Edinburgh Research Explorer On Trees, Chains and Fast Transactions in the Blockchain
Edinburgh Research Explorer On Trees, Chains and Fast Transactions in the Blockchain
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发表时间：
2017
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通讯作者：
A. Kiayias;Giorgos Panagiotakos
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作者：
A. Kiayias;Giorgos Panagiotakos
. A fundamental open problem in the area of blockchain protocols is whether the Bitcoin protocol is the only solution for building a secure transaction ledger. A recently proposed and widely considered alternative is the GHOST protocol which, notably, was proposed to be at the core of Ethereum as well as other recent proposals for improved Bitcoin-like systems. The GHOST variant is touted as o(cid:27)ering superior performance compared to Bitcoin (potentially o(cid:27)ering block production speed up by a factor of more than 40) without a security loss. Motivated by this, in this work, we study from a provable security point of view the GHOST protocol. 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 uni(cid:28)ed description of the GHOST and Bit-coin protocols, the former of which we extract and formally describe. We then prove that GHOST implements a (cid:16)robust transaction ledger(cid:17) (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.
