Channelized coinShuffle++ : practical unlinkability in the ethereum blockchain

• Main Author: Xiong, Luoyuan
• Other Authors: Tay Wee Peng
• Format: Final Year Project
• Language: English
• Published: 2019
• Subjects: DRNTU::Engineering::Electrical and electronic engineering
• Online Access: http://hdl.handle.net/10356/77277
• Institution: Nanyang Technological University

Strong anonymity and transaction privacy for cryptocurrencies that build on top of a permissionless blockchain is a well-known hard problem. The duplication of ledger provides public verifiability while also give rise to deanonymization attacks and unlinkability violations, where users’ real world identities are linked to their pseudonymous blockchain accounts. Even though some recently proposed protocols that utilize Ring Signatures [1] or Zero Knowledge Proof [2] have effectively mitigated those attacks, the computational overhead and monetary cost that comes along with those fancy cryptographic primitives render them less usable, which arguably contribute to their poor adoption. In this work, we proposed a practical, peer-to-peer, coin mixing protocol in the Ethereum blockchain that significantly enhance transaction privacy and bring back the unlinkability property. The protocol is primarily inspired by CoinShuffle++ [3] and Generalized State Channel [4], and it enables secure, accountable and incentive-compatible shuffling while only requires very weak trust assumption, minimal cost and negligible delay. A complete system specification and theoretical evaluation will be provided while the actual experimental the result will appear in a future update once an end-to-end Proof of Concept is built.