基于双层协同的联盟区块链隐私数据保护方法

为了解决联盟区块链平台中的隐私保护问题，提出了一种基于双层协同的隐私数据保护方法，包括：（1）链间隐私保护：通过将不同业务的数据进行分流处理、分区存储，实现了不同业务之间的隐私机密性保护；（2）链内隐私保护：通过在交易体中嵌入字段来指定链内隐私数据的参与方，并由接收交易的区块链节点作为中转节点进行链内隐私数据的同步，中转节点同时负责将隐私数据替换成其哈希值后，构造公开交易进行正常公开交易的上链，待公开交易上链成功后，由隐私参与方节点各自进行隐私账本的更新.为了验证该方法的有效性，分别对链间隐私方法吞吐量以及链内隐私保护方法的延迟性进行了测试与对比，结果表明，通过结合粗粒度的链间隐私保护与细粒度的链内隐私保护，在满足了隐私需求的同时，也保证了可观的性能，为区块链平台的隐私性与安全性做出了贡献.

Private Data Protection Scheme for Consortium Blockchain Based on Two-layer Cooperation

This study proposes a two-layer collaborative approach for privacy protection in consortium blockchain. The proposed approach consists of two layers. 1. Inter-chain privacy protection: such protection approach aims to protect the privacy between different businesses. This approach is realized by separating and storing the data of different businesses. 2. Intra-chain privacy protection: such protection approach is realized by embedding collection field into transaction body to specify the participants of privacy protection. Then, this approach regards the receiving blockchain node as a relay node to synchronize private data. At the same time, the relay node is also responsible to construct a public transaction by replacing the private payload with its hash after which the public transaction will be synchronized to all participants through consensus. Finally, private participant nodes update their private ledgers to achieve intra-chain privacy. To verify the validity of the proposed approach, some experiments are designed to measure the throughput of inter-chain privacy protection and the delay of intra-chain privacy protection. The experimental results show that the privacy protection approach which is combined with coarse-grained inter-chain protection and fine-grained intra-chain protection ensures the considerable performance and satisfies the privacy requirements at the same time. Thus, the proposed approach has made a potential contribution to the privacy and security of blockchain platform.