Cross-domain heterogeneous signcryption with keyword search for wireless body area network

The Wireless body area network (WBAN) is a network composed of sensors communicating through wireless technology, these sensors can capture and encrypt the physiological data of the human body and transmit it to a remote cloud server for use by authorized users. However, how to retrieve and obtain the encrypted data has become a problem that must be solved. Nowadays, searchable encryption with keywords (SEK) is a widely used technology to solve this problem. Nevertheless, there are some problems that need to be noted. First, SEK is vulnerable to keyword guessing attack (KGA) and inside keyword guessing attack (IKGA). Second, since the sender and receiver are likely to work under different cryptosystems, the designed scheme should satisfy heterogeneity. Third, the communication parties in heterogeneous domain usually use different cryptographic system parameters, achieving cross-domain authentication between these communication parties can greatly improve the practicability of the scheme. To address these issues, we put forward a new searchable signcryption scheme for WBAN. Under the complexity of computational assumptions, the proposed scheme is proved to simultaneously achieve ciphertext indistinguishability, trapdoor indistinguishability, ciphertext unforgeability and the resistance of KGA and IKGA in the random oracle model (ROM). Further, our scheme allows the WBAN sensors in the certificateless public key cryptography (CLC) environment and the receivers in the public key infrastructure (PKI) environment to realize cross-domain authentication and heterogeneous communication. Compared to the five existing schemes, the total computation cost of our scheme is reduced by at least 59.99%.