Cryptology ePrint Archive: Report 2016/464
Beaver: A Decentralized Anonymous Marketplace with Secure Reputation
Kyle Soska and Albert Kwon and Nicolas Christin and Srinivas Devadas
Abstract: Amid growing concerns of government surveillance
and corporate data sharing, web users increasingly demand tools
for preserving their privacy without placing trust in a third
party. Unfortunately, existing centralized reputation systems need
to be trusted for either privacy, correctness, or both. Existing
decentralized approaches, on the other hand, are either vulnerable to Sybil attacks, present inconsistent views of the network,
or leak critical information about the actions of their users.
In this paper, we present Beaver, a decentralized anonymous
marketplace that is resistant against Sybil attacks on vendor
reputation, while preserving user anonymity. Beaver allows its
participants to enjoy open enrollment, and provides every user
with the same global view of the reputation of other users through
public ledger based consensus. Various cryptographic primitives
allow Beaver to offer high levels of usability and practicality,
along with strong anonymity guarantees. Operations such as
creating a listing, purchasing an item, and leaving feedback take
just milliseconds to compute and require generating just a few
kilobytes of state while often constructing convenient anonymity
sets of hundreds of transactions.
Category / Keywords: applications / reputation systems; anonymity; e-commerce; consensus
Date: received 12 May 2016, last revised 20 Aug 2016
Contact author: ksoska at cmu edu
Available format(s): PDF | BibTeX Citation
Version: 20160820:232252 (All versions of this report)
Short URL: ia.cr/2016/464
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