| The advent of the Internet era has pushed the education industry towards digital transformation,and with the rapid development of technologies such as networks,storage and computing,there are various ways to obtain data,and phenomena such as theft of resource data and falsification of evaluation information are emerging,so how to verify data trustworthiness has become a focal issue in the development of digital education nowadays.Therefore,relevant research has introduced blockchain as a technical support,which is mainly divided into four types of demand scenarios: education resource authentication,education process data recording,education evaluation and education assessment,and data deposition is the premise and foundation of all demand scenarios.Therefore,this paper mainly focuses on the research of education data storage.The education data depository is divided into two steps: data up-chain and trusted query.When data is up-chain,due to the open and transparent nature of blockchain,all users can directly query the original data and there is a direct risk of data privacy leakage.Many cryptography-based solutions have been proposed to address this problem,but they all suffer from low ease of use or high computational overhead,and cannot be applied to educational application scenarios with many data types and complex query logic.This paper therefore proposes a smart contract-based permission management solution that balances computational overhead and ease of use while protecting data privacy.However,aggregated queries often expose the statistical results,posing the risk of differential privacy disclosure,and the problem cannot be avoided through permission management.To address this problem,work has typically taken the approach of adding noise to statistics to protect user privacy,but under the assumption that nodes in a blockchain are not trusted by each other,a direct combination of this approach cannot guarantee that queries are trusted,so this paper designs a corresponding verification structure to support differentially secure verifiable queries on the chain.To summarise the main work of this paper,the following are presented:(1)A smart contract-based permission management solution is proposed for the education deposition scenario.A fully decoupled smart contract architecture is designed to separate logic from data to improve contract update performance,combined with off-chain storage and version checking mechanisms to optimise contract invocation overhead.(2)A differentially secure verifiable statistical query is designed for educational deposition scenarios.The LDP approach is combined into the blockchain and the statistics are modelled to optimise the efficiency of data upload and lookup; a verifiable structure based on prefix signature chains and interval counting mechanisms is designed to support single-attribute and multi-attribute range statistical query verifiability; and finally experiments are conducted to verify the performance of the scheme.(3)A blockchain education depository system is designed and implemented.The system integrates the above privacy protection scheme and provides a trusted certificate deposit,query and data statistics service for educational evaluation,and finally demonstrates the system functionality and conducts experiments to verify the practicality of the system.In summary,this paper investigates the blockchain privacy issue in the education depository scenario from two directions: direct data privacy and differential data privacy on the blockchain,and designs and implements an efficient,flexible and scalable permission access contract scheme and a differentially secure and verifiable statistical query scheme respectively. |
