LazyLedger: A Distributed Data Availability Ledger With Client-Side\n Smart Contracts

Abstract

We propose LazyLedger, a design for distributed ledgers where the blockchain\nis optimised for solely ordering and guaranteeing the availability of\ntransaction data. Responsibility for executing and validating transactions is\nshifted to only the clients that have an interest in specific transactions\nrelating to blockchain applications that they use. As the core function of the\nconsensus system of a distributed ledger is to order transactions and ensure\ntheir availability, consensus participants do not necessarily need to be\nconcerned with the contents of those transactions. This reduces the problem of\nblock verification to data availability verification, which can be achieved\nprobabilistically with sub-linear complexity, without downloading the whole\nblock. The amount of resources required to reach consensus can thus be\nminimised, as transaction validity rules can be decoupled from consensus rules.\nWe also implement and evaluate several example LazyLedger applications, and\nvalidate that the workload of clients of specific applications does not\nsignificantly increase when the workload of other applications that use the\nsame chain increase.\n