Privileged Insider Research Articles

With privilege comes responsibility: Why some privileged insiders transform institutions for societal benefit

Why do some privileged insiders take action to transform institutions for broader societal benefit, while others do not? Privileged insiders are those who, because of their education, socio-economic background, formal position, citizenship, gender, and/or race, derive advantages from existing institutional arrangements. While their relative privilege places them in a better position to influence institutions, prior research would suggest that they are unlikely to do so without the prospect of personal gain. We find that privileged insiders feel compelled to engage in prosocial institutional transformation when they situate the problem not with others but with themselves, acknowledging their own complicity in structural injustice. They can navigate the emotional discomfort triggered by moral emotions by taking small pragmatic actions that lower their emotional distress and initiate a cycle of experimentation with change. Finally, we show that the practical evaluative dimension of agency plays a central role in shaping institutional change agency. Foregrounding the role of emotions in practical evaluation, we reveal how transformative templates for action emerge from a deliberative engagement with the self.

A Provably Secure Anonymous Authentication Protocol for Consumer and Service Provider Information Transmissions in Smart Grids

Smart grids integrate information technology, decision support systems, communication networks, and sensing technologies. All these components cooperate to facilitate dynamic power adjustments based on received client consumption reports. Although this brings forth energy efficiency, the transmission of sensitive data over the public internet exposes these networks to numerous attacks. To this end, numerous security solutions have been presented recently. Most of these techniques deploy conventional cryptographic systems such as public key infrastructure, blockchains, and physically unclonable functions that have either performance or security issues. In this paper, a fairly efficient authentication scheme is developed and analyzed. Its formal security analysis is carried out using the Burrows–Abadi–Needham (BAN) logic, which shows that the session key negotiated is provably secure. We also execute a semantic security analysis of this protocol to demonstrate that it can resist typical smart grid attacks such as privileged insider, guessing, eavesdropping, and ephemeral secret leakages. Moreover, it has the lowest amount of computation costs and relatively lower communication overheads as well as storage costs.

SEAF-IoD: Secure and efficient user authentication framework for the Internet of Drones

The Internet of Drones (IoD) stands as a rapidly advancing technology, finding applications across civilian, military, and industrial domains, facilitating the efficient execution of challenging tasks. However, the IoD environment introduces a plethora of security concerns. Drones, for example, must exchange critical information with control station servers and users through open and unsecured wireless channels. Consequently, protecting these sensitive data becomes paramount, leading to the development of SEAF-IoD, a secure and efficient user authentication framework for the IoD, as presented in this paper. SEAF-IoD relies on symmetric encryption, physical uncloneable functions (PUF), and hash functions. This framework empowers users to securely establish connections and obtain real-time data from specific drones deployed within the IoD environment. Furthermore, the utilization of PUF holds great promise in achieving cost-effective security. PUF obviates the necessity to store confidential keys in device memory, offering a potential alternative for establishing a more secure and cost-efficient authentication framework for IoD systems. PUF empowers the SEAF-IoD to enhance its resilience against privileged insider attacks and drone/device capture attempts. To ensure the robustness of SEAF-IoD, it undergoes rigorous validation using BAN logic and Scyther simulation. Furthermore, an informal analysis affirms that SEAF-IoD fulfills critical security requirements and effectively thwarts various adversarial threats, including privileged insider, replay, and impersonation attacks. A comprehensive comparison of SEAF-IoD against existing schemes highlights its resilience and superiority in safeguarding IoD environments.

A three-factor mutual authentication scheme for telecare medical information system based on ECC

In critical pandemic situations, the Telecare Medical Information System (TMIS) is a technological invention that offers secure and authentic patient registration and medical services remotely. Wireless Body Area Network (WBAN) uses TMIS to facilitate users/patients with remote medical services. Numerous schemes for authentication have been developed for secure and authentic communication to prevent security attacks encompassing replay, impersonation, and forgery attacks. Ryu et al. have proposed an ECC-based mutual authentication scheme in 2022. Nevertheless, through security scheme analysis, we have evidenced that Ryu et al.’s scheme has a trapdoor for insider attacks and privileged insider attacks. Their proposed scheme offers no assurance of server anonymity. In this paper, we propose a three-factor authentication system based on ECC that protects sensitive patient data from getting out during communication and protects against different types of security attacks. We have conducted an informal security analysis to verify that our scheme withstands security attacks.

A blockchain-based anonymous reporting system with no central authority: Architecture and protocol

Blockchain technology has emerged as a compelling field of study over the past decade. Nevertheless, certain blockchain-based protocols, particularly those reliant on permissioned blockchains, continue to be under the governance of a central authority (CA). This central authority possesses extensive control capabilities, including the facilitation of user network access, as well as the establishment, connection, and revocation of users to and from the network. Consequently, the majority of policies within these protocols are centrally administered by a singular party. This paper introduces an architectural framework and a specific protocol denoted as the “Anonymous Reporting System with No Central Authority” (ARSnCA) on a public blockchain infrastructure. This design aims to mitigate the challenges posed by untrusted privileged insiders to the ARSnCA. It is hypothesized that this approach can enhance system reliability, fault tolerance, and foster trust among network members. To eliminate the central authority, a concept termed the virtual blockchain (VBC) is implemented as an embedded permissioned blockchain within a permissionless blockchain. Following the removal of the CA, the authorities previously held by the central authority are transferred to the members of the VBC. Comparative analysis and evaluation of the ARSnCA protocol demonstrate a performance advantage, with speeds that are 62% and 92% faster than reporting protocols based on ring signatures and other protocols included in the comparison.

Provably Secure Lightweight Mutual Authentication and Key Agreement Scheme for Cloud-Based IoT Environments.

A paradigm that combines cloud computing and the Internet of Things (IoT) allows for more impressive services to be provided to users while addressing storage and computational resource issues in the IoT environments. This cloud-based IoT environment has been used in various industries, including public services, for quite some time, and has been researched in academia. However, various security issues can arise during the communication between IoT devices and cloud servers, because communication between devices occurs in open channels. Moreover, issues such as theft of a user's IoT device or extraction of key parameters from the user's device in a remote location can arise. Researchers interested in these issues have proposed lightweight mutual authentication key agreement protocols that are safe and suitable for IoT environments. Recently, a lightweight authentication scheme between IoT devices and cloud servers has been presented. However, we found out their scheme had various security vulnerabilities, vulnerable to insider, impersonation, verification table leakage, and privileged insider attacks, and did not provide users with untraceability. To address these flaws, we propose a provably secure lightweight authentication scheme. The proposed scheme uses the user's biometric information and the cloud server's secret key to prevent the exposure of key parameters. Additionally, it ensures low computational costs for providing users with real-time and fast services using only exclusive OR operations and hash functions in the IoT environments. To analyze the safety of the proposed scheme, we use informal security analysis, Burrows-Abadi-Needham (BAN) logic and a Real-or-Random (RoR) model. The analysis results confirm that our scheme is secure against insider attacks, impersonation attacks, stolen verifier attacks, and so on; furthermore, it provides additional security elements. Simultaneously, it has been verified to possess enhanced communication costs, and total bit size has been shortened to 3776 bits, which is improved by almost 6% compared to Wu et al.'s scheme. Therefore, we demonstrate that the proposed scheme is suitable for cloud-based IoT environments.

Cryptanalysis of Secure ECC-Based Three Factor Mutual Authentication Protocol for Telecare Medical Information System

Telecare Medical Information System (TMIS) is gaining importance in the present COVID-19 crisis. TMIS as a technology, offers patients a range of remote medical services, incorporated into Wireless Body Area Network (WBAN). The patient’s medical report is confidentially transmitted over an open channel in TMIS environments. An attacker may attempt to compromise the security, such as forgery, replay, and impersonation attacks. To ensure secure communication, various authentication solutions have been introduced for TMIS. Biometrics and Elliptic Curve Cryptography-based mutual authentication protocol was recommended by Sahoo et al. in 2020 and is proved to have some loopholes in the protocol. We discovered, however, Sahoo et al. method is unable to prevent privileged insider attacks and insider attacks along with patient anonymity. Jongseok Ryu et al. recommended a ECC based three-factor mutual authentication protocol and ensures patient’s confidentiality for TMIS with proof of informal analysis. They have also performed formal security studies utilizing the Automated Validation of Internet Security Protocols and Applications (AVISPA), the Burrows-Abadi-Needham (BAN) logic and Real-Or-Random (ROR) model. However, we have reviewed the Jongseok Ryu et al.’s proposal. Based on his attacker model, we have examined that this scheme is unsafe against Message Substitution Attacks, Man-in-the-Middle attacks, Session Key Disclosure attacks, Privileged Insider attacks, and Stolen verifier attacks. we suggest a technique to be safe from the above security threats.

A probably secure biometric‐based authentication and key agreement scheme for Internet of Drones

AbstractThe Internet of Drones (IoD) is one of the world's most recent and innovative technology. Drones are most prominent IoT (Internet of Things) gadgets and their applications span from commercial to domestic. The sensitive data stored in drones has increased the demand for the security of communication in the IoD. As a result, numerous authentication and key agreement techniques have been developed to proffers secure communication among the entities of the IoD network. However, after scrutinizing the security of these protocols, many IoD protocols were observed to be susceptible to different cryptographic attacks. This has enhanced the necessity for an improved and efficient authentication scheme in IoD. In this article, we first investigate Zhang et al.'s approach and demonstrate that although it offers security verification, it has certain design problems. It is, furthermore, shown to be vulnerable to privileged insider, offline password guessing, and stolen smart device attacks. Second, we propose a novel biometric‐based scheme that includes countermeasures to protect against these flaws. The security of the mechanism is examined under real or random oracle model, informal security analysis and scyther simulation for numerous cryptographic assaults. Also, the performance analysis substantiates the competency of the proposed scheme corresponding to computation and communication cost with existing schemes.

Enhancing the Security: A Lightweight Authentication and Key Agreement Protocol for Smart Medical Services in the IoHT

The Internet of Things (IoT) has witnessed significant growth with advancements in Internet and wireless technologies. In the medical field, the Internet of Health Things (IoHT) has emerged as an extension of the IoT, enabling the exchange of remote data and real-time monitoring of patients’ health conditions. Through the IoHT, doctors can promptly provide diagnoses and treatment for patients. As patient data are transmitted over public channels, security issues may arise, necessitating security mechanisms. Recently, Amintoosi et al. proposed an authentication protocol for smart medical services in the IoHT. However, their protocol exhibited security weaknesses, including vulnerabilities to privileged insider attacks. To address the security concerns, we propose an enhanced authentication and key agreement protocol. The security of our protocol is rigorously analyzed using the Real-Or-Random model, informal security analysis, and the AVISPA tool. Finally, the results of our analysis demonstrate that our proposed protocol ensures sufficient security while maintaining a performance level similar to existing protocols.

Elliptic Curve Cryptography-Based Scheme for Secure Signaling and Data Exchanges in Precision Agriculture

Precision agriculture encompasses automation and application of a wide range of information technology devices to improve farm output. In this environment, smart devices collect and exchange a massive number of messages with other devices and servers over public channels. Consequently, smart farming is exposed to diverse attacks, which can have serious consequences since the sensed data are normally processed to help determine the agricultural field status and facilitate decision-making. Although a myriad of security schemes has been presented in the literature to curb these challenges, they either have poor performance or are susceptible to attacks. In this paper, an elliptic curve cryptography-based scheme is presented, which is shown to be formally secure under the Burrows–Abadi–Needham (BAN) logic. In addition, it is semantically demonstrated to offer user privacy, anonymity, unlinkability, untraceability, robust authentication, session key agreement, and key secrecy and does not require the deployment of verifier tables. In addition, it can withstand side-channeling, physical capture, eavesdropping, password guessing, spoofing, forgery, replay, session hijacking, impersonation, de-synchronization, man-in-the-middle, privileged insider, denial of service, stolen smart device, and known session-specific temporary information attacks. In terms of performance, the proposed protocol results in 14.67% and 18% reductions in computation and communication costs, respectively, and a 35.29% improvement in supported security features.

Rotating behind security: an enhanced authentication protocol for IoT-enabled devices in distributed cloud computing architecture

With the continuous progress of the Internet of Things (IoT) technology, IoT devices have gradually penetrated all aspects of life. However, due to rapid data growth, IoT devices with limited memory resources cannot store massive data. Cloud computing is an Internet-centric network that can provide security services and data storage. The combination of IoT devices with cloud computing considerably promotes resource sharing, facilitates users’ access to information at any time, and provides users with corresponding cloud computing services on time. Because the information transmitted through public channels is easily intercepted, tampered with, and eavesdropped on by malicious attackers. As a result, users’ and servers’ private information are disclosed. Numerous scholars have proposed different authentication protocols in this environment to protect the communications between users and servers. Amin et al. devised a smart card based authentication protocol. Unfortunately, Kang et al. demonstrated that their protocol was insecure. Huang et al. discovered Kang et al.’s improvement also has security flaws and then designed a protocol to enhance security. In this paper, we first show that Huang et al.’s protocol cannot resist privileged insider and temporary value disclosure attacks. Afterward, we propose an enhanced protocol based on their protocol. Finally, we use formal/informal security analysis to demonstrate the security of the improved protocol. The comparison results are indicated that our protocol has lower computational and communication costs under the same security level.

An Improved Lightweight User Authentication Scheme for the Internet of Medical Things.

The Internet of Medical Things (IoMT) is used in the medical ecosystem through medical IoT sensors, such as blood glucose, heart rate, temperature, and pulse sensors. To maintain a secure sensor network and a stable IoMT environment, it is important to protect the medical IoT sensors themselves and the patient medical data they collect from various security threats. Medical IoT sensors attached to the patient's body must be protected from security threats, such as being controlled by unauthorized persons or transmitting erroneous medical data. In IoMT authentication, it is necessary to be sensitive to the following attack techniques. (1) The offline password guessing attack easily predicts a healthcare administrator's password offline and allows for easy access to the healthcare worker's account. (2) Privileged-insider attacks executed through impersonation are an easy way for an attacker to gain access to a healthcare administrator's environment. Recently, previous research proposed a lightweight and anonymity preserving user authentication scheme for IoT-based healthcare. However, this scheme was vulnerable to offline password guessing, impersonation, and privileged insider attacks. These attacks expose not only the patients' medical data such as blood pressure, pulse, and body temperature but also the patients' registration number, phone number, and guardian. To overcome these weaknesses, in the present study we propose an improved lightweight user authentication scheme for the Internet of Medical Things (IoMT). In our scheme, the hash function and XOR operation are used for operation in low-spec healthcare IoT sensor. The automatic cryptographic protocol tool ProVerif confirmed the security of the proposed scheme. Finally, we show that the proposed scheme is more secure than other protocols and that it has 266.48% better performance than schemes that have been previously described in other studies.

Distributed auditing protocol for untraceable transactions

Data integrity is a property that cloud service providers (CSPs) have focused on. The data integrity checking is assigned to third-party auditors (TPAs) to avoid invalid data storage in CSPs. Nevertheless, this type of mechanism is vulnerable to many threats, including insider/outsider adversaries. Moreover, several threats still exist with its presence, such as deleting, changing, or destroying the recorded data. The study presents a blockchain-based distributed auditing (BB-DA) protocol for auditing confidential/untraceable transactions in a distributed manner. The BB-DA protocol provides message/transaction confidentiality, user privacy, and security against privileged insider adversaries, who want to create disorder in the auditing process by refusing to sign/audit, and those who aim to do so in the BB-DA protocol will fail even if they cooperate. To provide message confidentiality and security against malicious insiders, the ElGamal cryptosystem is used in the BB-DA protocol, and to avoid destroying the submitted data (transactions) by CSPs, the blockchain is used as a distributed and immutable database in the BB-DA protocol. The Zerocoin is applied in the BB-DA protocol for providing user untraceability and anonymity. The security analysis of the BB-DA protocol proves that the offered protocol is secure against the key-only, known message, and chosen message attacks. Additionally, the analysis indicates that it provides security against malicious insiders who want to learn any knowledge about corresponded transactions or break users’ anonymity. The paper’s comparison and evaluation show that the BB-DA offers more features and is more efficient than other auditing protocols.

Improved and Provably Secure ECC-Based Two-Factor Remote Authentication Scheme with Session Key Agreement

The remote authentication scheme is a cryptographic protocol incorporated by user–server applications to prevent unauthorized access and security attacks. Recently, a two-factor authentication scheme using hard problems in elliptic curve cryptography (ECC)—the elliptic curve discrete logarithm problem (ECDLP), elliptic curve computational Diffie–Hellman problem (ECCDHP), and elliptic curve factorization problem (ECFP)—was developed, but was unable to address several infeasibility issues while incurring high communication costs. Moreover, previous schemes were shown to be vulnerable to privileged insider attacks. Therefore, this research proposes an improved ECC-based authentication scheme with a session key agreement to rectify the infeasible computations and provide a mechanism for the password change/update phase. The formal security analysis proves that the scheme is provably secure under the random oracle model (ROM) and achieves mutual authentication using BAN logic. Based on the performance analysis, the proposed scheme resists the privileged insider attack and attains all of the security goals while keeping the computational costs lower than other schemes based on the three hard problems. Therefore, the findings suggest the potential applicability of the three hard problems in designing identification and authentication schemes in distributed computer networks.

Provably Secure PUF-Based Lightweight Mutual Authentication Scheme for Wireless Body Area Networks

Wireless body area networks (WBANs) are used in modern medical service environments for the convenience of patients and medical professionals. Owing to the recent COVID-19 pandemic and an aging society, WBANs are attracting attention. In a WBAN environment, the patient has a sensor node attached to him/her that collects patient status information, such as blood pressure, blood glucose, and pulse; this information is simultaneously transmitted to his/her respective medical professional through a gateway. The medical professional receives and checks the patient’s status information and provides a diagnosis. However, sensitive information, including the patient’s personal and status data, are transmitted via a public channel, causing security concerns. If an adversary intercepts this information, it could threaten the patient’s well-being. Therefore, a secure authentication scheme is essential for WBAN environments. Recently, Chen et al. proposed a two-factor authentication scheme for WBANs. However, we found out Chen et al.’s scheme is vulnerable to a privileged insider, physical cloning, verification leakage, impersonation, and session key disclosure attacks. We also propose a secure physical-unclonable-function (PUF)-based lightweight mutual authentication scheme for WBANs. Through informal security analysis, we demonstrate that the proposed scheme using biometrics and the PUF is safe against various security attacks. In addition, we verify the security features of our scheme through formal security analyses using Burrows–Abadi–Needham (BAN) logic, the real-or-random (RoR) model, and the Automated Validation of Internet Security Protocols and Applications (AVISPA). Furthermore, we evaluate the security features, communication costs, and computational costs of our proposed scheme and compare them with those of other related schemes. Consequently, our scheme is more suitable for WBAN environments than the other related schemes.

The Participation of Marginal and Liminal Groups in Secondary State Formation under the Third Dynasty of Ur

Abstract The Ur III period (2112–2004 BC) provides rich opportunities to evaluate the contributions of marginal and liminal groups to the political economy of the era, and to re-assess our understanding of what constituted such groups in an era of early state formation. These opportunities arise in part from the well preserved and detailed administrative corpora at major provincial centers like Umma and Ĝirsu, as well as from significant centers of royal activity like Puzriš-Dagan and Iri-sagrig. These archives document many of the activities of the two groups on which this article focuses: the large body of marginalized dependent laborers (Sumerian ĝuruš) who performed a great deal of the agricultural work in Mesopotamia, and the liminal figures who frequent our records, often associated with pastoralism, and who are identified as Amorites (Sumerian Mar-tu). The former group I identify as “insiders” who were socio-economically marginalized, and the latter group I identify as “outsiders” who occasionally had the opportunity to become privileged insiders. Our tendency in the study of early agrarian societies to regard pastoralists as “outsiders” allows for a critique of how we identify and describe liminal groups; and this has added significance for how we understand the state building projects of the Third Dynasty of Ur.

SGXAP: SGX-Based Authentication Protocol in IoV-Enabled Fog Computing

With the maturity and popularization of the Internet of Things, we saw the emergence of the Internet of Vehicles. This collects and processes real-time traffic information, alleviates traffic congestion, and realizes intelligent transportation. However, sensitive information, such as real-time driving data of vehicles, are transmitted on public channels, which are easily to steal and manipulate for attackers. In addition, vehicle communications are vulnerable to malicious attacks. Therefore, it is essential to design secure and efficient protocols. Many studies have adopted asymmetric cryptosystems and fog computing to in this environment, but most of them do not reflect the advantages of fog nodes, which share the computational burden of cloud servers. Therefore, it is challenging to design a protocol that effectively uses fog nodes. In this paper, we design an authentication protocol based on a symmetric encryption algorithm and fog computing in the Internet of Vehicles. In this protocol, we first propose a four-layer architecture that significantly reduces the computational burden of cloud servers. To resist several well-known attacks, we also apply Intel software guard extensions to our protocol. This is because it can resist privileged insider attacks. We prove the security of the proposed protocol through the Real-Or-Random model and informal analysis. We also compare the performance of the proposed protocol with recent protocols. The results show better security and a lower computational cost.

An Improved Authentication Scheme for Digital Rights Management System

With the increasing number and popularity of digital content, the management of digital access rights has become an utmost important field. Through digital rights management systems (DRM-S), access to digital contents can be defined and for this, an efficient and secure authentication scheme is required. The DRM authentication schemes can be used to give access or restrict access to digital content. Very recently in 2020, Yu et al. proposed a symmetric hash and xor-based DRM and termed their system to achieve both security and performance efficiency. Contrarily, in this study, we argue that their scheme has several issues including nonresistance to privileged insider and impersonation attacks. Moreover, it is also to show in this study that their scheme has an incorrect authentication phase and due to this incorrectness, the scheme of Yu et al. lacks user scalability. An improved scheme is then proposed to counter the insecurities and incorrectness of the scheme of Yu et al. We prove the security of the proposed scheme using BAN logic. For a clear picture of the security properties, we also provide a textual discussion on the robustness of the proposed scheme. Moreover, due to the usage of symmetric key-based hash functions, the proposed scheme has a comparable performance efficiency.

Secure ECC-Based Three-Factor Mutual Authentication Protocol for Telecare Medical Information System

In the recent COVID-19 situation, Telecare Medical Information System (TMIS) is attracting attention. TMIS is one of the technologies used in Wireless Body Area Network (WBAN) and can provide patients with a variety of remote healthcare services. In TMIS environments, sensitive data of patients are communicated via an open channel. An adversary may attempt various security attacks including impersonation, replay, and forgery attacks. Therefore, numberous authentication schemes have been suggested to provide secure communication for TMIS. Sahoo <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">et al.</i> proposed a mutual authentication scheme based on biometrics and Elliptic Curve Cryptography (ECC) in 2020. However, we find out that Sahoo <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">et al.</i> ’s scheme cannot resist insider and privileged insider attacks and cannot guarantee patient anonymity. In this paper, we propose a secure ECC-based three-factor mutual authentication protocol that guarantees the privacy of patients for TMIS. We conduct informal security analysis to prove that our protocol is secure from various security attacks. In addition, we perform formal security analyses using the Automated Validation of Internet Security Protocols and Applications (AVISPA), Burrows-Abadi-Needham (BAN) logic, and the Real-Or-Random (ROR) model. Furthermore, we assess our protocol’s performance and compare it to other protocols. As a result, our protocol has lower communication costs, and better security features compared to related existing protocols. Therefore, our protocol is more appropriate for TMIS environments than other related protocols.

A Provably Secure Three-Factor Authentication Protocol Based on Chebyshev Chaotic Mapping for Wireless Sensor Network

Wireless sensor network has been widely used and plays a vital role in the Internet of Things, smart cities, military, and other fields, and its security has also attracted the attention of many researchers. In view of the security defects in Shin and Kwon’s scheme such as failure to provide three-factor security, lack of anonymity and untraceability, user impersonation attack, desynchronization attack and privileged insider attack, we suggest an improved provably secure three-factor user authentication scheme based on Chebyshev chaotic mapping for wireless sensor network, which employs fuzzy verifier technique to prevent attacker from offline guessing attack on user identity and password when the stolen/lost smartcard is acquired by the attacker. During the authentication phase, a dynamic identity mechanism is used to ensure the anonymity of the user and sensor to prevent desynchronization attack, and the Chebyshev chaotic mapping is introduced to improve security and reduce computation overhead. The rigorous security proof under the random oracle model and the formal verification via ProVerif show that our protocol overcomes the weaknesses in Shin and Kwon’s scheme. In addition, by comparing the performance of our proposed scheme with that of others, we demonstrate that our proposal not only solves the security risks of Shin and Kwon.’s protocol, but also achieves a better tradeoff between security and efficiency, therefore, it is more suitable for user authentication in wireless sensor network environments.