YACL Talk | Feb 28, 11:00am | Ertem Nusret Tas, Stanford - Optimal Security in a Multi-chain World
Aviv Yaish
When: Friday (Feb 28), 11:00-noon
Where: AKW200, Arthur K. Watson Hall, 51 Prospect St, New Haven, CT 06511, US
Speaker: Ertem Nusret Tas (Stanford)
Title: Optimal Security in a Multi-chain World
Abstract: Following the invention of Bitcoin, there has been a proliferation of many permissionless blockchains. Each such chain provides a public ledger that can be written to and read from by anyone. In this multi-chain world, a natural question arises: what is the optimal security an existing blockchain, a consumer chain, can extract by only reading from and writing to ‘k’ other existing blockchains, so-called the provider chains? In this talk, we will answer this question in three ways: (1) We will first see a protocol, where an off-the-shelf PBFT-style proof-of-stake protocol (acting as a consumer chain) sends timestamps to Bitcoin (the provider chain) to reduce its stake withdrawal delay and to resolve issues such as non-slashable long-range safety attacks and low liveness resilience. (2) Applying the checkpointing method iteratively, we will then design a protocol called 'interchain timestamping', which enables a consumer chain to extract the maximum economic security from the provider chains, as quantified by the slashable safety resilience. (3) Finally, drawing an analogy with switching circuits, we will design two basic compositional operations between blockchains, serial and triangular compositions, and use these operations as building blocks to construct general overlay blockchains that read from and write to a given set of blockchains. This talk is based on the following papers: 1. Bitcoin-Enhanced Proof-of-Stake Security: Possibilities and Impossibilities (IEEE S&P 2023), 2. Interchain Timestamping for Mesh Security (ACM CCS 2023), 3. A Circuit Approach to Constructing Blockchains on Blockchains (AFT 2024).
Bio: Ertem Nusret Tas is a PhD student in Electrical Engineering at Stanford University, working with Prof. David Tse on the analysis of blockchains. He completed both his BS and MEng degrees at the Electrical Engineering and Computer Science department at MIT. His current research focuses on blockchains, consensus protocols and cryptography. He has previously completed summer internships at a16z Crypto Research, BabylonChain, Celestia and Apple. He received a distinguished paper award at ACM CCS 2024, and his papers on blockchains, consensus protocols and cryptography have appeared in top venues such as ACM CCS, IEEE S&P, Financial Cryptography (FC) and Advances in Financial Technologies (AFT).
Livestream: https://yale.zoom.us/j/97267066793?pwd=FTPufHHfOVSRMAUnuB3y0GqyloM2mA.1 (Password: 699387, Telephone: 203-432-9666 or 646 568 7788)
More: For additional details about the talk and our seminar, see our website: https://yacl.cs.yale.edu