Random Oracle Research Articles

A heterogeneous signcryption scheme with Cryptographic Reverse Firewalls for IoT and its application

The Snowden leaks exposed the truth that skilled attackers can access users’ devices and steal their private information. Although public key encryption is widely used and theoretically secure, it has hidden vulnerabilities when implemented in practice. This is especially problematic when employing communication channels among heterogeneous protocols within the Internet of Things (IoT), it becomes apparent that these channels lack adequate protection to address the diverse nature of IoT systems. This work proposes a novel Heterogeneous Online/Offline Signcryption with Cryptographic Reverse Firewalls (HOOS-CRF). The scheme enables a secure communication channel between the sender in an Identity-based cryptosystem (IBC) and the receiver in the Public Key Infrastructure (PKI) cryptosystem with CRF deployed. To reduce computational costs, we split the signcryption algorithm into two stages: online and offline. Most resource-intensive operations are performed during the offline stage, which operates without any knowledge of the message being processed. The HOOS-CRF scheme provides confidentiality, authentication, and defense against insider security attacks. Meanwhile, we prove the security of the HOOS-CRF using the random oracle model and demonstrate its high efficiency and practicality through experiments. Lastly, the scheme’s relevance to IoT-driven healthcare applications is demonstrated.

Efficient and quantum‐secure authenticated key exchange scheme for mobile satellite communication networks

SummaryThe mobile satellite communication (MSC) system is a vital communication method in which mobile users and network control centers connect via satellites. Since the satellite's communication is wireless, communication security is a critical factor to ensure accountable communication. Key exchange and authentication (KEA) mechanism is widely used to achieve data security for data transmitted in an insecure or open channel. Different authentication systems are suggested in the last many years to establish safe communication, whereas most existing security protocols are based on factorization or discrete logarithm. However, these systems are no longer reliable by Shor's algorithm as any discrete logarithm and factorization can be resolved in polynomial time on quantum computers. Thus, developing a quantum secure KEA protocol for MSC systems is necessary. In this direction, recently a ring learning with an error‐based KEA technique is proposed to ensure a quantum‐safe environment. This scheme is quantum‐safe and satisfies desirable security attributes but has low efficiency in computation and communication. Moreover, establishing a secure session requires six communications among involved entities. As a result, replay attack detection at an early stage is not possible for the central authority (server), which could delay the server response, and the adversary gets the advantage of drawing a denial of service scenario for authorized entities. We propose a lattice‐based KEA protocol for the MSC system to improve computation, communication efficiency, and early‐stage replay attack detection. The security analysis of the proposed scheme is presented in the random oracle model. Calculation of performance is also presented to observe advantages in computation and communication overhead.

Cryptanalysis with improvement on lattice‐based authenticated key exchange protocol for mobile satellite communication networks

SummaryThe mobile satellite communication (MSC) system represents a crucial means of communication, facilitating connections between mobile users and network control centres through satellites. Given the wireless nature of satellite communication, ensuring communication security is paramount for maintaining accountability. Key exchange and authentication (KEA) mechanisms are commonly employed to secure data transmitted over insecure or open channels. Developing a lattice‐based KEA protocol for MSC systems is imperative to achieve both quantum security and efficient communication. In this direction, Yadav et al. devised ring learning with an error‐based KEA technique to ensure a quantum‐safe environment. Their scheme is quantum‐safe and satisfies desirable security attributes but has low efficiency in computation. Moreover, we have identified that their scheme is susceptible to denial of service attack and session key established at user and NCC ends is different. To overcome the flaws of Yadav et al., we propose a lattice‐based KEA protocol for the MSC system to improve computation efficiency, and get resistance against key mismatch attack. The security analysis of the proposed scheme is presented in the random oracle model. Comparative study is also presented to observe advantages in computation efficiency.

A new three-factor authentication scheme using Chebyshev chaotic map for peer-to-peer Industrial Internet of Things

The Industrial Internet of Things (IIoT) is an emerging technology for smart manufacturing and productivity improvement. Due to the increasing complexity of manufacturing, devices with smart industrial sensors from several domains work together on the same job, raising serious security and privacy concerns about peer-to-peer (P2P) communication. Specifically, P2P secure communication should be focused on when it comes to high efficiency and security of information exchange between two industrial sensors. However, none of the existing schemes can resist physical attacks towards industrial sensors. To resolve the problem, we propose a new three-factor authentication and key agreement scheme named NTFAK for P2P IIoT communication using Physical Unclonable Functions (PUF) and Chebyshev chaotic mapping, where PUF is used to replace the smart card factor in the traditional schemes. The unclonable property of PUF and its ability to securely identify a device by challenge-response can provide safety to physical attacks. Besides, the use of the Chebyshev chaotic map also can provide high computational efficiency while ensuring better security. The proposed scheme enables secure communication between any two industrial sensors, which can resist physical attacks and offer a smaller key size, faster computation, and higher efficiency for IIoT. The security of our scheme is formally proved by the random oracle model, and security properties are discussed to show our scheme resists various attacks. Moreover, experiments were implemented to prove the efficiency of our scheme. Specifically, the results show that NTFAK can improve the computation and communication overheads by 36.6% and 17.5% at least, compared to existing schemes, while also ensure a minimum time reduction of 30.4% in delay time. In terms of security and functionality features, NTFAK satisfies the proposed 14 properties, outperforming existing solutions.

Enhancing online health consultations through fuzzy logic-integrated attribute-based encryption system

Online health consultations are becoming more popular as a result of technological improvements. Patients routinely look for information about medical disorders online, which could jeopardize the privacy of medical records and increase the workload of healthcare professionals. Nonetheless, academics continue to be extremely concerned about issues related to the quality characteristics that relate to the current architectural models, such as energy consumption, latency, resource utilization, scalability, and packet loss. This method, however, also results in a significant strain being placed on medical experts who must sort through vast amounts of medical records to extract certain information. This paper presents a novel ciphertext policy attribute-based encryption method coupled with fuzzy logic to overcome these issues. This solution uses a hybrid structure of IPFS and blockchain to store data and enables complex bidirectional access control. Before being added to IPFS, medical records are encrypted. To ensure data integrity, related IPFS hash indexes are then added to the blockchain. Utilizing attribute-based technology, users’ data is encrypted to give them fine-grained bidirectional access control. A thorough security analysis proves the system’s resilience, especially when faced with chosen plaintext assaults inside the random oracle model. Tests for this study were conducted using 10–50 attribute sets. This paper’s technique solely makes use of a hash operation. All things considered; the study demonstrates that the proposed design is more efficient than earlier schemes. Thus, from the comparison study above, it can be concluded that the system presented in this work is more efficient. Results from simulations provide additional support for the suggested methodology by highlighting the improved computing efficiency of users as compared to baseline conventional systems. This study demonstrates how technological advancement and healthcare requirements can coexist harmoniously, paving the way for secure and effective online medical consultations that are powered by fuzzy logic.

Attribute-based key management for patient-centric and trusted data access in blockchain-enabled IoMT

Internet of Medical Things (IoMT) provides real-time data collection and access services to medical entities by connecting their devices to Internet. However, within such a complex architecture, achieving patient-centric data access still presents trustworthiness challenges of transmission security and usage reliability. Ciphertext-policy attribute-based encryption (CP-ABE) and blockchain are both the promising primitives that support patients with secure access control over their data. Nevertheless, both have their unique key management issues. In this paper, we propose a novel patient-centric and trusted data access (PCT-DA) system in blockchain-enabled IoMT. Firstly, we develop an online/offline encryption and verifiable outsourced decryption CP-ABE scheme to relieve the computation pressure on patients and users. Secondly, we design a flexible attribute-based key management mechanism to overcome the security drawbacks of encryption and attribute keys, such as single point of failure, key escrow and privacy leakage. Finally, we build a trusted integrity audit contract to guarantee the incentive fairness between patients and users in access services. Moreover, theoretical analyses prove that the PCT-DA system not only achieves confidentiality, integrity, traceability and forward/backward security, but also guarantees static security under random oracles. Simulation experiments indicate that our proposal reduces the time cost by approximately 14.10 seconds over state-of-the-art and is more practical in blockchain-enabled IoMT system.

A quantum-secure certificateless aggregate signature protocol for vehicular ad hoc networks

Vehicular ad hoc networks (VANETs) have revolutionized communication between vehicles and infrastructure, notably enhancing traffic management and passenger safety. However, VANETs are vulnerable to security threats, especially regarding data authenticity. Aggregate signature is a powerful technique that reduces computational and communication burdens by aggregating multiple signatures from different signers into a single signature. Traditional aggregate signature schemes, based on large prime number decomposition and the discrete logarithm problem, cannot effectively resist quantum attacks. This paper introduces a novel quantum secure certificateless aggregate signature (QSCLAS) scheme designed to enhance data security and privacy in VANETs. Our proposed scheme employs the number theory research unit (NTRU) algorithm. As a lattice-based cryptographic algorithm, NTRU is renowned for its security against quantum computer attacks, making it an essential component of our quantum-secure solution. By eliminating the need for expensive bilinear pairing operations, our proposed scheme achieves high efficiency and practicality in resource-limited VANETs environments. The security analysis demonstrates our scheme's resilience against both Type-I and Type-II adversaries in the random oracle model under the small integer solution (SIS) problem on the NTRU lattice. Furthermore, compared with existing approaches, the results illustrate that our proposed scheme offers significant advantages in signature generation and verification cost, as well as lower transmission overhead than other lattice-based schemes, thereby making it highly suitable for VANETs environments.

Post‐quantum attack resilience blockchain‐assisted data authentication protocol for smart healthcare system

AbstractThe smart healthcare system (SHS), a significant medical domain underpinning the Internet of Things (IoT), which collects and analyzes health data from many sources to provide better medical treatment. The smart healthcare system is a combination of hardware and software used in the medical care field, providing remote diagnosis and treatment via a patient‐based health data‐sharing system. To increase security, a large variety of authenticated techniques have been developed over the past several decades, most of which are based on conventional number‐theoretic assumptions such as discrete logarithms and integer factorization problems. However, Shor's method is capable of solving number‐theory‐based problems. As a result, Shor's technique might be used to resolve challenging number theory problems on a quantum computer effectively. Therefore, this article presents blockchain‐based healthcare record solutions with lattice RLWE‐based key exchange protocol using a smart card. Blockchain applications may correctly detect errors, including those that are risky, in the medical industry. It can also improve the efficiency, security, and transparency of transferring medical data throughout the healthcare protocol. The formal security of this protocol is shown under the ROM (random oracle model), and the informal security is also given in this article against well‐known attacks. The presented protocol outperforms related earlier mechanisms in terms of communication and computational cost overheads, according to the performance study.

Provably Secure ECC-Based Anonymous Authentication and Key Agreement for IoT

With the rise of the Internet of Things (IoT), maintaining data confidentiality and protecting user privacy have become increasingly challenging. End devices in the IoT are often deployed in unattended environments and connected to open networks, making them vulnerable to physical tampering and other security attacks. Different authentication key agreement (AKA) schemes have been used in practice; several of them do not cover the necessary security features or are incompatible with resource-constrained end devices. Their security proofs have been performed under the Random-Oracle model. We present an AKA protocol for end devices and servers. The proposal leverages the ECC-based key exchange mechanism and one-way hash function-based message authentication method to achieve mutual authentication, user anonymity, and forward security. A formal security proof of the proposed scheme is performed under the standard model and the eCK model with the elliptic curve encryption computational assumptions, and formal verification is performed with ProVerif. According to the performance comparison, it is revealed that the proposed scheme offers user anonymity, perfect forward security, and mutual authentication, and resists typical attacks such as ephemeral secret leakage attacks, impersonation attacks, man-in-the-middle attacks, and key compromise impersonation attacks. Moreover, the proposed scheme has the lowest computational and communication overhead compared to existing schemes.

Simple Two-Message OT in the Explicit Isogeny Model

In this work we study algebraic and generic models for group actions, and extend them to the universal composability (UC) framework of Canetti (FOCS 2001). We revisit the constructions of Duman et al. (PKC 2023) integrating the type-safe model by Zhandry (Crypto 2022), adapted to the group action setting, and formally define an algebraic action model (AAM). This model restricts the power of the adversary in a similar fashion to the algebraic group model (AGM). By imposing algebraic behaviour to the adversary and environment of the UC framework, we construct the UC-AAM. Finally, we instantiate UC-AAM with isogeny-based assumptions, in particular the CSIDH action with twists, obtaining the explicit isogeny model, UC-EI; we observe that, under certain assumptions, this model is "closer" to standard UC than the UC-AGM, even though there still exists an important separation. We demonstrate the utility of our definitions by proving UC-EI security for the passive-secure oblivious transfer protocol described by Lai et al. (Eurocrypt 2021), hence providing the first concretely efficient two-message isogeny-based OT protocol in the random oracle model against malicious adversaries.

Attribute Based Signature Encryption Scheme Based on Cloud Computing in Medical Social Networks

The emergence of mobile medical social networks has provided great convenience for patients to communicate with each other about their medical conditions, promoting efficient and high-quality communication and exchange among patients. However, at the same time, it has also raised issues of confidentiality and privacy of patient data. In response to this issue, this article proposes a cloud-based attribute-based signature encryption scheme that can effectively protect the privacy of patient data. The patient encrypts their medical information and uploads it to the cloud server. When the data user wants to access the patient’s information, the cloud server helps the data user partially decrypt and verify the integrity of the data, which to some extent reduces the computational workload of the data user. Meanwhile, under the random oracle model, it has been proven that the scheme satisfies the unforgeability under selective message attacks, indistinguishability under selective cipher text attacks, and attribute privacy security. Theoretical analysis and numerical simulation experiments show that this scheme has higher efficiency than existing schemes in the signing and decryption stages.

A certificateless signcryption with proxy-encryption for securing agricultural data in the cloud

Precision agriculture (PA) involves collecting, processing, and analyzing datasets in agriculture for an informed decision. Due to the high data storage and application maintenance costs, farmers usually outsource their agricultural data obtained from PA to cloud service providers to leverage cloud services. Nonetheless, serious security concerns arise from using cloud services for farmers. For instance, an attacker can intercept agricultural data and run comprehensive statistical analyses to adjudicate farmers’ financial status, extort money, commit identity theft, etc. As a result, compelling data security schemes have become crucial for secure precision farming, where only legitimate users are required to access the agricultural data outsourced to the cloud. This article presents a certificateless signcryption scheme with proxy re-encryption (CLS-PRE) for secure access control in PA. An in-depth security analysis proves that the CLS-PRE scheme is secure in the Random Oracle Model. Detailed performance evaluation also shows that the scheme can reduce the time required to signcrypt and unsigncrypt messages and lower communication overhead.

Simple Three-Round Multiparty Schnorr Signing with Full Simulatability

In a multiparty signing protocol, also known as a threshold signature scheme, the private signing key is shared amongst a set of parties and only a quorum of those parties can generate a signature. Research on multiparty signing has been growing in popularity recently due to its application to cryptocurrencies. Most work has focused on reducing the number of rounds to two, and as a result: (a) are not fully simulatable in the sense of MPC real/ideal security definitions, and/or (b) are not secure under concurrent composition, and/or (c) utilize non-standard assumptions of different types in their proofs of security. In this paper, we describe a simple three-round multiparty protocol for Schnorr signatures that is secure for any number of corrupted parties; i.e., in the setting of a dishonest majority. The protocol is fully simulatable, secure under concurrent composition, and proven secure in the standard model or random-oracle model (depending on the instantiations of the commitment and zero-knowledge primitives). The protocol realizes an ideal Schnorr signing functionality with perfect security in the ideal commitment and zero-knowledge hybrid model (and thus the only assumptions needed are for realizing these functionalities). In our presentation, we do not assume that all parties begin with the message to be signed, the identities of the participating parties and a unique common session identifier, since this is often not the case in practice. Rather, the parties achieve consensus on these parameters as the protocol progresses.

A decentralized multi-authority CP-ABE scheme from LWE

As a cryptographic primitive supporting finer and richer access control, attribute-based encryption can provide more efficient, concise, secure and highly adaptive access control policies for cloud data, which has attracted the attention of many researchers. However, in a standard ABE scheme, the key can only be generated and issued by a central authority. The single authorization center has a heavy load and is vulnerable to attack. Once the center is paralyzed, it will bring serious security consequences. Multi-authorization center attribute encryption (MA-ABE) allows multiple parties to play an authoritative role, which can solve this problem.In this paper, we propose a MA-ABE scheme, which combines a global ID model, a two-stage sampling technique on a lattice and a monotonous linear secret sharing schemes (M-LSSS) to achieve a static security against arbitrary collusion in the random oracle model, in which the access policy of the scheme is expressed by DNF formula. Technically, our scheme is an improvement on the work of Datta et al. (2021), through this improvement, we can get shorter ciphertext and smaller key size.

Bitcoin as a Transaction Ledger: A Composable Treatment

Bitcoin is one of the most prominent examples of a distributed cryptographic protocol that is extensively used in reality. Nonetheless, existing security proofs are property-based, and as such they do not support composition. In this work, we put forth a universally composable treatment of the Bitcoin protocol. We specify the goal that Bitcoin aims to achieve as an instance of a parameterizable ledger functionality and present a UC abstraction of the Bitcoin blockchain protocol. Our ideal functionality is weaker than the first proposed candidate by Kiayias, Zhou, and Zikas [EUROCRYPT’16], but unlike the latter suggestion, which is arguably not implementable by the UC Bitcoin protocol, we prove that the one proposed here is securely UC-realized by the protocol assuming access to a global clock, to model time-based executions, a random oracle, to model hash functions, and an idealized network, to model message dissemination. We further show how known property-based approaches can be cast as special instances of our treatment and how their underlying assumptions can be cast in UC as part of the setup functionalities and without restricting the environment or the adversary.

Password authenticated key exchange-based on Kyber for mobile devices.

In this article, a password-authenticated key exchange (PAKE) version of the National Institute of Standards and Technology (NIST) post-quantum cryptography (PQC) public-key encryption and key-establishment standard is constructed. We mainly focused on how the PAKE version of PQC standard Kyber with mobile compatibility can be obtained by using simple structured password components. In the design process, the conventional password-based authenticated key exchange (PAK) approach is updated under the module learning with errors (MLWE) assumptions to add password-based authentication. Thanks to the following PAK model, the proposed Kyber.PAKE provides explicit authentication and perfect forward secrecy (PFS). The resistance analysis against the password dictionary attack of Kyber.PAKE is examined by using random oracle model (ROM) assumptions. In the security analysis, the cumulative distribution function (CDF) Zipf (CDF-Zipf) model is also followed to provide realistic security examinations. According to the implementation results, Kyber.PAKE presents better run-time than lattice-based PAKE schemes with similar features, even if it contains complex key encapsulation mechanism (KEM) components. The comparison results show that the proposed PAKE scheme will come to the fore for the future security of mobile environments and other areas.

Decentralized Anonymous IoT Data Sharing with Key-Private Proxy Re-Encryption

Secure and scalable data sharing is one of the main concerns of the Internet of Things (IoT) ecosystem. In this paper, we introduce a novel blockchain-based data-sharing construction designed to ensure full anonymity for both the users and the data. To share the encrypted IoT data stored on the cloud, users generate tokens, prove their ownership using zk-SNARKs, and target the destination address anonymously. To tackle the privacy concerns arising from uploading the data to the cloud, we use key-private re-encryption and share only the necessary information with the proxy. As the first time in the literature, we have integrated a token-based blockchain and a key private proxy re-encryption to achieve a fully anonymous data sharing scheme. Furthermore, we provide security proof of our proposed scheme is secure against existential forgery under chosen-plaintext attacks, under eDBDH assumption in the random oracle model.

A structure-preserving linearly homomorphic signature scheme with designated combiner.

Linearly homomorphic signature (LHS) allows the acquisition of a new legal signature using the homomorphic operation of the original signatures. However, the public composability of LHS also prevents it from being used in some scenarios where the combiner needs to be designated. The LZZ22 scheme designates a combiner and preserves the signature structure by having the signer and the designated combiner share a secret. However, LZZ22 is not secure enough because the secret is constant. Here, we first prove that there is a polynomial time adversary that can crack the secret in LZZ22 through multiple signature queries. Then, we propose a new scheme, which realizes all the functions of LZZ22 and fixes the security problem by changing the secret with the message. The proposed scheme is shown to be secure against existential forgery on adaptively chosen subspace attacks under the random oracle model. Finally, we detail how to apply our scheme to the proxy signature and perform it on a personal computer, and the results show that our scheme is efficient.

A logarithmic-sized accountable ring signature scheme in the standard model

Ring signature and group signature are two major cryptographic primitives providing users anonymity and authentication simultaneously. While both primitives enable any user to sign messages as a member of a set of users, the feature of ring signature is that a signer can choose a group in an ad-hoc manner, which is called a ring, by itself. Conversely, in group signature, a group membership is managed by some trusted third party, which is called a group manager, and an (appropriate) accountability is provided for the group manager to identify illegal anonymous signers. Accountable ring signature (ARS) is a cryptographic primitive combining the features of ring signature and group signature. ARS allows signers to choose their groups (rings) in an ad-hoc manner, and at the same time, maintain accountability by forcing them to select a designated opener who can identify them.In this paper, we propose the first ARS scheme with O(log⁡n) signature size in the standard model (without depending on the random oracle methodology), where n is the size of a ring. More precisely, we propose a new generic construction of ARS based on (standard) signature, (standard) public key encryption, non-interactive zero-knowledge proof system, somewhere perfectly binding hash function, and public key encryption with non-interactive opening. All building blocks for our ARS scheme can be obtained under the decisional linear (DLIN) assumption over bilinear groups.

A lightweight and secure protocol for teleworking environment.

The Internet has advanced so quickly that we can now access any service at any time, from any location. As a result of this capability, People around the world can benefit from the popularity and convenience of teleworking systems. Teleworking systems, however, are vulnerable to a range of attacks; as an unauthorized user enters the open communication line and compromises the whole system, that, in turn, creates a big hurdle for the teleworkers. Professional groups have presented numerous mechanisms for the security of teleworking systems to stop any harm, but there are still a lot of security issues like insider, stolen verifier, masquerade, replay, traceability and impersonation threats. In this paper, we propose that one of the security issues with teleworking systems is the lack of a secure authentication mechanism. In order to provide a secure teleworking environment, we have proposed a lightweight and secure protocol to authenticate all the participants and make the requisite services available in an efficient manner. The security analysis of the presented protocol has been investigated formally using the random oracle model (ROM) and ProVerif simulation and informally through illustration/attack discussions. Meanwhile, the performance metrics have been measured by considering computation and communication overheads. Upon comparing the proposed protocol with prior works, it has been demonstrated that our protocol is superior to its competitors. It is suitable for implementation because it achieved a 73% improvement in computation and 34% in communication costs.