An Efficient Linkable Group Signature for Payer Tracing in Anonymous Cryptocurrencies

TL;DR

This paper introduces an efficient linkable group signature scheme that enhances privacy and accountability in anonymous cryptocurrencies, enabling payer tracing while maintaining user anonymity during honest transactions.

Contribution

It proposes a novel linkable group signature scheme tailored for blockchain-based cryptocurrencies, balancing anonymity with the ability to trace malicious actors.

Findings

Scheme achieves full-anonymity and full-traceability

Demonstrates high efficiency suitable for real-world deployment

Ensures linkability to identify repeat offenders

Abstract

Cryptocurrencies, led by bitcoin launched in 2009, have obtained wide attention due to the emerging Blockchain in recent years. Anonymous cryptocurrencies are highly essential since users want to preserve their privacy when conducting transactions. However, some users might misbehave with the cover of anonymity such as rampant trafficking and extortion. Thus, it is important to balance anonymity and accountability of anonymous cryptocurrencies. In this paper, we solve this issue by proposing a linkable group signature (LGS) for signing cryptocurrency transactions, which can be used to trace a payer's identity in consortium blockchain based anonymous cryptocurrencies, in case the payer tries illegal activities. A payer keeps anonymous if he/she behaves honestly. We prove that the proposed scheme achieves full-anonymity, full-traceability and linkability in the random oracle. Implementation of the proposed LGS scheme demonstrates its high efficiency thus, can be adopted in anonymous cryptocurrencies in reality.