A Ring Signature With Aggregation for Ensuring Privacy in Blockchain Transactions

Ring signatures are a crucial cryptographic tool underpinning blockchains and blockchain-based systems, and there are ongoing efforts to design different ring signatures to provide varying properties in a range of applications (e.g., batch verification of numerous ring signatures). In this article, we propose an efficient aggregate ring signature (ARS) scheme for anonymous transaction verification in blockchain. First, a comprehensive definition and the formal security model of our proposed ARS scheme are given, where the true identity of the signer will be protected against both the verifier and other signers contributing to the signature. Furthermore, we present a concrete ARS scheme that can aggregate multiple signatures produced by different signers of the same ring, by exploiting the compressed $\Sigma $ -protocol. There are no interactions required among signers and only one single round between each signer and the aggregator. Building on the proposed ARS scheme, we present a confidential transaction (CT) protocol called ARSCT. The latter allows multiple transactions to be aggregated into one transaction. Finally, the formal security proof demonstrates our proposed ARS scheme achieves both anonymity and unforgeability, where signers’ anonymity is protected against both the verifier and the aggregator. Performance evaluations show that in simultaneous multiple signers situation, our scheme outperforms other mainstream ring signature schemes in verification efficiency.