Title
Pay to Win: Cheap, Cross-Chain Bribing Attacks on PoW Cryptocurrencies
Abstract
In this paper we extend the attack landscape of bribing attacks on cryptocurrencies by presenting a new method, which we call Pay-To-Win (P2W). To the best of our knowledge, it is the first approach capable of facilitating double-spend collusion across different blockchains. Moreover, our technique can also be used to specifically incentivize transaction exclusion or (re)ordering. For our construction we rely on smart contracts to render the payment and receipt of bribes trustless for the briber as well as the bribee. Attacks using our approach are operated and financed out-of-band i.e., on a funding cryptocurrency, while the consequences are induced in a different target cryptocurrency. Hereby, the main requirement is that smart contracts on the funding cryptocurrency are able to verify consensus rules of the target. For a concrete instantiation of our P2W method, we choose Bitcoin as a target and Ethereum as a funding cryptocurrency. Our P2W method is designed in a way that reimburses collaborators even in the case of an unsuccessful attack. Interestingly, this actually renders our approach approximately one order of magnitude cheaper than comparable bribing techniques (e.g., the whale attack). We demonstrate the technical feasibility of P2W attacks through publishing all relevant artifacts of this paper, ranging from calculations of success probabilities to a fully functional proof-of-concept implementation, consisting of an Ethereum smart contract and a Python client.
Year
DOI
Venue
2021
10.1007/978-3-662-63958-0_39
FINANCIAL CRYPTOGRAPHY AND DATA SECURITY, FC 2021
Keywords
DocType
Volume
Algorithmic incentive manipulation, Bribing, Smart contracts, Ethereum, Bitcoin
Conference
12676
ISSN
Citations 
PageRank 
0302-9743
0
0.34
References 
Authors
0
8
Name
Order
Citations
PageRank
Aljosha Judmayer123.76
Nicholas Stifter223.76
Alexei Zamyatin3176.86
Itay Tsabary431.76
Ittay Eyal530426.11
Peter Gazi66510.14
Sarah Meiklejohn732323.67
Edgar Weippl82010.62