关键词: 区块链, 可信网络, 多重认证, 无证书公钥密码体制, 标识密码

Abstract:

In order to solve the problem that the traceability and privacy protection of the existing blockchain systems are difficult to balance， a supervisable blockchain anonymous transaction system model was designed. Firstly， the advantages of Identity-Based Cryptograph （IBC） and Certificateless Public Key Cryptography （CL-PKC） were combined to remove the hidden dangers caused by the single IBC key escrow， and the user transaction identification was associated with the user identity under safe conditions， thereby ensuring the supervisability of the model. Then， privacy security was achieved through double-layer signature authentication from the network layer and the application layer， which not only guaranteed the security of users’ transaction content and identity privacy， but also ensured that the authority was able to trace back based on abnormal transactions， providing a new idea for the compatibility between the current blockchain anonymity and supervisability. Finally， the proposed model was compared with the self-certified signature model， the multi-center SM9 model and the traceable Monero model， and the transmission time consumptions of this model and the mainstream blockchain systems were compared by computer simulation. Experimental results show that the proposed model has greater advantages in security and traceability； under the same hardware and software environment， the proposed model consumes 168% more time than the Ethereum model when transmitting the same size information for several times， and the difference in efficiency is not significant in the case of long-time transmission； the proposed model consumes 38% more time than the Ethereum model on average when transmitting information of different lengths.

Key words: blockchain, trusted network, multiple authentication, Certificateless Public Key Cryptography (CL-PKC), Identity-Based Cryptography (IBC)