Ekiden: A Platform for Confidentiality-Preserving, Trustworthy, and Performant Smart Contract Execution

TL;DR

Ekiden is a blockchain system that combines Trusted Execution Environments with a novel architecture to significantly improve confidentiality, scalability, and performance of smart contract execution, addressing key limitations of existing blockchain platforms.

Contribution

The paper introduces Ekiden, a new hybrid system that separates consensus from execution, enabling efficient confidential smart contracts with high scalability and performance, and systematically analyzes TEE-blockchain security pitfalls.

Findings

Achieves 600x throughput increase over Ethereum

Reduces latency by 400x and cost by 1000x

Identifies security challenges in hybrid TEE-blockchain systems

Abstract

Smart contracts are applications that execute on blockchains. Today they manage billions of dollars in value and motivate visionary plans for pervasive blockchain deployment. While smart contracts inherit the availability and other security assurances of blockchains, however, they are impeded by blockchains' lack of confidentiality and poor performance. We present Ekiden, a system that addresses these critical gaps by combining blockchains with Trusted Execution Environments (TEEs). Ekiden leverages a novel architecture that separates consensus from execution, enabling efficient TEE-backed confidentiality-preserving smart-contracts and high scalability. Our prototype (with Tendermint as the consensus layer) achieves example performance of 600x more throughput and 400x less latency at 1000x less cost than the Ethereum mainnet. Another contribution of this paper is that we systematically identify and treat the pitfalls arising from harmonizing TEEs and blockchains. Treated separately, both TEEs and blockchains provide powerful guarantees, but hybridized, though, they engender new attacks. For example, in naive designs, privacy in TEE-backed contracts can be jeopardized by forgery of blocks, a seemingly unrelated attack vector. We believe the insights learned from Ekiden will prove to be of broad importance in hybridized TEE-blockchain systems.