Pattern-protecting Dynamic Searchable Symmetric Encryption Based on Differential privacy

Because it allows users to browse encrypted documents on an untrusted cloud server, searchable symmetric encryption has gotten a great deal of interest. However, based on the leakage of access and search patterns, the cloud server can infer users’ private data. Despite the fact that researchers have presented a number of strategies for protecting access or search patterns, all of them have a substantial computational and communication overhead. To that aim, this paper utilizes differential privacy technology to provide an efficient pattern-protecting dynamic searchable symmetric encryption scheme (DF-DSSE). Specifically, differential privacy’s false positives and false negatives are used to obfuscate the documents associated with each keyword, protecting access patterns. In particular, to reduce the computational and communication overhead associated by obfuscating query results, a tag symmetric encryption primitive is provided to encrypt indexes and query tokens. Furthermore, since the DF-DSSE scheme stores the token tags using the Bid Compress compression structure and accesses the documents corresponding to each keyword independently, an adversary cannot obtain the number of keywords or the frequency with which they are accessed, achieving the goal of protecting search patterns. In comparison to previous schemes, the DF-DSSE scheme enhances update and query efficiency and security, according to the security analysis and simulation experiment results.