Cryptology ePrint Archive: Report 2019/925

Fully regulatable privacy-preserving blockchains against malicious regulators

Wulu Li and Lei Chen and Xin Lai and Xiao Zhang and Jiajun Xin

Abstract: Privacy protection has been extensively studied in the current blockchain research field. As representations, Monero and Zerocash have realized fully anonymous and amount-hiding transactions. However, nonregulation can lead to abuse of privacy, which brings about serious risks of breaking laws and committing crimes. Therefore, it is crucial to study the privacy-preserving blockchain systems with regulatory functions. In this paper, we discuss the regulatory model (regulator behavior, user behavior) on the privacy-preserving blockchains from application scenarios and finally select unconditional regulation, static regulation, and self-participation of users as the core principles, which is currently the closest approach to "decentralization" in regulatable privacy-preserving blockchains. On the basis of the established regulatory model, we propose a traceable and linkable ring signature scheme (TLRS) by usage of classic ring signatures, one-time signatures and zero-knowledge proofs. TLRS achieves unforgeability, anonymity, linkability, nonslanderability and traceability against malicious regulators under standard assumptions. Moreover, we give the first construction of traceable range proofs, including traceable Borromean range proof (TBoRP) and traceable Bulletproofs range proof (TBuRP) by usage of zero-knowledge proofs and DH assumptions, with completeness, soundness, zero-knowledge and traceability of the transaction amounts. We modify the TBoRP to achieve security against malicious regulators by adding the mirror commitments. In addition, we discuss the traceability for long-term addresses, which finishes the first construction of the fully regulatable privacy-preserving blockchains against malicious regulators.

Category / Keywords: public-key cryptography / Regulatable blockchains, Privacy preserving, Decentralization, Traceable and linkable ring signatures, Traceable range proofs, Malicious regulators

Date: received 14 Aug 2019, last revised 26 Sep 2019

Contact author: liwulu at onething net

Available format(s): PDF | BibTeX Citation

Note: We give the first construction of the fully regulatable privacy-preserving blockchains against malicious regulators by usage of traceable and linkable ring signatures (TLRS), traceable Borromean range proof (TBoRP) and traceable Bulletproofs range proof (TBuRP). If you have comments or suggestions, please contact us by e-Mail.

Version: 20190926:155403 (All versions of this report)

Short URL: ia.cr/2019/925


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