Block chain data sharing method and device based on LWE-CPABE and storage medium

Abstract

The invention discloses a block chain data sharing method and device based on LWE-CPABE and a storage medium, and the method comprises the following steps: a data visitor sets an access control strategy, generates a master key and a public key based on the access control strategy, sends the public key to a block chain for storage, the master key entrusts a key center for storage, and the public key entrusts the key center for storage. Data to be published are encrypted into a ciphertext, the ciphertext is uploaded to the third-party storage, and the third-party storage sends a ciphertext storage address to the block chain; the data user obtains the master key from the key center, then synthesizes the master key into a user attribute key, and decrypts the obtained ciphertext by using the user attribute key to complete data sharing; according to the method, the security and the efficiency of data sharing are relatively high, the access control strategy can be conveniently updated, the calculation amount in the updating process is small, and more key space cost and encryption time cost are saved.

Description

technical field [0001] The invention belongs to the technical field of block chain, in particular to a block chain data sharing method, equipment and storage medium based on LWE-CPABE. Background technique [0002] With the continuous popularization of blockchain technology, it has become very popular to use blockchain for data sharing in weak or trustless networks. The privacy data protection on the chain has become a new challenge; in recent years, many scholars have proposed new solutions for privacy protection and data sharing on the blockchain, among which, the attribute-based encryption algorithm is due to its one-to-many encryption and can The advantages of realizing fine-grained access control are widely used in various blockchain solutions, such as data traceability, cloud storage, medical data sharing, and the Internet of Things. [0003] Attribute-based encryption (ABE) originated from the fuzzy identity-based encryption proposed by Sahai and Waters in 2005, and ...

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Problems solved by technology

[0005] However, with the continuous development of quantum computing, the difficulty of problems based on number theory will be greatly reduced, and the traditional public key cryptosystem based on number theory is facing the risk of being cracked. Security foundation, with the security that cannot be solved under the assumption of the most difficult situation, it can well resist quantum attacks; at present, the lattice difficulty problems that are proved to be safe mainly include small integer solution problem (Small integer Solution Problem, referred to as SIS) and fault tolerance Learning with errors Problem (LWE for short), two difficult problems are reduced from the worst-case ideal lattice problem to the general variant problem, and have high computational efficiency and easy storage. At present, lattice-based encryption schemes have been proposed one after another. However, it mainly focuses on identity-based encryption, digital signatures, and zero-knowledge proofs. In May 2021, Datta et al. constructed an attribute-based encryption algorithm based on a ciphertext strategy based on the LWE difficulty problem, and realized quantum-resistant attacks. CPABE scheme, but this scheme only supports directional encryption and decryption. When the data user group changes, the policy cannot be updated.

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