Edge Computing Oriented Certificateless Sorting Ciphertext Retrieval Scheme

[Purposes] In order to ensure the privacy and retrievability of cloud data, ciphertext retrieval technology has emerged. However, cloud computing is no longer able to meet the current data processing requirements. To solve the problems of low efficiency and low security level in cloud computing ciphertext retrieval schemes, an efficient certificateless ciphertext retrieval scheme based on edge computing is proposed. [Methods] First, edge nodes were introduced to achieve ciphertext retrieval, for effectively sharing the computational cost of cloud computing while reducing the risk of leakage in data transmission paths. Second, by referencing the certificateless public key cryptosystem, the user’s public and private keys were generated and managed by themselves, which solved the problems of key escrow and certificate management in traditional schemes and improved the security of the system. Finally, by blocking the index and trapdoor to filter out keywords unrelated to the query, the secure KNN(k-nearest neighbor) algorithm was used to calculate document similarity, which improved retrieval efficiency and accuracy. At the same time, sorted ciphertext retrieval was achieved. [Results] The experimental results show that the proposed scheme is secure under known background threat models and has high efficiency.