In this paper, we close this gap by proposing the first framework for defining and analyzing the security of general distributed ledgers, with an ideal distributed ledger functionality, called $\mathcal{F}_\text{ledger}$, at the core of our contribution. This functionality covers not only classical blockchains but also non-blockchain distributed ledgers in a unified way.
To illustrate $\mathcal{F}_\text{ledger}$, we first show that the prominent ideal blockchain functionalities $\mathcal{G}_\text{ledger}$ and $\mathcal{G}_\text{PL}$ realize (suitable instantiations of) $\mathcal{F}_\text{ledger}$, which precisely captures their security properties. This immediately implies that their respective implementations, including Bitcoin, Ouroboros Genesis, and Ouroboros Crypsinous, realize $\mathcal{F}_\text{ledger}$ as well. Secondly, we demonstrate that $\mathcal{F}_\text{ledger}$ is capable of precisely modeling also non-blockchain distributed ledgers by performing the first formal security analysis of such a distributed ledger, namely the prominent Corda protocol. Due to the wide spread use of Corda in the industry, in particular the financial sector, this analysis is of independent interest.
These results also illustrate that $\mathcal{F}_\text{ledger}$ not just generalizes the modular treatment of blockchains to distributed ledgers, but moreover helps to unify existing results.
Category / Keywords: cryptographic protocols / blockchain, distributed ledger, Corda, foundations, universal composability, ideal functionality, iUC Date: received 10 Feb 2021 Contact author: mike graf at sec uni-stuttgart de Available format(s): PDF | BibTeX Citation Version: 20210212:073420 (All versions of this report) Short URL: ia.cr/2021/145