Advances in Authentication, Authorization and Privacy for Securing Smart Communications

1. Introduction

Recent advancements in wireless communication systems have facilitated the development of cutting-edge applications in modern architecture, and these systems are rapidly transforming our daily activities and enabling critical industrial processes [1,2,3]. Additionally, the ubiquity of commercial 5G wireless systems and the current aggressive research in beyond 5G and 6G wireless networks have facilitated the development of various innovative technologies, enabling the creation of a smart society [4,5,6,7]. However, these critical applications are often transmitted over open wireless channels, which require robust security architectures to protect sensitive user information. This calls for secure and efficient authentication, authorization, and accounting mechanisms to address the escalating issues of wireless network security vulnerability and other concerns related to security and privacy. Existing cryptographic methods can indeed be constrained by several factors, particularly in environments with limited resources, which tends to limit their processing, security, and communication capabilities [8,9,10,11,12,13].

In terms of processing constraints, most cryptographic algorithms, such as Rivest–Shamir–Adleman (RSA), Elliptic Curve Cryptography (ECC), and Advanced Encryption Standard (AES), require enormous processing power for key generation, encryption, and decryption. Additionally, it can be challenging to process complex cryptographic operations in most resource-constrained devices, such as Internet of Things (IoT) sensors, embedded systems, and smart cards, among others. Another point worth mentioning is that most cryptographic operations incur delays, which limits their usefulness for real-time applications. In terms of security constraints, key management and physical attacks may pose serious issues. The primary challenges lie in securely and safely generating, distributing, and storing cryptographic keys in decentralized environments. Also, devices with limited hardware protection could be vulnerable to various forms of attacks. Some traditional systems employ insecure cryptographic schemes, rendering them vulnerable to multiple attacks.

Similarly, the communication constraints are based on bandwidth overhead, protocol complexity, and energy consumption. Cryptographic algorithms tend to increase message size with the presence of headers and encryption metadata, overworking communication channels with low bandwidth. Additionally, low-latency networks often struggle to execute secure communication, which typically involves multi-step handshakes. Lastly, the vast energy resource requirements in encrypting and transmitting secure data are critical issues that need to be addressed.

Moreover, a trade-off exists between privacy and authentication, or between security and performance, in traditional authentication mechanisms [14,15,16,17]. There is a lack of sufficient research that addresses these security and privacy concerns holistically. Currently, lightweight cryptography, post-quantum cryptography, hardware acceleration, and hybrid protocols that integrate symmetric and asymmetric methods are being leveraged to address these concerns. To address these issues proactively, this Special Issue presents novel contributions in the domain of secure and anonymous designs for smart communication systems. New cryptographic algorithms and protocols, including cutting-edge authentication and authorization schemes, as well as innovative accounting mechanisms, are presented. Additionally, applied cryptographic designs, including post-quantum cryptography, lightweight cryptography, cryptographic verification solutions, smart identification mechanisms, new digital signature-assisted smart communication systems, and smart digital certificate-based communication schemes are demonstrated and elaborated extensively.

2. Contributions

The Special Issue presents eleven original contributions from world-class researchers. These contributions provide viable solutions to address critical security and privacy challenges in smart communications. These are briefly described as follows.

In Contribution 1, AlJanah et al. optimize group multi-factor authentication for secure and efficient communication among Internet of Things (IoT) devices. The paper reports an extension to an existing authentication framework that facilitates the multi-factor authentication of devices in device-to-device and device-to-multidevice interactions. Specifically, the authors introduce four authentication protocols to enable multi-factor group authentication among IoT devices. In general, results indicate that the protocols satisfy the specified security requirements and provide resiliency against authentication-related attacks. Furthermore, the communication and computation overheads of the protocols compared favorably with those of IoT group authentication solutions and Kerberos.

Lin et al. (Contribution 2) propose a quantum key distribution for securing smart grids, enabling entities within a secure group to encrypt and authenticate user data belonging to individual entities, thereby guaranteeing the security and privacy of communication channels and transmitted data.

In the work of Ou et al. (Contribution 3), a self-sovereign identity (SSI) blockchain framework for access control and transparency in financial institutions is presented. The SSI enables customers to determine who has access to and uses their data, thereby ensuring higher levels of privacy preservation without relying on a centralized server for control of user information. The SSI server allows customers to securely store and access their assets and credit data on the blockchain, thereby reducing unnecessary risks.

In Contribution 4, Lizama-Pérez developed a matrix multiplication approach for quantum-safe cryptographic systems, including public key exchange, user authentication, digital signatures, blockchain integration, and homomorphic encryption. The application of matrix factorization reinforces the proposed scheme, improving its resistance to current quantum cryptanalysis techniques. The proposed method preserves confidentiality by enabling secure communication while guaranteeing user authentication using public key validation.

Aziz et al. (Contribution 5) examine the efficacy of next-generation block ciphers, focusing on achieving superior memory efficiency and cryptographic robustness for Internet of Things (IoT) devices. In particular, the work presents an advanced design of lightweight block ciphers that enhances traditional dynamic permutations with innovative randomized substitutions. Test results suggest that the proposed algorithm maintains strong cryptographic properties with randomized substitutions and outperforms existing models in several critical aspects.

Chang et al. (Contribution 6) conduct an extensive cryptanalysis of dual-stage permutation encryption using a large-kernel convolutional neural network and a known-plaintext attack and suggest two cryptanalysis schemes leveraging a large-kernel convolutional neural network and a known-plaintext attack. Experimental results indicate that the reported cryptanalysis schemes can break the dual-stage permutation encryption scheme, attesting to their superiority over the baseline schemes.

In Contribution 7, Kuznetsov et al. evaluate the security of Merkle trees, focusing on the analysis of data falsification probabilities for applications in blockchain and Internet of Things (IoT). The authors developed a theoretical framework to calculate the likelihood of data falsification, taking into account the length of the Merkle path and the hash length. Simulations with diverse hash lengths and Merkle path lengths show a decrease in falsification probability with increasing hash length and an inverse relationship with longer Merkle paths.

Similarly, in Contribution 8, Kuznetsov et al. present a novel proof aggregation approach based on OR logic, which enables the generation of compact and universally verifiable proofs for Merkle tree inclusion. The study highlights the significant limitations of traditional proof aggregation techniques based on AND logic, which suffer from high verification complexity and huge data communication overhead. In comparison to the AND aggregation, which requires the verifier to process all leaf hashes, the OR composition from Sigma protocols enables achieving a proof size that is independent of the number of leaves in the tree, allowing verification to be performed using any single valid leaf hash. Last, the authors suggest the potential of combining OR and AND aggregation logics to create complex acceptance functions, enabling the development of expressive and efficient proof systems for various blockchain applications.

Kuznetsov et al. (Contribution 9) focus on enhancing the security of smart communication by employing a novel cost function for generating efficient substitution boxes (S-boxes) in symmetric key cryptography. Specifically, a new cost function is introduced that significantly reduces generation complexity, lowering the iteration count to under 50,000 for achieving the desired S-box. These boxes facilitate the attainment of confusion and diffusion properties in substitution–permutation networks. The authors emphasize that these properties are imperative to statistical, differential, linear, and other forms of cryptanalysis, and they are equally crucial in pseudorandom number generation and cryptographic hashing algorithms.

The work of Kabil et al. (Contribution 10) focuses on a cryptanalysis of two conditional privacy-preserving authentication schemes for vehicular ad hoc networks (VANETs). The authors deployed conditional privacy-preserving authentication (CPPA) schemes to secure communications in VANETs, aiming to meet specific critical requirements, including user privacy and accountability. The work cryptanalyzes Zhang’s CPPA scheme [18] for VANET security (PA-CRT), which is based on identity batch verification (IBV) and the Chinese Remainder Theorem (CRT) [19], as reported in 2019. Additionally, it analyzes Xiong’s scheme [20] from 2021 and the Tao scheme [21], reported in 2023. Furthermore, the authors provided a detailed analysis of the causes and countermeasures by identifying the vulnerabilities in each scheme.

Lastly, Ramesh et al. (Contribution 11) present a novel and secure fake modulus-based Rabin-Ӡ cryptosystem to safeguard sensitive data, such as credit card numbers, personal identification, and financial records, from unauthorized access. In particular, the work proposes a new method that introduces the concept of fake modulus during encryption. A fake modulus was introduced to enhance the security of the Rabin cryptosystem during encryption, and this fake modulus confuses attackers when attempting to factorize the public key. Performance evaluation indicates that the proposed system is more robust against attacks compared to several baseline approaches.

3. Conclusions and Future Scope

This Special Issue presents recent contributions concerning advances in authentication, authorization, and privacy for securing smart communications. The Special Issue comprises eleven research articles that address critical problems in this domain, ranging from vulnerability discovery and intrusion detection and mitigation to cryptographic analysis, three-factor authentication, and emerging security applications. Overall, these contributions will facilitate advanced research and development initiatives in the vast domain of security and privacy toward enabling smart and secure communications for a smart society.