Research On Blockchain-Based Data Protection Technology

With the increasing development of Internet technology,the scale of data sharing continues to expand,and data privacy protection has become a research hotspot in the field of information security.Meanwhile,the increasing number of shared participants has also brought new challenges to the privacy protection for multi-party data.At present,Most systems currently adopt centralized data management mechanisms,but centralization restricts autonomy,reliability and flexibility of data.and how to ensure the confidentiality of data and data storage have also a core issue.As the rapid development of electronic cryptocurrencies,such as Bitcoin,blockchain has become a topic with widespread concern.Blockchain is a technology for building distributed databases that has the characteristics of decentralization.Data added on the blockchain is collectively maintained by system participants and permanently recorded with data that cannot be modified.Therefore,the stability and reliability of the data on the blockchain is extremely high.Based on this,this thesis mainly finishes the following two tasks:(1)A blockchain-based data protection and payment privacy scheme is proposed,which realizes the scalable storage and privacy protection of data on the blockchain,and solves the problem that a large amount of data cannot be stored in the blockchain.We utilize blockchain technology to prevent shared data from being tampered with,and adopt NTRU cryptosystem to implement the confidentiality of shared data.We prove the scheme not merely meet basic security features such as confidentiality and authentication,but also resists quantum attacks through privacy analysis.Experimental results verify the comparable computational cost in the key generation,encryption and decryption phase of the scheme,which also has good scalability and is suitable for data sharing in multi-party environment.(2)A blockchain-based data sharing scheme is proposed,Which utilizes proxy re-encryption and efficient sign-cryption data access control technology.The proxy re-encryption keeps the cloud server being unable to obtain any plaintext information from stored data,and the information can only be accessed by the authorized user.Blockchain technology gives rises to public known of access behavior to all users on the chain,therefore reducing the probability of illegal access to information.The data in ourscheme not only has the confidentiality,integrity,unforgeablity,but also has the ciphertext certification.In the random prediction model,we prove that the proposed scheme is indistinguishable from adaptive selective ciphertext attack under the decision bilinear Diffie-Hellman problem,and satisfies strong unforgeablity in adaptive selection message attack under the computation Diffie-Hellman problem.Finally,the scheme is implemented by PBC library,which proves that the scheme has obvious advantages in communication cost and computation cost.