Title
Brandt’s fully private auction protocol revisited
Abstract
Auctions have a long history, having been recorded as early as 500 B.C. [Auction Theory, Academic Press, San Diego, USA, 2002]. Nowadays, electronic auctions have been a great success and are increasingly used in various applications, including high performance computing [Concurrency and Computation: Practice and Experience 14(13-15) (2002), 1507-1542]. Many cryptographic protocols have been proposed to address the various security requirements of these electronic transactions, in particular to ensure privacy. Brandt [International Journal of Information Security 5 (2006), 201-216] developed a protocol that computes the winner using homomorphic operations on a distributed ElGamal encryption of the bids. He claimed that it ensures full privacy of the bidders, i.e. no information apart from the winner and the winning price is leaked. We first show that this protocol - when using malleable interactive zero-knowledge proofs - is vulnerable to attacks by dishonest bidders. Such bidders can manipulate the publicly available data in a way that allows the seller to deduce all participants' bids. We provide an efficient parallelized implementation of the protocol and the attack to show its practicality. Additionally we discuss some issues with verifiability as well as attacks on non-repudiation, fairness and the privacy of individual bidders exploiting authentication problems.
Year
DOI
Venue
2015
10.3233/JCS-150535
JOURNAL OF COMPUTER SECURITY
Keywords
Field
DocType
Anonymity,applied cryptography,cryptographic protocols,privacy-enhancing technology
Homomorphic encryption,Authentication,Cryptographic protocol,Protocol analysis,Computer science,Computer security,Common value auction,ElGamal encryption,Anonymity,Zero-knowledge proof
Journal
Volume
Issue
ISSN
23
5
0926-227X
Citations 
PageRank 
References 
2
0.37
19
Authors
3
Name
Order
Citations
PageRank
Jannik Dreier112113.70
Jean-Guillaume Dumas242868.48
Pascal Lafourcade356958.37