Formal Verification of e-Auction Protocols

Auctions have a long history, having been recorded as early as 500 B.C.. With the rise of Internet, electronic auctions have been a great success and are increasingly used. Many cryptographic protocols have been proposed to address the various security requirements of these electronic transactions. We propose a formal framework to analyze and verify security properties of e-Auction protocols. We model protocols in the Applied Pi-Calculus and define privacy notions, which include secrecy of bids, anonymity of the participants, receipt-freeness and coercion-resistance. We also discuss fairness, non-repudiation and non-cancellation. Additionally we show on two case studies how these properties can be verified automatically usingProVerif, and discover several attacks

Formal Analysis of E-Cash Protocols

International audienceElectronic cash (e-cash) aims at achieving client privacy at payment, similar to real cash. Several security protocols have been proposed to ensure privacy in e-cash, as well as the necessary unforgery properties. In this paper, we propose a formal framework to define, analyze, and verify security properties of e-cash systems. To this end, we model e-cash systems in the applied π-calculus, and we define two client privacy properties and three properties to prevent forgery. Finally, we apply our definitions to an e-cash protocol from the literature proposed by Chaum et al., which has two variants and a real implementation based on it. Using ProVerif, we demonstrate that our framework is suitable for an automated analysis of this protocol

Publicly Verifiable Auctions with Privacy

Online auctions have a steadily growing market size, creating billions of US dollars in sales value every year. To ensure fairness and auditability while preserving the bidder\u27s privacy is the main challenge of an auction scheme. At the same time, utility driven blockchain technology is picking up the pace, offering transparency and data integrity to many applications. In this paper, we present a blockchain-based first price sealed-bid auction scheme. Our scheme offers privacy and public verifiability. It can be built on any public blockchain, which is leveraged to provide transparency, data integrity, and hence auditability. The inability to double spend on a blockchain is used to prevent bid replay attacks. Moreover, our scheme can achieve non-repudiation for both bidders and the auctioneer without revealing the bids and we encapsulate this concept inside the public verification of the auction. We propose to use ElGamal encryption and Bulletproofs to construct an efficient instantiation of our scheme. We also propose to use recursive zkSNARKs to reduce the number of comparison proofs from $N-1$ to $1$, where $N$ is the number of bidders

Formal Verification of e-Auction protocols

Abstract. Auctions have a long history, having been recorded as early as 500 B.C.. With the rise of Internet, electronic auctions have been a great success and are increasingly used. Many cryptographic protocols have been proposed to address the various security requirements of these electronic transactions. We propose a formal framework to analyze and verify security properties of e-Auction protocols. We model protocols in the Applied Pi-Calculus and define privacy notions, which include secrecy of bids, anonymity of the participants, receiptfreeness and coercion-resistance. We also discuss fairness, non-repudiation and non-cancellation. Additionally we show on two case studies how these properties can be verified automatically using ProVerif, and discover several attacks.