Aggregate Signature Scheme Research Articles

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.

Lattice‐based batch authentication scheme with dynamic identity revocation in VANET

Aggregate signatures allow someone to aggregate multiple signatures into one signature, which is suitable for resource-constrained and computationally inefficient environments. Identify-based aggregate signature can solve the storage problem of public key certificates while achieving efficient signature verification. However, in most of the identity-based aggregate signature schemes, the user identity revocation process is time-consuming and cannot resist quantum attacks. To solve above problems, this paper proposes a lattice-based aggregate signature scheme with dynamic identity revocation by combining lattice-based cryptography and an aggregate signature scheme. The security of the proposed lattice-based aggregate signature scheme with dynamic identity revocation has been proved in the random oracle model. In addition, the verification efficiency of the aggregate signature has been improved compared with multiple different signatures. Much of the data transfer in Vehicular Ad Hoc Network (VANET) is carried out wirelessly, which makes VANET vulnerable to identity spoofing attacks. Identity authentication technology can prevent attackers from impersonating legitimate users, thus ensuring the security of VANET. Based on the proposed lattice-based aggregate signature scheme with dynamic identity revocation, this paper proposes a lattice-based batch authentication scheme with dynamic identity revocation in VANET. Through the proposed batch authentication scheme, we can effectively resist the impersonation attack of VANET in the quantum computer environment, and the efficiency of authentication is improved.

Secure aggregate signature scheme for smart city applications

With the recent advances in technology, smart cities are rapidly earning momentum. To provide better lives, smart cities should host several applications to increase the efficiency and accessibility of services. Since these services involve the conveyance of significant data among the smart cities’ cloud and the dwellers over the Internet, security and privacy are critical. This paper proposes an authentication protocol with a full aggregation signature to secure the smart city applications. A certificate-less aggregate signature (CLAS) is used for smart city real applications such as secure routing and database outsourcing. The proposed CLAS achieves message authentication, user anonymity, constant signature size, unlinkability, and is resistant to replay attacks. Also, we have proved that the proposed scheme is resistant to all malicious adversaries. Finally, the performance evaluation results show that the proposed CLAS performs better than existing relevant schemes.

Provably Secure Linearly Homomorphic Aggregate Signature Scheme for Electronic Healthcare System

In recent years, deploying Internet of Things (IoT) in electronic healthcare systems (EHS) has made great progress in healthcare detection. It is extremely important to reduce the cost of communication and ensure the authenticity and integrity of data. A linearly homomorphic signature scheme can solve the above problems. However, when the scale of EHS is too large, the transmission, storage and verification of signatures need a high cost. An aggregate signature can combine many signatures generated by many different users into a short one. Therefore, only one aggregate signature needs to be processed during verification, transmission and storage. Combining the advantages of aggregate signature and linearly homomorphic signature, this paper proposes an aggregate signature scheme based on a linearly homomorphic signature for EHS, which has both linear homomorphism and aggregation, and realizes double data compression. Moreover, our scheme can resist a potential real attack, named a coalition attack. The security of this scheme is rigorously demonstrated based on the computational Diffie–Hellman assumption in the random oracle model.

Certificate-Based Anonymous Authentication With Efficient Aggregation for Wireless Medical Sensor Networks

Wireless medical sensor networks (WMSNs) have aroused widespread attention in recent years with the development of Internet of Things (IoT) technology. WMSNs offer many new opportunities for healthcare professionals to monitor patients and patient self-monitoring. To overcome the resource (such as memory and power) limitations of sensors and attain data security of patients’ private medical information, researchers have designed plenty of work for securing WMSNs. For years, certificate-based aggregate signature (CBAS) schemes have been put forward for WMSNs to prevent patients’ sensitive medical data from being tampered with and damaged. In this work, we analyze the security flaws of a very recent CBAS scheme proposed by Verma <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">et al.</i> (2021) by presenting two types of security attacks. We later propose a CBAS scheme with user anonymity protection for WMSNs and prove its security based on the standard cryptographic assumption. The performance comparison results from theory and experiment illustrate the practicality of our design.

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.

A certificateless aggregate signature scheme for security and privacy protection in VANET

In the vehicular ad hoc network, moving vehicles can keep communicating with each other by entering or leaving the network at any time to establish a new connection. However, since many users transmit a substantial number of messages, it may cause reception delays and affect the entire system. A certificateless aggregate signature scheme can provide a signature compression that keeps the verification cost low. Therefore, it is beneficial for environments constrained by time, bandwidth, and storage, such as vehicular ad hoc network. In recent years, several certificateless aggregate signature schemes have been proposed. Unfortunately, some of them still have some security and privacy issues under specific existing attacks. This article offers an authentication scheme that can improve security, privacy, and efficiency. First, we apply the certificateless aggregate signature method to prevent the onboard unit devices from leaking sensitive information when sending messages. The scheme is proven to be secure against the Type-1 [Formula: see text] and Type-2 [Formula: see text] adversaries in the random oracle model under the computational Diffie–Hellman problem assumption. Then, the performance evaluation demonstrates that our proposed scheme is more suitable for deployment in vehicular ad hoc network environments.

CLASRM: A Lightweight and Secure Certificateless Aggregate Signature Scheme with Revocation Mechanism for 5G-Enabled Vehicular Networks

The rapid deployment of 5G technology has further strengthened the large-scale interconnection between sensing devices and systems and promoted the rapid development of smart cities and intelligent transportation systems. 5G-enabled vehicular networks take advantage of cellular vehicle-to-everything (C-V2X) technology to achieve the connection between moving vehicles, between vehicles and infrastructure, and between vehicles and the cloud, which can reduce the possibility of traffic jams and accidents, improve transportation efficiency, and realize automatic driving. Besides, 5G-enabled vehicular networks also provide infotainment services and industry application services. High-strength data transmission, however, will bring a serious burden of resource overhead, and there are hidden dangers of security and privacy in the communication process of vehicular networks. Some current vehicular network authentication schemes adopt public key infrastructure-based (PKI-based) and identity-based authentication methods to achieve conditional privacy preservation. Still, these schemes are too expensive and cannot address the problems of costly certificate management or risky key escrow. Some schemes use computationally complex bilinear pairing operations that result in low efficiency and do not consider the revocation of malicious nodes so that they cannot effectively prevent further malicious attacks. This paper proposes a lightweight certificateless aggregate signature (CLAS) scheme with a revocation mechanism suitable for 5G-enabled vehicular networks in response to the above problems. Our proposed scheme uses aggregation signature technology to aggregate multiple signatures into a single short signature, thus reducing communication overhead and storage overhead of road side units (RSUs). Furthermore, our proposed scheme utilizes the elliptic curve cryptography (ECC) to reduce verification time and computational overhead. Moreover, in order to prevent malicious users from sending invalid signatures to attack, our proposed scheme uses binary search to identify invalid signatures and introduces a cuckoo filter to revoke malicious users to prevent reattack. Finally, formal proof and experimental analysis show that our proposed scheme has greater advantages with respect to security and efficiency compared with the previous schemes.

ECLAS: An Efficient Pairing-Free Certificateless Aggregate Signature for Secure VANET Communication

Vehicular ad hoc networks (VANETs) have become an important part of the intelligent transportation system that aims to promote communication among vehicles to ensure vehicular safety and improve the driving experience. In VANETs, signed messages need to be authenticated by roadside units in a very short time. Certificateless aggregate signature (CLAS) scheme has been considered as one of the promising solutions to solve the problem of limited network bandwidth and computing power in VANETs environment. In this article, we propose an efficient pairing-free CLAS, named eCLAS, which is suitable for communication between vehicle to infrastructure. The aggregated signature allows individual signature on different messages from different vehicles to be aggregated into one short signature. In the random oracle model, the security of the scheme is proved by the adaptive selection message attack and the difficulty of computation of discrete logarithm problem on the elliptic curve. Additionally, the security analysis shows that the proposed scheme can meet security requirements in VANETs. Compared with existing schemes, the result demonstrates that our scheme has obvious advantages in signature verification, thereby granting it better applicability.

The Secure Lattice-Based Data Aggregation Scheme in Residential Networks for Smart Grid

With the rapid development of computer networks, the network architecture has been more and more complex and diverse. Smart grid is a kind of wireless sensor network consuming energy in smart city. Smart grid communications have developed rapidly in recent years, while the privacy, integrity, and confidentiality of user data have been the main security issues. However, lattice-based homomorphic cryptography can resist quantum attacks and effectively provide the security of the scheme. In this article, we proposed an aggregate signature scheme based on new Batch RSA. After that, a data aggregation scheme is proposed based on this aggregate signature scheme and the qualified homomorphic cryptosystem. Compared to the previous schemes, our scheme is more secure because we implement seven properties, such as post quantum, privacy, and so on. Compared to the representative scheme proposed by Abdallah <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">et al.</i> , our scheme has lower computation and communication overhead. In addition, the cryptographic algorithms involved in our scheme are lightweight. The network model in our scheme is suitable for large intelligent communities. So, our scheme is very suitable for the residential area network.

An Efficient Certificate-Based Aggregate Signature Scheme for Internet of Drones

Internet of drones (IoD) is a network of small drones that leverages IoT infrastructure to deliver real-time data communication services to users. On the one hand, IoD is an excellent choice for a number of military and civilian applications owing to key characteristics like agility, low cost, and ease of deployment; on the other hand, small drones are rarely designed with security and privacy concerns in mind. Intruders can exploit this vulnerability to compromise the security and privacy of IoD networks and harm the information exchange operation. An aggregate signature scheme is the best solution for resolving security and privacy concerns since multiple drones are connected in IoD networks to gather data from a certain zone. However, most aggregate signature schemes proposed in the past for this purpose are either identity-based or relied on certificateless cryptographic methods. Using these methods, a central authority known as a trusted authority (TA) is responsible for generating and distributing secret keys of every user. However, the key escrow problem is formulated as knowing the secret key generated by the TA. These methods are hampered by key distribution issues, which restrict their applicability in a variety of situations. To address these concerns, this paper presents a certificate-based aggregate signature (CBS-AS) scheme based on hyperelliptic curve cryptography (HECC). The proposed scheme has been shown to be both efficient in terms of computation cost and unforgeable while testing its toughness through formal security analysis.

BlockREV: Blockchain-Enabled Multi-Controller Rule Enforcement Verification in SDN

Compared with the classical structure with only one controller in software-defined networking (SDN), multi-controller topology structure in SDN provides a new type of cross-domain forwarding network architecture with multiple centralized controllers and distributed forwarding devices. However, when the network includes multiple domains, lack of trust among the controllers remains a challenge how to verify the correctness of cross-domain forwarding behaviors in different domains. In this paper, we propose a novel secure multi-controller rule enforcement verification (BlockREV) mechanism in SDN to guarantee the correctness of cross-domain forwarding. We first adopt blockchain technology to provide the immutability and privacy protection for forwarding behaviors. Furthermore, we present an address-based aggregate signature scheme with appropriate cryptographic primitives, which is provably secure in the random oracle model. Moreover, we design a verification algorithm based on hash values of forwarding paths to check the consistency of forwarding order. Finally, experimental results demonstrate that the proposed BlockREV mechanism is effective and suitable for multi-controller scenarios in SDN.

Design Principles of Secure Certificateless Signature and Aggregate Signature Schemes for IoT Environments

Certificateless cryptography resolves the certificate management problem of public-key cryptography and the key-escrow problem of identity-based cryptography. An aggregate signature scheme which allows to aggregate <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">k</i> distinct signatures on <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">k</i> distinct messages of <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">k</i> distinct signers into a single signature reduces communication overhead and computational cost. Due to the suitability of certificateless signature (CLS) and certificateless aggregate signature (CLAS) schemes for IoT environments, similar CLS and CLAS schemes have been proposed for a long time and, despite their security proofs, they have been attacked and modified to prevent the attacks. Even now, similar design methods and similar attacks on the schemes are being repeated. In order to prevent the similar attacks on the schemes, it is necessary to analyze their causes and vulnerabilities. In this paper, we first show that recently proposed five CLS and CLAS schemes are insecure against universal forgery attacks, type I attacks, type II attacks or malicious-but-passive-KGC attacks. We discuss their security flaws, causes and countermeasures. We then present design principles to prevent various algebraic attacks including our attacks. The design principles will help in the construction of secure CLS and CLAS schemes against the previous attacks and potential attacks.

Code-based Sequential Aggregate Signature Scheme

This paper proposes the first code-based quantum immune sequential aggregate signature (SAS) scheme and proves the security of the proposed scheme in the random oracle model. Aggregate signature (AS) schemes and sequential aggregate signature schemes allow a group of potential signers to sign different messages respectively, and all the signatures of those users on those messages can be aggregated into a single signature such that the size of the aggregate signature is much smaller than the total size of all individual signatures. Because of the aggregation of many signatures into a single short signature, AS and SAS schemes can reduce bandwidth and save storage; moreover, when a SAS is verified, not only the valid but also the order in which each signer signed can be verified. AS and SAS schemes can be applied to traffic control, banking transaction and military applications. Most of the existing AS and SAS schemes are based either on pairing or Rivest–Shamir–Adleman (RSA), and hence, can be broken by Shor’s quantum algorithm for Integer Factoring Problem (IFP) and Discrete Logarithm Problem (DLP). There are no quantum algorithms to solve syndrome decoding problems. Hence, code-based cryptography is seen as one of the promising candidates for post-quantum cryptography. This paper shows how to construct quantum immune sequential aggregate signatures based on coding theory. Specifically, we construct our scheme with the first code based signature scheme proposed by Courtois, Finiasz and Sendrier (CFS). Compared to the CFS signature scheme without aggregation, the proposed sequential aggregate signature scheme can save about 90% storage when the number of signers is asymptotically large.

Improving Bitcoin’s Post-Quantum Transaction Efficiency With a Novel Lattice-Based Aggregate Signature Scheme Based on CRYSTALS-Dilithium and a STARK Protocol

This paper proposes a novel lattice-based aggregate signature (LAS) scheme that bring post-quantum security to the Bitcoin system without sacrificing its transaction efficiency. Bitcoin currently employs Elliptic Curve Digital Signature Algorithm (ECDSA), which is insecure against the emerging quantum technology, so post-quantum signature schemes like the proposed LAS will become necessary in the near future. However, most of the post-quantum signatures schemes have large signature sizes which decrease Bitcoin’s efficiency while our proposed scheme does not have this negative side effect. Our LAS scheme is based on CRYSTALS-Dilithium and a zero-knowledge Scalable Transparent Arguments of Knowledge (STARK) protocol. CRYSTALS-Dilithium is the most prominent algorithm chosen by the National Institute of Standards and Technology (NIST), yet it still has an adverse limitation: it would cause Bitcoin’s transaction efficiency to fall by 17 times due to its relatively large signature size. On the other hand, the proposed LAS scheme takes full advantage of signature aggregation using the STARK protocol and Dilithium’s easy and fast implementation, thus generating signatures with post-quantum security and small signature sizes which are critical to transaction efficiency. Our proofs convey the correctness, compactness, and post-quantum security of our construction in the quantum random oracle model, and our implementation conveyed that the proposed scheme would only decrease Bitcoin’s transaction efficiency by 3 times, a significant improvement from using Dilithium and other lattice-based aggregate signature schemes. Our proposed scheme has many advantages over the existing schemes and may become very valuable to Bitcoin.

A Verifiable Credentials System with Privacy-Preserving Based on Blockchain

Decentralized identity authentication is generally based on blockchain, with the protection of user privacy as the core appeal. But traditional decentralized credential system requires users to show all the information of the entire credential to the verifier, resulting in unnecessary overexposure of personal information. From the perspective of user privacy, this paper proposed a verifiable credential scheme with selective disclosure based on BLS (Bohen- Lynn-Shacham) aggregate signature. Instead of signing the credentials, we sign the claims in the credentials. When the user needs to present the credential to verifier, the user can select a part of but not all claims to be presented. To reduce the number of signatures of claims after selective disclosure, BLS aggregate signature is achieved to aggregate signatures of claims into one signature. In addition, our scheme also supports the aggregation of credentials from different users. As a result, verifier only needs to verify one signature in the credential to achieve the purpose of batch verification of credentials. We analyze the security of our aggregate signature scheme, which can effectively resist aggregate signature forgery attack and credential theft attack. The simulation results show that our selective disclosure scheme based on BLS aggregate signature is acceptable in terms of verification efficiency, and can reduce the storage cost and communication overhead. As a result, our scheme is suitable for blockchain, which is strict on bandwidth and storage overhead.

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

Vehicular ad hoc networks (VANETs) are the communication foundation for future intelligent transportation systems and guarantee safe driving of intelligent networked vehicles. Moreover, VANETs face a series of security challenges related to the protection of vehicle privacy, authenticity of transmitted information, and bandwidth limitations. To resolve these contradictions, many certificateless aggregate signature (CLAS) schemes have been proposed. However, the majority of them can neither resist malicious-but-passive key generation center attacks, replay attacks, and link attacks, nor track the actual identities of malicious vehicles. Meanwhile, the security of previous CLAS schemes in VANETs is only formally provided in the random oracle model (ROM), which might be insecure in actual implementation. In addition, most CLAS schemes still have problems of large verification delays and high communication overhead. To address the above-mentioned problems, a new conditional privacy-preserving CLAS scheme in VANETs is proposed, which adopts full aggregation technology to reduce computation and bandwidth resources. According to the formal security proofs under the computational Diffie-Hellman problem (CDHP) given in the standard model (SM), the security level of this scheme is higher than that of other CLAS schemes under ROM in practical applications. Additionally, the use of pseudonym mechanism realizes conditional privacy protection in VANETs. The performance analysis shows that this scheme has a higher efficiency in terms of computation and communication overhead compared with several previous CLAS schemes.

Atomic cross-chain settlement model for central banks digital currency

Current securities settlement systems employ various strategies to manage risks in settlement effectively. However, exchanging and verifying information between the market participants and intermediaries is time consuming.In addition, the back office and coordination costs are very high. To address such challenges, blockchain technology has attracted the attention of researchers due to its potential as a new settlement system. In this study, we propose a blockchain-based settlement system using cross-chain atomic swaps that can be implemented for the central banks digital currency (CBDC). The proposed model adds an administrator ledger to the system to remove settlement failure and improve efficiency in market management. Along with our settlement system, we also propose a new lattice-based sequential aggregate signature scheme generally known for its advantage on resisting future quantum attacks. Proof-of-concept experiments with the proposed system were conducted to analyze the effect of numerous variables in the blockchain ecosystem on the settlement system.

Extraction Security of Sequential Aggregate Signatures

Aggregate signature schemes enable anyone to compress many signatures into one. Besides the unforgeability of aggregate signature, another property called aggregate extraction sometimes is useful. In sequential aggregate signature schemes, the aggregate signature is computed incrementally by the signers. We introduce extraction security in the sequential context which can be seen as an analogy of aggregate extraction introduced by Boneh et al. in CRYPTO 2003. In addition to the practical meaning, it also has benefits in the construction of hierarchical identity-based signatures as we will point out. We study several well known aggregate signature schemes and prove some of them satisfy extraction security.

Achieving Pairing-Free Aggregate Signatures using Pre-Communication between Signers

Most aggregate signature schemes are relying on pairings, but high computational and storage costs of pairings limit the feasibility of those schemes in practice. Zhao proposed the first pairing-free aggregate signature scheme (AsiaCCS 2019). However, the security of Zhao's scheme is based on the hardness of a newly introduced non-standard computational problem. The recent impossibility results of Drijvers et al. (IEEE S&P 2019) on two-round pairing-free multi-signature schemes whose security based on the standard discrete logarithm (DL) problem have strengthened the view that constructing a pairing-free aggregate signature scheme which is proven secure based on standard problems such as DL problem is indeed a challenging open problem. In this paper, we offer a novel solution to this open problem. We introduce a new paradigm of aggregate signatures, i.e., aggregate signatures with an additional pre-communication stage. In the pre-communication stage, each signer interacts with the aggregator to agree on a specific random value before deciding messages to be signed. We also discover that the impossibility results of Drijvers et al. take effect if the adversary can decide the whole randomness part of any individual signature. Based on the new paradigm and our discovery of the applicability of the impossibility result, we propose a pairing-free aggregate signature scheme such that any individual signature includes a random nonce which can be freely generated by the signer. We prove the security of our scheme based on the hardness of the standard DL problem. As a trade-off, in contrast to the plain public-key model, which Zhao's scheme uses, we employ a more restricted key setup model, i.e., the knowledge of secret-key model.