Chainspace: A Sharded Smart Contracts Platform

TL;DR

Chainspace is a scalable, secure, and verifiable sharded smart contract platform that supports user-defined contracts and ensures integrity through Byzantine Fault Tolerance and auditing.

Contribution

It introduces a novel sharded architecture with a distributed commit protocol and auditing mechanisms for secure, scalable smart contract execution.

Findings

System demonstrates high scalability and performance.

Supports privacy-friendly smart contracts.

Ensures security and auditability even under Byzantine faults.

Abstract

Chainspace is a decentralized infrastructure, known as a distributed ledger, that supports user defined smart contracts and executes user-supplied transactions on their objects. The correct execution of smart contract transactions is verifiable by all. The system is scalable, by sharding state and the execution of transactions, and using S-BAC, a distributed commit protocol, to guarantee consistency. Chainspace is secure against subsets of nodes trying to compromise its integrity or availability properties through Byzantine Fault Tolerance (BFT), and extremely high-auditability, non-repudiation and `blockchain' techniques. Even when BFT fails, auditing mechanisms are in place to trace malicious participants. We present the design, rationale, and details of Chainspace; we argue through evaluating an implementation of the system about its scaling and other features; we illustrate a number of privacy-friendly smart contracts for smart metering, polling and banking and measure their performance.