Research On Searchable Encryption For Privacy Preserving Of Blockchain Data

Blockchain has the unique advantages of de-trust,weak centralization,data traceability and tamper resistance,and is gradually becoming a popular platform for data storage sharing.Reasonable data organization management and perfect data privacy protection mechanism are the key factors for the data platform to be recognized.However,because the blockchain is designed to decentralize digital currency,its data organization form is solidified,resulting in a single retrieval method and Lack of related efficient data privacy preserving scheme,which hinders the blockchain's strong data security requirements.And related areas of data query needs,such as smart healthcare,financial technology and e-government.The searchable encryption technology may enable the blockchain data to meet the secure storage requirements while supporting efficient retrieval.However,at present,it is mostly for the searchable encryption research in the cloud environment,and lacks the searchable encryption research for the blockchain data platform.In this thesis,the related research on the safe storage and safe and efficient retrieval of sensitive data on the blockchain is carried out.The main work is as follows:1.Research on searchable optimization methods in blockchain data in plain text,enriching its search methods.Facing the problem of blockchain data organization form solidification,single query mode,unable to meet security requirements and data analysis requirements,through research and analysis of the current mainstream blockchain platform data organization storage,from the perspective of data storage structure,query mode,etc.Analyzed and summarized three optimization methods: external database query middleware method,built-in index optimization method,internal database replacement method,and compared their advantages and disadvantages from multiple angles,providing clear information on blockchain data organization difficulties the solution route.2.Blockchain data can be searched for encryption technology research,designed to support encrypted data search schemes and corresponding system architecture.Aiming at the security retrieval requirements of blockchain data,a searchable encryption scheme that supports forward privacy and resists data leakage is introduced.This scheme achieves double security and improves query efficiency.Compared with the algorithm experiments of two classic papers,the scheme introduced in this thesis reduces the time consumption of security index construction by nearly 50%,and the proportion of ciphertext index space increases linearly.On the data set with the keyword size of 107,the index size maintained within 1G.The gap with the comparison program is not large,which is in a reasonable range.3.According to the second point of the searchable encryption scheme design,for the medical data scenario,detailed requirements analysis and functional design are implemented,and a file sharing system based on the fabric platform to support data searchable encryption is designed and implemented.By simulating multi-node functional testing,it is verified that the system satisfies the searchable encryption requirements for blockchain data proposed in this thesis,and fills in the blank of the data searchable encryption scheme of the blockchain as a data sharing platform,which provides for subsequent related research.A certain reference meaning.At present,there is no research on the combination of searchable encryption schemes for blockchain data.This thesis derives the search optimization for blockchain plaintext data from the key research and development projects in the laboratory-blockchain data storage and transmission.Aiming at the search implementation of ciphertext data,a searchable encryption scheme for blockchain data satisfying double security is realized,which has certain practical value and also provides a new direction for the related theoretical research of blockchain data sharing.