If a wireless sensor network (WSN) is integrated into the Internet as a part of the Internet of things (IoT), there will appear new security challenges, such as setup of a secure channel between a sensor node and an Internet host. In this paper, we propose a heterogeneous online and offline signcryption scheme to secure communication between a sensor node and an Internet host. We prove that this scheme is indistinguishable against adaptive chosen ciphertext attacks under the bilinear Diffie-Hellman inversion problem and existential unforgeability against adaptive chosen messages attacks under the q-strong Diffie-Hellman problem in the random oracle model. Our scheme has the following advantages. First, it achieves confidentiality, integrity, authentication, and non-repudiation in a logical single step. Second, it allows a sensor node in an identity-based cryptography to send a message to an Internet host in a public key infrastructure. Third, it splits the signcryption into two phases: i) offline phase; and ii) online phase. In the offline phase, most heavy computations are done without the knowledge of a message. In the online phase, only light computations are done when a message is available. Our scheme is very suitable to provide security solution for integrating WSN into the IoT.

Wireless sensor network (WSN) plays an important role in military sensing and tracking, target tracking, and environment monitoring. To query of the network to get useful information from anywhere and anytime, we need to integrate the WSN into the Internet as part of the Internet of Things (IoT). In this case, it is an important task to design an access control scheme that can authorize, authenticate and revoke a user to access the WSN. In this paper, we propose a heterogeneous signcryption scheme to control the access behavior of the users. We give the formal security proof of our scheme in the random oracle model. An important characteristic of our scheme is to allow a user in a certificateless cryptography (CLC) environment to send a message to a sensor node in an identity-based cryptography (IBC) environment. We give an access control scheme for the WSN in the context of the IoT using the proposed signcryption scheme. As compared with existing two access control schemes using signcryption, the computational cost of sensors in our scheme is reduced by about 22% and 53%, respectively and the energy consumption of sensors in our scheme is reduced by about 33% and 54%, respectively

Vehicular ad hoc networks (VANETs) ensure improvement in road safety and traffic management by allowing the vehicles and infrastructure that are connected to them to exchange safety messages. Due to the open wireless communication channels, security and privacy issues are a major concern in VANETs. A typical attack consists of a malicious third party intercepting, modifying and retransmitting messages. Heterogeneous vehicular communication in VANETs occurs when vehicles (only) or vehicles and other infrastructure communicate using different cryptographic techniques. To address the security and privacy issues in heterogeneous vehicular communication, some heterogeneous signcryption schemes have been proposed. These schemes simultaneously satisfy the confidentiality, authentication, integrity and non-repudiation security requirements. They however fail to properly address the efficiency with respect to the computational cost involved in unsigncrypting ciphertexts, which is often affected by the speeds at which vehicles travel in VANETs. In this paper, we propose an efficient conditional privacy-preserving hybrid signcryption (CPP-HSC) scheme that uses bilinear pairing to satisfy the security requirements of heterogeneous vehicular communication in a single logical step. Our scheme ensures the transmission of a message from a vehicle with a background of an identity-based cryptosystem (IBC) to a receiver with a background of a public-key infrastructure (PKI). Furthermore, it supports a batch unsigncryption method, which allows the receiver to speed up the process by processing multiple messages simultaneously. The security of our CPP-HSC scheme ensures the indistinguishability against adaptive chosen ciphertext attack (IND-CCA2) under the intractability assumption of q-bilinear Diffie-Hellman inversion (q-BDHI) problem and the existential unforgeability against adaptive chosen message attack (EUF-CMA) under the intractability assumption of q-strong Diffie-Hellman (q-SDH) problem in the random oracle model (ROM). The performance analysis indicates that our scheme has an improvement over the existing related schemes with respect to the computational cost without an increase in the communication cost.