupted parties Definitions of security 3 Protocols for Multi-Party Computations Overview Passive secure protocol Active secure protocol References 3 / 52
Secure Multi-Party Computations Introduction The problem Secure multi-party computations • Consider n parties, with private inputs x1, . . . , xn • They want to compute a function f (x1, . . . , xn) in a secure way • Security means here • Privacy: The respective inputs remain private • Correctness: The output is guaranteed to be correct • Fairness: Each party learns the result • This should even hold when some parties try to cheat • The following presentation is primarily based on Ref. [1, 2] 4 / 52
Secure Multi-Party Computations Introduction The problem Questions at hand • How to carry out computations without revealing the inputs? • How to deal with cheating (corrupted) parties? • How to define security formally? • What is the upper limit of corrupted parties allowed? • How does this bound depend on the assumption made about the attacker? 5 / 52
Secure Multi-Party Computations Introduction Motivation and applications Motivation and applications • Multi-party computations (MPCs) have a wide range of applications • Auctions • Several parties are bidding for a product • Winning party and maximum bid should be determined, without revealing bids of other parties • Electronic voting schemes • Each party votes for a candidate • Only the result is made public, the votes remain secret • Yao’s Millionaires’ Problem, c.f. Ref. [3] • A group of millionaires wants to find out who is the richest • Nobody wants to reveal how wealthy they are 6 / 52
Secure Multi-Party Computations Basic Terminology Outline 1 Introduction The problem Motivation and applications 2 Basic Terminology Corrupted parties Definitions of security 3 Protocols for Multi-Party Computations Overview Passive secure protocol Active secure protocol References 7 / 52
Secure Multi-Party Computations Basic Terminology Corrupted parties Adversaries • To discuss secure MPCs, we have to define security • Hence we have to make assumptions about cheating parties • Typically one models them by considering an adversary • This adversary can take over (corrupt) certain subsets of parties • We assume one adversary, assuming the worst-case scenario of coordinated corrupted parties (monolithic adversary) • We assume that at the beginning of the protocol honest (i.e. not corrupted) parties do not know which parties are corrupted 8 / 52
分享到:
收藏