A Pairing-free Dynamic Multi-receiver Certificateless Authenticated Searchable Encryption for cloud storage

In the current age of constrained local storage capacity, ensuring the security and privacy of user data against unauthorized third-party access has grown significantly more vital. Searchable Encryption (SE) has arisen as a promising method for preserving the confidentiality of user data while also enabling efficient search capabilities. Certificateless Searchable Encryption (CLSE) stands out among a range of SE cryptosystems by effectively addressing issues related to certification management and key escrow. Nevertheless, the majority of current CLSE approaches heavily depend on computationally intensive bilinear pairings and do not offer robust support for conjunctive keyword searches in multi-receiver scenarios. To address these limitations, we propose a Pairing-free Dynamic Multi-receiver Certificateless Authenticated Searchable Encryption (PDMCLASE) scheme. PDMCLASE focuses on three essential features: (1) Dynamic multi-receiver functionality, enabling new data receivers to access documents while revoking access for existing receivers; (2) Conjunctive subset keyword search, empowering data receivers to perform efficient conjunctive searches on subsets of keywords; and (3) Data sender authentication, ensuring the authenticity of keyword encryption by the data sender. Furthermore, PDMCLASE attains keyword privacy by leveraging elliptic curve hardness problems within the standard model. Through our performance analysis, we establish that PDMCLASE not only delivers improved functionality but also demonstrates reduced computational overhead when compared to alternative schemes.