A Lattice Homomorphic Proxy Re-encryption Method Against Strong Collusion Attacks

Abstract

The invention is a grid-based homomorphic proxy re-encryption method against strong collusion attack. The present invention relates to the technical field of information security. The present invention utilizes lattice-based trapdoor technology to generate re-encryption keys to resist strong collusion attacks, and then uses key exchange technology to construct re-encryption ciphertexts with homomorphic properties, thereby constructing a re-encryption key against Lattice homomorphic proxy re-encryption method for strong collusion attack, suitable for more complex cloud sharing environment. The present invention avoids that the traditional anti-proxy re-encryption method divides the ciphertext into two layers, one layer is the original ciphertext used to protect data, and the other layer is the re-encrypted ciphertext used for sharing, and the two layers are stored independently, requiring to interact. The proxy re-encryption method of the present invention only involves one layer of ciphertext, does not need to process the ciphertext in layers, and saves interaction overhead.

Description

technical field [0001] The invention relates to the technical field of information security, and relates to a grid-based homomorphic proxy re-encryption method against strong collusion attacks. Background technique [0002] Proxy Re-Encryption (PRE) is especially suitable for data cloud sharing. In a cloud sharing system, due to the limitation of terminal storage space, users will store data in the cloud. Once the data is out of the user's control, it will bring about data security issues, so users generally encrypt the data and store it in the cloud. When the data owner wants to share the data stored in the cloud with another user (data user), the data owner can use his private key and the data user's public key to generate a re-encryption key and send it to the cloud service business. The cloud service provider can use the re-encryption key to convert the ciphertext of the data owner into the re-encryption ciphertext of the data user. During this process, the cloud serv...

AI Technical Summary

Problems solved by technology

The re-encryption key constructed by the key exchange technology uses the data user's public key to encrypt the data owner's private key, so when the data user and the cloud service provider conspire, the data user can use their own private key to re-encrypt The key is decrypted to obtain the sum of the data user's private key and the decryption noise, which is an approximation of the private key, so it cannot resist strong collusion attacks

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