We introduce a new formal framework for the analysis of blockchain protocols that relies on trees (rather than chains) and we showcase the power of the framework by providing a unified description of the \GHOST and Bitcoin protocols, the former of which we extract and formally describe. We then prove that \GHOST implements a ``robust transaction ledger'' (i.e., possesses liveness and persistence) and hence it is a provably secure alternative to Bitcoin; moreover, our bound for the liveness parameter is superior to that proven for the bitcoin backbone in line with the original expectation for \GHOST. Our proof follows a novel methodology for establishing that \GHOST is a robust transaction ledger compared to previous works, which may be of independent interest and can be applicable to other blockchain variants.
Category / Keywords: cryptographic protocols / Bitcoin, GHOST, confirmation time, blockchain, robust public transaction ledger, security Date: received 1 Jun 2016, last revised 5 Jul 2017 Contact author: g panagiotakos at di uoa gr Available format(s): PDF | BibTeX Citation Note: Found a mistake in the liveness attack. Version: 20170705:140604 (All versions of this report) Short URL: ia.cr/2016/545 Discussion forum: Show discussion | Start new discussion