Lightshuffle: an Efficient and Secure Decentralized Coin Mixing Protocol

Coin mixing protocols are an effective privacypreserving mechanism that hides the correlation between the input and output addresses of transactions in blockchain systems by exchanging assets among multiple unrelated participants. CoinShuffle is one of the widely used decentralized coin mixing protocols. However, to prevent internal participants from leaking user privacy, CoinShuffle introduces a hierarchical encryptionbased information transmission protocol. Although this design enhances privacy, it also introduces inefficiency and certain security risks. To address these shortcomings, this paper proposes a more efficient and secure decentralized coin mixing protocol, LightShuffle, based on CoinShuffle. LightShuffle improves protocol efficiency by assigning the shuffling task to a subset of nodes, while also eliminating potential security risks by sorting the address list in lexicographical order. Security analysis and experimental results show that LightShuffle outperforms CoinShuffle in both security and efficiency.