Certificateless Aggregate Signature Scheme Research Articles

IPCAS: An improved conditional privacy-preserving certificateless aggregate signature scheme without bilinear pairing for VANETs

Recently, Gong et al. proposed a Certificateless Aggregate Signature (CLAS) scheme (shorted by PCAS) with conditional privacy-preserving without bilinear pairing for Vehicular Ad-hoc Networks (VANETs). Unfortunately, after analyzing security, the PCAS scheme fails to satisfy the necessary unlinkability in VANETs and is vulnerable to the public key replacement forgery attack of the Type-I adversary. Subsequently, this article analyses the causes of these two security issues in detail and proposes an improved CLAS scheme for VANETs (called IPCAS). Through security analysis, this article proves that the IPCAS is existentially unforgeable under the adaptive chosen message attacks against Type-I and Type-II adversaries in the random oracle model, and satisfies the necessary security and privacy requirements in VANETs, including unlinkability. Finally, the performance analysis results show that compared to PCAS for single message and n aggregate messages (n=1000), the computational overhead of IPCAS is reduced by 20.01% and 49.08% respectively, and the communication overhead is reduced by 18.75% and 28.14% respectively. Therefore, IPCAS not only makes up for the security vulnerabilities of PCAS but also has better performance.

DRCLAS: An efficient certificateless aggregate signature scheme with dynamic revocation in vehicular ad-hoc networks

The emergence of the Vehicular Ad-hoc Networks (VANETs) has greatly enhanced the efficiency and safety of transportation systems. However, due to the dynamicness and openness of vehicular networks, it is vulnerable for VANETs to confront various security threats. The dissemination of disinformation and the occurrence of attacks within these networks can result in severe damage and compromise the overall security of transportation systems. To mitigate such challenges, this paper presents an efficient certificateless aggregate signature scheme with dynamic revocation in VANETs. Taking use of the early-stopping factorial bitwise divisions (EFBD) algorithm, it achieves the invalid signatures tracking, and revokes the malicious vehicles dynamically. In addition, by combining the fingerprint counting bloom filter (FP-CBF), the trust assessment mechanism and the cloud server, it enables the vehicle to remedy its incorrect signatures. At last, through the comprehensive security and performance analysis, it demonstrates that this protocol enjoys improved communication security and computational efficiency.

An NTRU-Based Certificateless Aggregate Signature Scheme for Underwater Acoustic Communication

An NTRU-Based Certificateless Aggregate Signature Scheme for Underwater Acoustic Communication

Cryptanalysis of Two Conditional Privacy Preserving Authentication Schemes for Vehicular Ad Hoc Networks

Conditional Privacy Preserving Authentication (CPPA) schemes are an effective way of securing communications in vehicular ad hoc networks (VANETs), as well as ensuring user privacy and accountability. Cryptanalysis plays a crucial role in pointing out the vulnerabilities in existing schemes to enable the development of more resilient ones. In 2019, Zhang proposed a CPPA scheme for VANET security (PA-CRT), based on identity batch verification (IBV) and Chinese Remainder Theorem (CRT). In this paper, we cryptanalyze Zhang’s scheme and point out its vulnerability to impersonation and repudiation attacks. In 2023, Zhang’s scheme was cryptanalyzed by Tao; however, we point out flaws in Tao’s cryptanalysis due to invalid assumptions; hence, we propose countermeasures to Tao’s attacks. Furthermore, in 2021, Xiong proposed a Certificateless Aggregate Signature (CLAS) scheme which is also cryptanalyzed in this paper. Finally, we analyze the causes and countermeasures by pointing out the vulnerabilities in each scheme that enabled us to launch successful attacks and proposing changes that would fortify these schemes against similar attacks in the future.

Certificateless Aggregate Signature Scheme With Security Proofs in the Standard Model Suitable for Internet of Vehicles

Certificateless Aggregate Signature Scheme With Security Proofs in the Standard Model Suitable for Internet of Vehicles

Comments on "A Conditional Privacy-Preserving Certificateless Aggregate Signature Scheme in the Standard Model for VANETs"

Comments on "A Conditional Privacy-Preserving Certificateless Aggregate Signature Scheme in the Standard Model for VANETs"

An efficient and secure certificateless aggregate signature scheme

In recent years, the Internet of Things (IoT) has been developing rapidly and popularizing the world. Smart home is one of its important applications, the devices and household appliances are connected together through the network to provide intelligent services. However, malicious attacks often occur during the transmission of data information, resulting in data leakage or data changes. Therefore, it is necessary to ensure the integrity and availability of data. Based on this, we propose a new pairing-free certificateless aggregate signature (CLAS) scheme, which achieves efficient authentication of multiple messages and improves the verification rate. In addition, we demonstrate its security based on the hardness of the elliptic curve discrete logarithm problem in the random oracle model. Comparison with other CLAS schemes proves that our scheme has better security and higher efficiency through performance analysis.

A lattice-based unordered certificateless aggregate signature scheme for cloud medical health monitoring system

A lattice-based unordered certificateless aggregate signature scheme for cloud medical health monitoring system

A Blockchain-Based Certificateless Aggregate Signature Scheme for Fog-Enabled Smart Grid Environment

The smart grid-based power grid systems face many challenges like-higher computational power requirements, higher latency, security and privacy issues, and single point of failure. In the power grid systems, multiple distribution centers are responsible for supplying electricity in an area. Thus, to address the issues such as single point of failure and higher latency, this paper integrates fog computing and blockchain into the smart grid utilizing distribution centers as blockchain peers and proposes a distributed smart grid environment. Moreover, to address the security and privacy issues, the existing signature schemes face issues like-certificate management, key escrow, higher computational cost, etc. Therefore, this paper employs a certificateless approach and proposes a blockchain-based certificateless aggregate signature scheme that provides authentication, integrity, and privacy in the proposed smart grid environment. Next, a thorough security analysis has been done to prove the security strength of proposed scheme against different types of attackers and attacks. Finally, the performance analysis based on Hyperledger Fabric and cryptography libraries proves the computational and communication efficiency of the proposed scheme.

A Security-Enhanced Certificateless Conditional Privacy-Preserving Authentication Scheme for Vehicular Ad Hoc Networks

By adopting advanced Internet of Things (IoT) technology to sense and collect traffic-related information to improve traffic safety and efficiency, the vehicular ad hoc network (VANET) is becoming a prominent application that changes human driving experiences in the current era. Because frequent data exchange occurs in open environments, VANETs are inherently vulnerable to security and privacy attacks. In history, many certificateless aggregate signature (CLAS) schemes with conditional privacy-preserving (CPP) have been proposed to ensure the authenticity and integrity of the exchanged data and protect users’ privacy. However, we reveal that the state-of-the-art schemes cannot be deployed in practical VANET applications by proposing concrete signature forgery attacks. To this end, we propose a new CLAS-based authentication scheme with CPP for VANETs. The rigorous security proofs based on the standard cryptographic assumption show that the scheme has enhanced security. Moreover, theoretical analysis and experimental evaluation illustrate the practicality of our design.

A Security-Enhanced Pairing-Free Certificateless Aggregate Signature for Vehicular Ad-Hoc Networks

As self-organizing, highly heterogeneous and multi-interactive networks, vehicular ad-hoc networks (VANETs) are rapidly improving the efficiency of modern traffic. This promising technology is significant for supporting current intelligent transportation by cooperative data sharing and processing. Considering requirements for secure interactions and the limitation of resources in VANETs, protecting data authenticity while enhancing computational efficiency has become the main challenge. A certificateless aggregate signature (CLAS) can not only ensure data security, but also reduce communication costs, which is suitable for a resource-constrained environment. However, most existing CLAS schemes either own serious security vulnerabilities or result in tremendous computational overhead. In this article, we propose an efficient, privacy-preserving, and pairing-free CLAS scheme with enhanced security. We prove that it is existentially unforgeable against adaptive chosen message attacks in the random oracle model. Performance evaluation illustrates that our proposed scheme is more appropriate to the VANETs scenario.

A redesigned secure and efficient data transaction protocol for mobile payment system

Generally, the secure protocol was proposed from the certificateless signature (CLS) scheme to provide the corresponding security for the actual application. However, for the previous application protocols, most of the underlying CLS schemes cannot have their claimed security, because some proposals cannot resist forgery attacks or the master secret key can be captured by the probabilistic polynomial time adversary. To further address the above problems, we take several previous CLS schemes as instances to make a detailed analysis of the causes of the above security flaws and point out that, in a secure CLS scheme, we should appropriately publish the public parameters. Based on the above analysis, we design an efficient and secure CLS scheme in this paper, and the unforgeability is proved based on the hardness of discrete logarithm complexity assumption through the Forking lemma. Compared with the existing constructions, our new proposal has advantages in communication and computation efficiency but also has higher security. Furthermore, a concrete construction of a certificateless aggregate signature (CLAS) scheme is designed with the above basic CLS scheme to realize efficient verification of multiple signatures. Finally, we further improve the key conditions that need to be paid attention to design a secure CLS scheme.

An Efficient and Secure Certificateless Aggregate Signature Scheme for Vehicular Ad hoc Networks

Vehicular ad hoc networks (VANETs) have become an essential part of the intelligent transportation system because they provide secure communication among vehicles, enhance vehicle safety, and improve the driving experience. However, due to the openness and vulnerability of wireless networks, the participating vehicles in a VANET system are prone to a variety of cyberattacks. To secure the privacy of vehicles and assure the authenticity, integrity, and nonrepudiation of messages, numerous signature schemes have been employed in the literature on VANETs. The majority of these solutions, however, are either not fully secured or entail high computational costs. To address the above issues and to enable secure communication between the vehicle and the roadside unit (RSU), we propose a certificateless aggregate signature (CLAS) scheme based on hyperelliptic curve cryptography (HECC). This scheme enables participating vehicles to share their identities with trusted authorities via an open wireless channel without revealing their identities to unauthorized participants. Another advantage of this approach is its capacity to release the partial private key to participating devices via an open wireless channel while keeping its identity secret from any other third parties. A provable security analysis through the random oracle model (ROM), which relies on the hyperelliptic curve discrete logarithm problem, is performed, and we have proven that the proposed scheme is unforgeable against Type 1 (FGR1) and Type 2 (FGR2) forgers. The proposed scheme is compared with relevant schemes in terms of computational cost and communication overhead, and the results demonstrate that the proposed scheme is more efficient than the existing schemes in maintaining high-security levels.

Cryptanalysis of Two Privacy-Preserving Authentication Schemes for Smart Healthcare Applications

Ensuring the secure sharing of privacy-sensitive healthcare data is attracting considerable interest from researchers. Recently, Ogundoyin et al. designed a lightweight privacy-preserving authentication scheme named PAASH for smart health applications. Benil et al. proposed a public verification and auditing scheme named ECACS for securing e-health systems. Ogundoyin et al. and Benil et al. proposed an efficient certificateless aggregate signature (CLAS) scheme as their respective foundation signature schemes. They declared that their constructions were provably secure under the hardness assumption of cryptographic problems. In this work, we disprove their claim by analyzing the correctness and security of their underlying CLAS schemes. We first show that the batch verification process of n signatures for the CLAS scheme in PAASH is incorrect, and any public-key replacement attacker can easily break the scheme. We analyze the reasons for our attack and propose an improved scheme, named PAASH+. We then show that the CLAS scheme in ECACS fails to achieve correctness, an essential property that a cryptographic scheme should provide. As a result, it is impractical to deploy the designed PAASH and ECACS constructions in any real smart health applications.

An Efficient Identity Authentication Scheme With Dynamic Anonymity for VANETs

Nowadays, as an essential technique for intelligent transportation, Vehicular Ad hoc Networks (VANETs) has significantly improved people’s travel experience, providing richer and smarter services for vehicles while ensuring driver safety. However, considering that VANETs are complex, some security challenges still remain, including but not restricted to privacy preserving of vehicles, authentication of messages, limited resources in computational power and network bandwidth. To address these issues, many privacy-preserving identity authentication schemes for VANETs have been proposed recently. However, these schemes still suffer some limitations. First, their computational overheads are heavy due to the complex calculations. Second, some schemes are vulnerable to various security weaknesses, unable to resist normal attacks. Third, in some schemes, the same pseudonym keeps unchanged and it is linked to the corresponding private key of user. The consequence is that if the user wants to change its pseudonym, the corresponding private key must be changed. In order to further solve the above problems, we propose a novel privacy-preserving identity authentication protocol based on certificateless aggregate signature scheme, allowing the user to generate a fuzzy identity to hide her real identity, and the private key can be kept unchanged even if the corresponding pseudonym is updated. Furthermore, to achieve efficiency in computation, bilinear mapping is avoided in our proposed scheme. We prove that our protocol satisfies unforgeability in the random oracle based on a classic complexity assumption. Finally, the security and efficiency analyses demonstrate that our construction enjoys more security features and better performance compared with the existing schemes.

PCAS: Cryptanalysis and improvement of pairing-free certificateless aggregate signature scheme with conditional privacy-preserving for VANETs

Certificateless aggregate signature (CLAS) is an effective approach for the multiple authentications in multi-users and multi-information environments like the vehicular ad hoc networks (VANETs), which can address the certificate management issue in the traditional public key cryptography (PKC) and solve the key escrow problem in identity-based cryptography (IBC). In recent years, a new CLAS mechanism (LICLAS) is presented for the authentication of sensors in healthcare wireless medical sensor networks (HWMSNs). In this paper, we make an analysis and prove that LICLAS is not able to against forgery attacks. Thus, we present an improved CLAS scheme (PCAS) for vehicle authentication in VANETs, which satisfies the privacy and security requirements. PCAS constructs the signature algorithm based on Elliptic Curve Cryptography (ECC) to avoid bilinear pairing and Map-to-Hash function operations. In order to further improve security and efficiency of PCAS, the vehicle key generation and signature algorithm is revised. The pseudonym mechanism is also adopted to achieve conditional privacy preservation. Besides, PCAS allows to execute a batch verification of messages, where RSUs may verify the aggregated signatures from vehicles to reduce time overhead. Under the assumption that the elliptic curve discrete logarithm problem (ECDLP) is hard, PCAS is proved to be existentially unforgeable against adaptive chosen message attacks in the random oracle model. Through the performance analysis, under the same time complexity, PCAS is shown to more effective. Compared with LICLAS, for a single message and 2000 messages, the transmission overhead of PCAS is reduced by 25% and 25% respectively, and the computation overhead is reduced by 16.56% and 25.34% respectively.

Analysis and Improvement of an Efficient Certificateless Aggregate Signature With Conditional Privacy Preservation in VANETs

Certificateless aggregate signature reduces the trust in key generation center and eases the inconvenience of certificate management at a low cost of communication and computation. Because of these merits, a lot of new certificateless aggregate signature schemes have been proposed to provide enough security and privacy in vehicular ad hoc networks (VANETs). However, many of these schemes are insecure against various attacks. In this article, we analyze the security of an efficient certificateless aggregate signature with conditional privacy preservation in Internet of vehicles. The results of the analysis show that it is insecure against forgery attack. In order to overcome the security vulnerability, we put forth an improved scheme. Then, the formal and informal security analysis of our improved scheme both are provided, which show that the improved scheme meets the expected security requirements and is secure against several known attacks in VANETs. Finally, performance evaluation shows that our improved scheme is feasible for the VANETs in terms of computation and communication overhead.

Improved Certificateless Aggregate Signature Scheme Against Collusion Attacks for VANETs

Vehicle ad-hoc networks (VANETs) can offer numerous benefits, but also face many privacy and security issues. There exist the certificate management burden and key escrow issue in traditional public key infrastructure (PKI)-based and identity (ID)-based privacy-preserving authentication schemes, respectively. In addition, the security of some existing cryptographic schemes depends on strong assumptions about the ideal tamper-proof devices. To address these issues, a certificateless aggregate signature (CLAS) scheme for VANETs has been proposed, which was claimed provably unforgeable. However, we found that this scheme cannot resist collusion attacks, which means the equivalent validity of the aggregate signature would be broken. Therefore, this article proposes an improved CLAS scheme against collusion attacks for VANETs (CA-CLAS). Security and performance analyses show that the proposed CA-CLAS scheme not only offers privacy and security guarantees for VANETs, but also improves efficiency compared to existing authentication schemes.

A Novel Construction Of Certificateless Aggregate Signature Scheme For Healthcare Wireless Medical Sensor Networks

Abstract To ensure privacy and security of healthcare wireless medical sensor networks (HWMSNs), several concrete constructions of efficient certificateless aggregate signature (CLAS) scheme without bilinear pairing were proposed in the last few years. However, many previous constructions of CLAS scheme were found to be impractical, which either fail to meet the claimed security or contain design flaws. For example, in some of the previous proposals, any adversary can forge a valid signature on any new message. In this paper, we first demonstrate some security issues and design flaws in the previous proposals of CLAS scheme. As follows, to further address the above deficiencies, a new construction of CLAS scheme with improved security is presented, and the formal security proof is given using Forking Lemma in the random oracle model, assuming that the discrete logarithm problem is hard. Compared with the previous CLAS schemes, our construction has similar computational costs, and it provides better security guarantees. Therefore, compared with the existing solutions, our proposal with strong security and high computational efficiency is more suitable for use in HWMSNs.

An improved pairing-free certificateless aggregate signature scheme for healthcare wireless medical sensor networks.

In healthcare wireless medical sensor networks (HWMSNs), the medical sensor nodes are employed to collect medical data which is transmitted to doctors for diagnosis and treatment. In HWMSNs, medical data is vulnerable to various attacks through public channels. In addition, leakage of patients’ information happens frequently. Hence, secure communication and privacy preservation are major concerns in HWMSNs. To solve the above issues, Zhan et al. put forward a pairing-free certificateless aggregate signature (PF-CLAS) scheme. However, according to our cryptanalysis, the malicious medical sensor node (MSNi) can generate the forged signature by replacing the public key in the PF-CLAS scheme. Hence, to address this security flaw, we design the improved PF-CLAS scheme that can achieve unforgeability, anonymity, and traceability. Since we have changed the construction of the partial private key, the improved PF-CLAS scheme can resist Type I and Type II attacks under the Elliptic Curve Discrete Logarithm assumption. In terms of the performance evaluation, the proposed scheme outperforms related CLAS schemes, which is more suitable for HWMSNs environments.