Research On Ciphertext Data Retrieval Scheme Based On Cloud-edge Collaboration

The Internet of Things technology enables real-time control and scientific management of the physical world,but leakage,misuse and tampering of Internet of Things data can constrain the development of Internet of Things technology.To prevent privacy leaks,Internet of Things data is usually transmitted in the form of ciphertext over open channels,but ciphertext data makes retrieval operations more difficult.Ciphertext retrieval technology supports efficient search of ciphertext data and can significantly improve the flexibility of data sharing.In a data-intensive Io T environment,Io T devices need to take advantage of both the powerful storage and computation capabilities of cloud servers and the short-time computation and transmission characteristics of edge servers to respond to users’ retrieval needs.To realize secure and efficient retrieval of Io T data in the cloud-edge collaboration scenario,this paper proposed the following three ciphertext data retrieval schemes based on cloud-edge collaboration to address the problems of single-user retrieval,unsupported search result verification and fine-grained access control.To solve the problem that ciphertext data retrieval schemes cannot support multiuser search and inaccurate retrieval,a multi-user certificateless ciphertext retrieval scheme based on cloud-side collaboration was proposed.The proposed scheme set a user access permissions table and generated keyword ciphertext containing multiple user identity information to realize multi-user search and update users’ access permissions.A cloud-edge collaboration keywords matching calculation mode was introduced,and the scheme can return the ciphertext file containing the most search keywords when the keyword indexes do not entirely contain the search keywords.Key escrow and certificate management issues were solved based on the certificateless cryptosystem.The unforgeability of keyword ciphertext and search trapdoors were ensured by using digital signature technology.Security and performance analysis results show that the scheme can resist the chosen keyword attack and has good computational performance.To solve the problem of ciphertext data retrieval schemes having low-security levels and do not support the verification of search results,a verifiable ciphertext data retrieval scheme based on cloud-side collaboration was proposed.The scheme verified the authenticity and integrity of search results by using Merkle hash trees and the blockchain.A search reward and punishment mechanism was proposed based on smart contracts to encourage search entities honestly perform ciphertext retrieval tasks.The cloud-side collaborative computing architecture was used for keyword matching calculation and search result verification to reduce the computing pressure of the cloud server.The security analysis and simulation results show that the scheme can resist internal keyword guessing attacks and has good computational efficiency.To solve the problem of the ciphertext data retrieval schemes do not support finegrained access control and do not satisfy forward security,a multi-authority attributebased ciphertext retrieval scheme based on cloud-side collaboration was proposed.This scheme implemented fine-grained access control of ciphertext data and realized user attribute revocation using attribute-based encryption and subset cover trees.Multiple authorities generated user attribute keys jointly to solve the computing bottleneck problem of single attribute authority.Forward security of the scheme was ensured based on the one-way nature of the hash function in the hash chain.The cloud-edge collaboration computing technology was introduced for offline encryption,keyword matching computing and outsourcing decryption,which effectively reduces the computing overheads of users and the cloud server.The security analysis results show that the scheme is selectively indistinguishable under the chosen keyword attacks.