Block chain-based proxy re-encryption method and system, and storage medium

Abstract

The invention discloses a block chain-based proxy re-encryption method and system, and a storage medium. The method comprises the following steps of respectively generating a public and private key pair of an authorizer and a public and private key pair of an authorized person, encrypting the data by using the public key of the authorizer, generating encrypted data and uploading the encrypted datato a cloud storage server, receiving an access request sent by the authorized person, the access request comprising a public key of the authorized person, and generating a re-encryption key by usingthe private key of the authorizer and the public key of the authorized person, sending the re-encryption key to an intelligent contract of a block chain, calling the intelligent contract to read the encrypted data from the cloud storage server, and re-encrypting the encrypted data by using the re-encryption key to generate re-encrypted data, and decrypting the re-encrypted data by using the private key of the authorized person. The agent can carry out distributed, transparent and verifiable agent re-encryption operation based on the block chain system.

Description

technical field [0001] The invention belongs to the technical field of applied cryptography, and more specifically relates to a blockchain-based proxy re-encryption method, system and storage medium. Background technique [0002] Proxy re-encryption technology belongs to cryptographic primitives, and is a key conversion protocol between ciphertexts. Generally speaking, in a proxy re-encryption system, the proxy (proxy) can convert the ciphertext originally encrypted to the delegator after obtaining the conversion key generated by the delegator (delegator) for the delegator (delegatee). For the authorized person's ciphertext, the authorized person only needs to use his own private key to decrypt the converted ciphertext. Proxy re-encryption can further ensure that although the proxy has the conversion key, the proxy still cannot obtain any information about the corresponding plaintext in the ciphertext. In reality, proxy re-encryption is widely used in many occasions, such ...

AI Technical Summary

Problems solved by technology

[0004] However, the problem with the traditional proxy re-encryption technology is that the behavior of the proxy is opaque

The current proxy re-encryption system usually requires an honest third-party agent, and has the characteristics of agent centralization, opacity, and non-public traceability. Therefore, in the case of malicious agents, there may be situations where the agent and the authorizer jointly deny the authorization fact. Happening

In addition, the public re-encryption key used in traditional proxy re-encryption technology may also bring security risks. For example, under certain algorithms, the re-encryption key and the authorized person's private key can be combined to derive the authorizer's private key.

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