Existing conditional anonymous authentication protocols to secure the group communication in VANETs (Vehicular Ad hoc Networks) render challenges such as dynamically updating membership in a domain and achieving vehicle user's privacy preservation. This paper elegantly addresses these challenges by proposing a novel conditional privacy-preserving authentication with dynamic membership for VANETs depending on chinese remainder theorem (CRT). Specifically, the CRT is utilized by a trusted authority to securely disseminate a domain key for the authorized vehicles in the same domain, where each vehicle in this domain is able to obtain the domain key by only performing one modulo division operation in case of domain key updating. Distinct from the previous works in this field, our proposed protocol not only achieves message authentication, anonymity and conditional privacy-preserving, but also provides forward security and backward security of vehicles. Theoretical analysis and experiment simulation demonstrate that the proposed protocol is provably secure and highly feasible.

The existing signcryption schemes with equality testing are aimed at a sole cryptosystem and not suitable for the sophisticated heterogeneous network of Industrial Internet of Things (IIoT). To deal with this challenge, we propose a heterogeneous signcryption scheme with equality test (HSC-ET) in this article. This scheme enables a sensor in public key infrastructure (PKI) to execute data encryption and deliver it to the semitrusted entity (cloud server). When a user in an identity-based cryptosystem (IBC) intends to search for some data stored on the cloud server. The delegated cloud server executes tests on ciphertexts for determining whether the same underlying plaintext exists between two ciphertexts. These two ciphertexts can be one signcrypted ciphertext and one encrypted ciphertext, or both encrypted/signcrypted ciphertext, thus achieving a flexible search to the ciphertext. HSC-ET is demonstrated to be secure by the rigorous and detailed analysis. The experimental simulation and analysis results show the efficiency of our scheme.

With the continuous development of the industrial Internet of Things (IIoT), many organizations opt for storing the data collected by smart devices on a cloud server for saving costs. Considering the untrusted nature of the communication channel, how to ensure the authenticity of data is an urgent matter to be solved. Certificateless signatures that can provide an authentication mechanism for the data seem to be a viable option to this problem. Nevertheless, the certificateless signature scheme proposed so far is either easy to be broken or inefficient. In this paper, a pairing-free and provably secure certificateless parallel key-insulated signature (CL-PKIS) scheme is put forward for securing the communication in the IIoT environment. Unlike previous work in this field, our scheme not only uses elliptic curves to maintain higher efficiency, but also implants key-insulated primitive to reduce the risk of key exposures. Besides, our scheme provides a parallel mechanism to make it more suitable for the IIoT environment, which was not available in previous solutions. Finally, the security of our CL-PKIS scheme is proved under the discrete logarithm assumption in the random oracle model.

The signcryption protocols supporting the equality test are only for a single system rather than a flexible heterogeneous environment of wireless body area networks (WBANs). In this article, this problem is efficiently addressed through a proposed heterogeneous signcryption scheme from identity-based cryptosystem (IBC) to public key infrastructure (PKI) with an equality test (HSCIP-ET) for WBANs. Our scheme allows the sensors planted or worn by a user in the IBC system to signcrypt sensitive data using the public key of the management center in the PKI system, and then uploading it to the cloud server. Subsequently, the equality test can be executed by the cloud server on diverse ciphertexts to determine whether they contain the identical plaintext and return the corresponding result after receiving a request from an application provider. Furthermore, a rigorous analysis and an experimental comparison demonstrate the security and efficiency of the HSCIP-ET approach, respectively.

Vehicular platooning is emerging as a promising method that can enhance road utilization, alleviate traffic congestion and even decrease energy expenditure by shortening the distance between vehicles in the platoon. In platooning, a platoon leader (PL) is required to communicate with platoon members (PMs) to issue instructions. In this way, the PMs are simply expected to follow the command and enjoy their free time. However, when the same instruction is sent to different PMs in the form of single-hop unicast, the ciphertext will go up as the quantity of PMs in the platoon resulting in a dramatic increase in transmission time. Moreover, transmission instructions without security and authentication guarantees are easily intercepted, forged or deleted. Therefore, we propose BSPC, a broadcast signcryption scheme for platoon communication based on identity. In our BSPC, with only one signcryption, the PL can generate a public verifiable ciphertext with fixed-length for PMs, while employing broadcast functionality to deliver the ciphertext to multiple PMs at once. In such a manner, the confidentiality, integrity and authentication of transmitted commands are ensured, such that malicious vehicles cannot manipulate data and unauthorized vehicles have no way to access it. Besides, the instructions' transmit time is greatly reduced. Our BSPC proposal is proved to be secure and unforgeable through rigorous analysis. Furthermore, simulation results demonstrate our BSPC is practical and efficient for platoon communication.

Vehicular crowdsensing (VCS) has aroused extensive attention because of its ability to provide comprehensive data services for intelligent transportation systems. Wherein, secure data transmission is a prerequisite for realizing the above benefits of VCS. Unfortunately, although many works on secure data sharing have been proposed, these schemes suffer from practical weaknesses such as data source authentication, malicious identity traceability, and inefficiency. In this paper, we propose a practical conditional anonymization and leakage-resilient authentication solution for vehicular crowdsensing communication (CALRA). Our proposal not only resists the leakage of sensitive information about vehicles but also realizes the authentication of data senders, while guaranteeing the integrity, authenticity, and confidentiality of data. Besides, CALRA exploits traceability technology to pursue malicious/illegal participants, thus avoiding participants’ accountability evasion caused by absolute anonymity. Furthermore, our CALRA solution delegates complex computational processes into an offline formulation to reduce computational and communication overheads. Finally, our scheme is proved to be secure and unforgeable through the random oracle model, and the performance evaluation illustrates that our CALRA proposal is superior and practical.