The Internet of Things (IoT) is revolutionizing our modern lives by introducing active connection between smart devices. However, IoT devices are repeatedly exhibiting many security flaws, which will inevitably lead to eavesdropping and impersonation attacks. Thus, providing a proper security in IoT becomes a prime focus for the researchers. In cryptography, certificateless signcryption (CLSC) is one of the recent public key techniques for the security requirements of the authenticity and confidentiality of any message between the parties. In this work, a new generalized CLSC (gCLSC) is introduced to provide the functions of digital signature and encryption to fulfill the authenticity and confidentiality for the resource-constrained IoT devices. Besides, the gCLSC supports the property of public verifiability and security of an ideal signcryption under the strong Diffie-Hellman and bilinear Diffie-Hellman inversion problems without random oracle model. Performance assessment of the gCLSC gives satisfactory results after comparing with other competitive CLSC schemes in terms of its functionality. Therefore, the gCLSC can be adopted in the IoT networks where authenticity, confidentiality, and lightweight are the essential factors.

In-vehicle communications are not designed for message exchange between the vehicles and outside systems originally. Thus, the security design of message protection is insufficient. Moreover, the internal devices do not have enough resources to process the additional security operations. Nonetheless, due to the characteristic of the in-vehicle network in which messages are broadcast, secure message transmission to specific receivers must be ensured. With consideration of the facts aforementioned, this work addresses resource problems by offloading secure operations to high-performance devices, and uses attribute-based access control to ensure the confidentiality of messages from attackers and unauthorized users. In addition, we reconfigure existing access control based cryptography to address new vulnerabilities arising from the use of edge computing and attribute-based access control. Thus, this paper proposes an edge computing-based security protocol with fine-grained attribute-based encryption using a hash function, symmetric-based cryptography, and reconfigured cryptographic scheme. In addition, this work formally proves the reconfigured cryptographic scheme and security protocol, and evaluates the feasibility of the proposed security protocol in various aspects using the CANoe software.

Due to the higher density of mobile devices is expected, the fifth generation (5G) mobile networks introduce small cell networks (SCNs) to prevent exhausting radio resources. SCNs improve radio spectrum utilization by deploying more base stations (BSs) in the networks. Even though, authenticated key exchange (AKE) is still essential to ensure entity authentication and confidentiality in mobile communications. Besides, user anonymity is required to guarantee the footprints of mobile communications being concealed. However, AKE with user anonymity may increase the latency of communications dramatically in total due to several times more frequency in SCNs. The increase of latency will be more serious when an AKE protocol supports user anonymity, where traceability and revocability to users are necessary. Thus, this work presents a secure region-based handover scheme (ReHand) with user anonymity and fast revocation for SCNs. ReHand greatly reduces the communication latency when user equipments (UEs) roam between small cells within the region of a macro base station, i.e., eNB, and the computation costs due to the employment of symmetry-based cryptographic operations. Compared to the three related prior arts, ReHand dramatically reduces the latency from 82.92% to 99.99% by region-based secure handover. Nevertheless, this work demonstrates the security of ReHand by theoretically formal proofs.

Hyperledger Fabric (HLF), one of the most popular permissioned blockchains, has recently received attention for blockchain-enabled Internet of Things (IoT). However, for IoT applications to handle time-sensitive data, the processing latency in HLF has emerged as a new challenge. In this article, therefore, we establish a practical HLF latency model for HLF-enabled IoT. We first discuss the structure and the transaction flow of HLF-enabled IoT. After implementing real HLF, we capture the latencies that each transaction experiences and show that the total latency of HLF can be modeled as a Gamma distribution, which is validated by conducting a goodness-of-fit test (i.e., the Kolmogorov-Smirnov (KS) test). We also provide the parameter values of the modeled latency distribution for various HLF environments. Furthermore, we explore the impacts of three important HLF parameters including the average transaction generation rate, block size, and block-generation timeout on the HLF latency. As a result, this article provides design insights on minimizing the average latency for HLF-enabled IoT.

As advanced V2X applications emerge in the connected and autonomous vehicle (CAV), the data communications between in-vehicle end-devices and outside nodes increase, which make the end-to-end (E2E) security to in-vehicle end-devices as the urgent issue to be handled. However, the E2E security with fine-grained access control still remains as a challenging issue for resource-constrained end-devices since the existing security solutions require complicated key management and high resource consumption. Therefore, this paper proposes a practical and secure vehicular communication protocol for the E2E security based on a new attribute-based encryption (ABE) scheme. In the ABE scheme, the outsourced computation is provided for encryption, and the computation cost for decryption constantly remains small, regardless of the number of attributes. The policy privacy can be ensured by the proposed ABE to support privacy-sensitive V2X applications, and the existing identity-based signature for outsourced signing is newly reconstructed. The protocol achieves the confidentiality, message authentication, identity anonymity, unlinkability, traceability, and reconfigurable outsourced computation, and this paper also shows the practical feasibility of the protocol via the performance evaluation.