Cross-chain interaction of consortium blockchain not only enhances the function of the application of consortium blockchain， but also expands the scope of usage of the application， so that it is of great significance to the application promotion and industrial development of consortium blockchain. However， the cross-chain interaction of consortium blockchain still has the privacy disclosure problems of user identity and asset transaction information at present， which has become a major factor hindering the wide application of the cross-chain interaction technology of consortium blockchain. In view of the above problems， a cross-chain privacy protection scheme for consortium blockchain assets based on improved notary mechanism was proposed. In the scheme， a hash locking mechanism was introduced at the contract layer to improve the traditional single-signature notary cross-chain method at first， so as to reduce the risk of the traditional notary mechanism centralizing and doing evil. Then， the characteristics of homomorphic encryption were used to realize the usability and invisibility of transaction assets under the premise of ensuring the legitimacy of transactions. At the same time， the identity-based cryptographic algorithm of multi-Key Generation Center （KGC） mode was used to protect the user identity privacy at the network layer. The theoretical analysis and experimental results show that the proposed scheme has a good privacy protection effect on the user identity information and asset information in the cross-chain interaction of consortium blockchain， and this scheme has lower overhead in signature and verification than other similar schemes.
