Teechan: Payment Channels Using Trusted Execution Environments

TL;DR

Teechan introduces a secure, high-performance off-chain payment channel framework leveraging trusted execution environments, achieving significantly higher throughput and lower latency on Bitcoin without protocol modifications.

Contribution

It presents Teechan, a novel payment channel system using trusted execution environments that enhances scalability and security without requiring changes to the Bitcoin protocol.

Findings

Achieves 2,480 transactions per second on a single channel

Enables full-duplex payments with minimal blockchain transactions

Requires only one message per payment in either direction

Abstract

Blockchain protocols are inherently limited in transaction throughput and latency. Recent efforts to address performance and scale blockchains have focused on off-chain payment channels. While such channels can achieve low latency and high throughput, deploying them securely on top of the Bitcoin blockchain has been difficult, partly because building a secure implementation requires changes to the underlying protocol and the ecosystem. We present Teechan, a full-duplex payment channel framework that exploits trusted execution environments. Teechan can be deployed securely on the existing Bitcoin blockchain without having to modify the protocol. It: (i) achieves a higher transaction throughput and lower transaction latency than prior solutions; (ii) enables unlimited full-duplex payments as long as the balance does not exceed the channel's credit; (iii) requires only a single message to be sent per payment in any direction; and (iv) places at most two transactions on the blockchain under any execution scenario. We have built and deployed the Teechan framework using Intel SGX on the Bitcoin network. Our experiments show that, not counting network latencies, Teechan can achieve 2,480 transactions per second on a single channel, with sub-millisecond latencies.