A pairing-free certificateless authenticated searchable encryption with multi-trapdoor indistinguishability (MTP-IND) guarantees

With the rapid growth of the internet of things (IoT), resource-constrained devices have become an integral part of our daily lives. Public key encryption with keyword search (PEKS) enables users to search over encrypted data without revealing sensitive information. However, the computational and memory constraints of these devices pose challenges for implementing PEKS. Additionally, most of the existing schemes are either vulnerable to attacks like keyword guessing attacks, or they rely on bilinear-pairing operations that make them inefficient for resource-constrained devices, or both. To address these issues, we propose a lightweight and pairing-free certificateless authenticated searchable encryption scheme with multi-trapdoor guarantees for resource-constrained devices. Our scheme embeds a shared key in the ciphertext and in the trapdoor that is computable by both the sender and the receiver to ensure authentication and protection against keyword guessing attacks. We also make the trapdoor generation probabilistic to eliminate the need for a secure channel when transmitting the trapdoor, hence, achieving multi-trapdoor indistinguishability. Furthermore, we employ regular cryptography operations instead of bilinear-pairing operations to support deployment on resource-constrained devices. Our scheme is efficient, secure, and outperforms other compared schemes in terms of security guarantees, computational costs, and communication overhead.