Cryptology ePrint Archive: Report 2017/684

Z-Channel: Scalable and Efficient Scheme in Zerocash

Yuncong Zhang and Yu Long and Zhen Liu and Zhiqiang Liu and Dawu Gu

Abstract: Decentralized ledger-based cryptocurrencies like Bitcoin present a way to construct payment systems without trusted banks. However, the anonymity of Bitcoin is fragile. Many altcoins and protocols are designed to improve Bitcoin on this issue, among which Zerocash is the first full-fledged anonymous ledger-based currency, using zero-knowledge proof, specifically zk-SNARK, to protect privacy. However, Zerocash suffers two problems: poor scalability and low efficiency. In this paper, we address the above issues by constructing a micropayment system in Zerocash called Z-Channel. First, we improve Zerocash to support multisignature and time lock functionalities, and prove that the reconstructed scheme is secure. Then we construct Z-Channel based on the improved Zerocash scheme. Our experiments demonstrate that Z-Channel significantly improves the scalability and reduces the confirmation time for Zerocash payments.

Category / Keywords: Cryptocurrency, Blockchain, Zerocash, Privacy, Instant payment

Original Publication (with major differences): Australasian Conference on Information Security and Privacy 2018

Date: received 9 Jul 2017, last revised 15 Apr 2018

Contact author: shjdzhangyuncong at sjtu edu cn

Available format(s): PDF | BibTeX Citation

Version: 20180416:012834 (All versions of this report)

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