A Study On SGX-based Traceable Anonymous Scheme For Permissioned Blockchain

The popularity of digital currencies such as Bitcoin has made people aware of the enormous potential of its core technology-blockchain.A blockchain is a decentral-ized system in which the information disclosed is publicly verifiable and can not be tampered.As the blockchain get more and more attention,privacy-related issues have become more serious.The transparency of the blockchain provides,on the one hand,the ability to publicly verify the information it records,but on the other hand the risk of leakage of the user's private information.In order to protect the user privacy in the blockchain,many solutions including zero-knowledge proof,mixcoin and other technologies have been proposed.How-ever,the scenarios targeted by these solutions are some completely“decentralized"permissionless blockchains like Bitcoin.For permissioned blockchains in which that generally have audit requirements,existing solutions cannot provide safe and reliable traceability.To satisfy audit requirements in the permissioned blockchains,this paper proposes a traceable anonymous scheme based on Intel SGX.In our solution,user does not need to rely on the trusted third party.User can independently extract the anonymous ac-count with original account.The auditor can decrypt anonymous account and locate the corresponding original account.The solution in our paper guarantees the unforge-ability of the user's identity and allows anyone to verify the integrity of the process of extracting an anonymous account.At the same time,considering that the account in the current permissioned blockchains is generally based on the certificate signature mode,key management is not efficient.In our paper,based on the former scheme,detailed key management methods are pro-posed,which provide solutions for hierarchical authorization and access control sce-narios.The main consideration of the former scenario is that there is a hierarchical system among multiple accounts,and the anonymous account derivative of the lower-level users depends on the management authorization of the superior user.The latter mainly considers that a single account corresponds to a group with many different roles,and a single account extracts different levels keys so that with different keys,each role in the group has different rights.We experiment all schemes and test the performance of the SGX.In addition,we compare and analyze the performance of the schemes in different scenarios.