Design and Security Analysis of Certificateless Aggregate Signature Scheme

Cryptanalysis and improvement of a certificateless aggregate signature scheme

An aggregate signature (AS) scheme combines multiple signatures which is generated by many different users into a single one. This feature is very beneficial for diminishing storage cost, bandwidth and verification cost. Many previous attempts have been made for designing AS schemes, while the former security models have not clearly addressed coalition attacks, and most of the existing AS schemes cannot resist these kinds of attacks. In this study, the authors provide a modified security model of certificateless AS (CLAS) schemes and then give a new CLAS scheme. The security of their present scheme can be rigorously proved based on the computational Diffie-Hellman assumption in the random oracle model. Furthermore, their scheme can resist such coalition attacks, i.e. an AS in their scheme is valid iff all single signatures used to generate the AS are valid.

Vehicular Ad-Hoc Network (VANET) is an open environment. In VANET, it needs protect some privacy information of the vehicle, such as the real identity of the vehicle, the number of the vehicle. Certificateless aggregate signature (CLAS) scheme can reduce the calculation cost and communication cost due to the aggregation property, which is important part of cryptography. In this paper, we present two CLAS schemes proposed recently and also give a security analysis on the two CLAS schemes. By security analysis on the both CLAS schemes, it finds that the two CLAS schemes can be forged by the malicious enemy by replacing the public key of the user but without knowing the master key of key generation center. At the same time, we also show that second CLAS scheme does not satisfy the tractability property. In other words, the malicious vehicle cannot be traced after it makes some malicious signatures. We also present an improved CLAS schemes based on the original CLAS scheme respectively. By some security analysis and efficiency analysis, it can find that the improved CLAS schemes both not only can overcome the security problem but also are still efficient.

Cryptographic algorithm plays an important role in the teaching of network security course. Certificateless aggregate signature (CLAS) scheme is an important cryptographic algorithm in cryptography. Many CLAS schemes have been proposed with some property, such as designated verifier property. Designated verifier property makes it possible for a specific person to verify the signature which can be applied in many scenes, such as medicine and biology system and et al. In this paper, we analyze a CLAS scheme with designated verifier property proposed in 2020 which satisfies designated verifiability property, unforgeability property and non-transitivity property. However, we point out that the CLAS scheme does not satisfy the unforgeability as they claimed. We present two improved methods to overcome these existed security drawbacks. By analyzing the security of a CLAS scheme and proposing some improved methods, it can let students know how to better design a secure cryptographic algorithm in process of network security course.

Certificateless aggregate signature can provide an efficient way to verify a large amount of signatures from different users. This feature makes it very useful in the environments with low bandwidth communication, low storage, and low computability. Recently, Chen et al. proposed a new certificateless aggregate signature scheme. They claim that their scheme is provably secure under the computational Diffie–Hellman problem. Unfortunately, this paper shows that Chen et al.'s scheme is insecure, it cannot resist Type I and Type II adversaries, and the corresponding attacks are given. Furthermore, we also show their scheme exists a more powerful attack, namely, anyone can forge a certificateless signature on an arbitrary message in this attack. Finally, we discuss the reason to produce such attacks and give the corresponding suggestions to resist such attacks. Copyright © 2015 John Wiley & Sons, Ltd.

A new attack against a novel certificateless aggregate signature scheme with constant pairing computations is presented. To enhance security, a new certificateless signature scheme is proposed first. Then a new certificateless aggregate signature scheme with constant pairing computations based on the new certificateless signature scheme is presented. Security analysis shows that the proposed certificateless aggregate signature scheme is provably secured in the random oracle.

CL-ASS: An efficient and low-cost certificateless aggregate signature scheme for wireless sensor networks

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.

In this paper, we propose two certificateless aggregate signature schemes, which are the first aggregate signature schemes in the CL-PKC. The first scheme CAS -1 reduces the costs of communication and signer-side computation but loses on storage, while CAS - 2 minimizes the storage but sacrifices the communication. We can choose one of the above schemes by the consideration of the implementation requirement. Our schemes do not need the public key certificate anymore and achieve the trust level 3, the same level with traditional PKI. Both of the schemes are proven secure in the random oracle model(ROM) by assuming the intractability of the computational Diffie-Hellman(CDH) problem over groups with bilinear maps.

Due to the limited energy of underwater wireless sensor network (UwWSN) and the need to protect node location privacy, aggregate signature (AGGS) scheme which can batch verification signature is proposed to meet these requirements. Due to moving at high speed and the limited bandwidth of communication in vehicular ad hoc network (VaNET), certificateless aggregate signature (CTLAS) with the private key being generated by the signer itself and PKG (Private Key Generator) is proposed to solve the above problems. Recently, Yang et al. proposes a CTLAS scheme which can be applied into VaNET and Hua proposes an AGGS scheme which can be applied into UwWSN. This paper shows that Yang et al.'s CTLAS scheme and Hua's AGGS scheme both are not secure. In Yang et al.'s CTLAS scheme, an attacker can forge a signature assume that the attacker cannot know the masker key of PKG but the attacker can replace the public key of the signer. In Hua's AGGS scheme, a malicious node can forge a signature for any nodes after the malicious node obtains a temporary key. As an improvement, this paper also proposes an improved method for Yang et al.'s scheme and Hua's scheme respectively.

An aggregate signature refers to a signature, by which n signatures σ1,...,σn corresponding to n messages m1,...,mn and n users u1,...,un can be transformed into a single short signature . Besides, anyone can be convinced by the single short signature that the n messages m1,...,mn were definitely signed by the n users u1,...,un correspondingly. The concept of certificateless cryptography is proposed, so as to settle the key escrow problem in ID‐based cryptography and eliminate the demand for certificates in certified cryptography. A certificateless signature scheme was proposed by Chen et al. in 2014, which was extended into a certificateless aggregate signature scheme. In this paper, two attacks are firstly provided, so as to indicate that the certificateless signature scheme is insecure against a Type I adversary and a Type II adversary. And then, it is demonstrated that the certificateless aggregate signature scheme is not able to achieve the security levels they claimed due to the weaknesses of the certificateless signature scheme. Copyright © 2016 John Wiley & Sons, Ltd.

With the rapid miniaturization in sensor technology, ruddervator, arduino, and multi-rotor system, drone technology catches much attention of the researchers. It can be controlled remotely by a seated operator sitting to a powerful intelligence computer system (PICS) or an airborne control and command platform (AC2P). The two types of drones (reconnaissance and attacking) can communicate with each other and with the PICS or AC2P through wireless network channels referred to as Flying Ad Hoc Network or Unmanned Aerial Vehicular Network (FANET or UAVN). When the line of sight is broken, communication is mainly carried out through satellite using GPS (Global Positioning System) signals. Both GPS and UAVN/FANET use open network channels for data broadcasting, exposed to several threats, and its security is challenging for the researchers. Monitoring data transmission traffic, espionage, troop movement, border surveillance, searching and warfare battlefield phenomenon, etc., can auspiciously be achieved by developing a robust authentication scheme for IoD deployment military drone. Therefore, this research illustrates the designing of two separate protocols based on aggregate signature, identity, pairing cryptography, and Computational Diffie-Hellman Problem (CDHP) to guarantee data integrity, authorization, and confidentiality among drones and AC2P/PICS. The outdated data transmission flaw has also been tackled, which is frequently noted in prior protocols. The security of these protocols will formally be verified using a random oracle model (ROM), a real-or-random (ROR) model, and informally using pragmatic illustration and mathematical lemmas. Nonetheless, the performance analysis section will be executed using the algorithmic big-O notation. The results show that these protocols are verifiably protected in the Random Oracle Model (ROM) and Real-Or-Random (ROR) model using the CDHP.

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.

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

Digital signature with proxy delegation, which is a secure ownership enforcement tool, allows an original signer to delegate signature rights to a third party called proxy, so that the proxy can sign messages on behalf of the original signer. In today’s modern society, many applications use this mechanism. Several types of delegations are quite prevalent and the delegation of signing authority is one of them. In a traditional digital signature scheme, signer transmits signature along with message for verification, which leads to additional communication, computation cost and requires extra bandwidth. To resolve these issues, in this paper, we present an efficient ID-based proxy signature scheme with message recovery using bilinear pairings. Because of the message recovery feature, the proxy signer need not send the message to the verifier, so that the proposed scheme reduces the bandwidth requirement and communication cost. Our proposed scheme is proven secure against existential forgery under adaptively chosen message and identity attacks in the random oracle model (ROM) with the assumption that the Computational Diffie-Hellman Problem (CDHP) is intractable. We compare our scheme with related schemes. The efficiency analysis shows that the scheme is computationally efficient. Thus the proposed ID-based proxy signature scheme is secure and efficient both in terms of computation and communication costs than the related existing schemes.