ZkChain: A privacy‐preserving model based on zk‐SNARKs and hash chain for efficient transfer of assets

Abstract

AbstractAs a distributed public ledger technology in a peer‐to‐peer network, blockchain has been widely used in a variety of Internet interaction systems in recent years, such as market supervision, property rights protection, and digital identity. However, in blockchain environment, all historical transaction data are open and transparent, and adversaries may illegally access private transaction data, which makes privacy attacks a core issue that hinders the popularization and application of blockchain. Different privacy‐preserving technologies such as zerocoin and zerocash have been proposed. However, the large amount of proofs and the slow verification speed hinder the effective application of zero‐knowledge proofs (ZKPs) in blockchain. This article proposes a privacy‐preserving model based on zk‐SNARKs and hash chain for efficient transfer of assets, called zkChain. Different from traditional privacy‐preserving schemes, this scheme constructs a smaller proof based on hash chain, and the verification speed of the proof is faster. This scheme constructs ZKP based on the one‐way hash function and zk‐SNARKs. The proof is publicly recorded in the ledger after being verified by miners, and users use the proof to send privacy‐preserving transactions. In the above process, the zkChain scheme can achieve effective privacy protection of account balance and account address. We evaluated the computational and storage costs of the zkChain scheme based on libsnark, and establish a test network to evaluate the processing performance of the zkChain scheme.