EE Seminar: Teechain: Scalable Blockchain Payments using Trusted Environments
(The talk will be given in English)
Speaker: Dr. Ittay Eyal
Faculty of Electrical Engineering, Technion
Monday, June 11th, 2018
15:00 - 16:00
Room 011, Kitot Bldg., Faculty of Engineering
Teechain: Scalable Blockchain Payments using Trusted Environments
Abstract
Blockchain protocols such as Bitcoin and Ethereum exchange payments in a secure and decentralized manner, but their performance is limited due to their need to achieve consensus across a network. Cryptographic payment channels have been proposed as a second tier on top of the blockchain, allowing efficient direct payments between parties. Existing payment channel protocols, however, have two limitations: (i) Their security relies on synchronous access to the underlying blockchain, which an attacker may prevent; and (ii)~they suffer from long channel establishment times when placing collateral deposits on the blockchain. We describe Teechain, a payment network that supports secure and scalable payments for blockchain-based cryptocurrencies using hardware trusted execution. Teechain creates chains of payment channels using multiple entangled trusted execution environments~(TEEs). Teechain is the first payment network that assumes asynchronous blockchain access and does not require bounded write-access to the blockchain. It also permits payment channels to be established near instantly by dynamically assigning deposits: deposits are not tied to a specific channel but can be moved between channels. To overcome TEE crash failures, Teechain uses a novel replication protocol between TEEs that may be of independent interest. We experimentally evaluate our Teechain implementation and show that it achieves orders of magnitude improvement in performance compared to existing solutions; with replicated Teechain nodes in a trans-atlantic deployment, we measure a throughput of between 33,000--135,000 transactions per second with 0.3 second latency, in comparison to the current state of the art which achieves 1,000 transactions per second. Moreover, Teechain payment channels place 25%--83% less transactions and data on the blockchain than existing payment solutions.
