A Privacy Preserving Public-Key Searchable Encryption Scheme with Fast Keyword Search

Searchable encryption has emerged in order to maintain the balance between data privacy and convenience of keyword search. In 2017, Huang et al. introduced the notion of inside keyword guessing attack (IKGA), which means the inside adversary could try out the keyword specified by a given trapdoor by guessing offline and proposed a scheme called Public-key Authenticated Encryption with Keyword Search (HQ-PAEKS) to solve this problem. However, the search complexity of HQ-PAEKS is linear to the total number of the encrypted indexes and may be not in a position to meet the demand of practical application. This paper combines the idea of Public-key Authenticated Encryption with hidden structure and proposes a practical scheme called Public-key Authenticated Encryption with Fast Keyword Search (PAEFKS), in which the search complexity for the cloud server presents linear relation with the number of the encrypted indexes matching the trapdoor sent from the data user. In addition, it gives security analysis to show that the scheme could protect index and keyword privacy well and experiments on real-world data sets show that the scheme indeed reduces the overhead on keyword search computation in the cloud.