ORIGINAL RESEARCH article

Front. Phys., 26 November 2025

Sec. Social Physics

Volume 13 - 2025 | https://doi.org/10.3389/fphy.2025.1647836

Efficient and secure authentication scheme with user anonymity based on cloud computing in 6G

  • 1. School of Telecommunications Engineering, Xidian University, Xi’an, China

  • 2. Luoyang Institute of Science and Technology Library, Luoyang, China

Abstract

With the rapid development of 6G and the widespread adoption of cloud computing technologies, security issues in distributed cloud computing systems have become increasingly critical. Ensuring user anonymity, legitimate device access, communication security, and efficient authentication has emerged as an urgent challenge. To address these issues, this paper proposes an anonymous, secure, and efficient authentication scheme for 6G cloud computing. The scheme supports both user authentication and device access authentication by integrating Chebyshev chaotic mapping with a multi-factor authentication mechanism. It ensures secure verification of user identities and access devices and protects subsequent session keys. Furthermore, a Physical Unclonable Function (PUF) is deployed on the device side to leverage unique hardware features, providing strong identity recognition and resistance to physical attacks while improving system authentication efficiency. Performance evaluations demonstrate that the proposed scheme reduces computational overhead by an average of 30.45% and communication overhead by an average of 16.32% compared with the baseline scheme. These results confirm that the proposed scheme significantly enhances communication security between authorized users, legitimate devices, and cloud servers in 6G cloud computing environments. By combining chaotic mapping, multi-factor authentication, and PUF-based verification, the scheme achieves robust security, lightweight computation, and strong scalability suitable for next-generation distributed cloud systems.

1 Introduction

With commercialization of the fifth-generation (5G) mobile communication network, major global telecom operators and technology companies are now shifting their research and development focus to the sixth-generation (6G) network. 6G is envisioned not only as a faster, lower-latency and more widely covered communication platform, but also as a transformative infrastructure that enables the true interconnection of everything. This integration is expected to trigger profound societal transformation and technological innovation, laying the foundation for a new era of intelligent infrastructure.

In this transformative process, cloud computing—serving as a core supporting technology—will demonstrate greater capabilities and wider application scenarios in the 6G. Benefiting from 6G’s high data transmission rates, ultra-low latency, high reliability and edge-distributed architecture, cloud computing will overcome the limitations of traditional networks in bandwidth, delay and resource allocation. This will extend computing and service capabilities toward the network edge, enabling faster data processing, lower service response times and more intelligent decision-making [].

In the realm of smart cities, the integration of cloud computing and 6G can support real-time acquisition and analysis of massive data from high-definition video surveillance, intelligent traffic control systems and public safety management, enabling intelligent scheduling of urban resources and rapid response to events. In the industrial internet, cloud platforms can monitor the operational status of factory equipment and production line data in real time, enabling predictive maintenance and significantly improving production efficiency and equipment utilization []. In autonomous driving scenarios, vehicles can maintain high-speed communication with the cloud via 6G networks, uploading sensor data for real-time cloud-based processing to enhance perception and decision-making capabilities. In telemedicine, doctors can use ultra-high-definition imaging and real-time interactive systems to guide surgeries or monitor the health of remote patients, greatly alleviating the imbalance of medical resource distribution. For immersive experiences such as Virtual Reality (VR)/Augmented Reality (AR) and holographic communication, complex graphics rendering and scene generation can be handled in the cloud and transmitted back to the user terminal via the 6G network, ensuring smooth and immersive user experiences [].

However, as cloud computing continues to evolve, ensuring user privacy and data security within cloud environments has become an urgent issue. In 6G, the scale of user and device access is expected to reach unprecedented levels. Traditional authentication mechanisms may face significant challenges, including excessive latency and computational overhead, in handling such large-scale user access and device authentication. This is particularly true in cloud computing environments, where authentication processes may involve extensive data processing and transmission, placing greater demands on authentication efficiency []. Moreover, in traditional identity authentication mechanisms, users may need to disclose certain identity information during the authentication process, which poses risks of privacy leakage or exploitation by attackers. Therefore, there is a pressing need to design a cloud computing-based anonymous and secure authentication scheme that not only protects user privacy but also significantly enhances authentication efficiency.

1.1 Related work

At present, extensive research has been conducted both domestically and internationally in the fields of authentication and key agreement, resulting in the proposal of various protocol schemes aimed at ensuring the security of authentication processes and data communications [].

Parai et al. [] based on Gupta’s [] research, proposed an identity-based three-party authentication key negotiation protocol for resource-constrained IoT devices. They tested and estimated the execution time of the protocol on a Raspberry Pi 4 device, covering security levels from 80 bits to 256 bits. However, since the protocol is based on bilinear pairings, it still has a high computational cost. In 2023, Mookherji et al. [] proposed a semi-centralized architecture and a certification and key negotiation scheme for smart healthcare systems. In this scheme, the cloud server delegates user registration functionality to fog servers, and users can complete registration by sending requests to fog servers. This scheme claims to effectively address the threat of server single-point compromise. However, fog servers are typically deployed close to the device edge layer and are considered untrusted. Compared to centralized cloud servers, fog servers have higher key management costs and challenges. Qiu et al. [] addressed the imbalance between practicality and security in three-factor authentication by proposing a lightweight mobile device authentication scheme using chaotic mapping. The scheme utilizes fuzzy verifiers and honeyword techniques to resist offline password guessing attacks. In 2021, Lin et al. [] introduced an authentication protocol tailored for 5G healthcare IoT systems, enabling patients to access multiple remote medical services using paired credentials. However, due to the absence of timestamps and the use of a public authentication parameter, the scheme is susceptible to Denial of Service (DoS) attacks. Additionally, storing users’ private keys in plaintext on the smart card leaves it vulnerable to card theft attacks. To address identity verification in Wireless Body Area Networks (WBAN), Alzahrani et al. [] introduced a lightweight protocol that facilitates session key generation between sensor and hub nodes. Nevertheless, it lacks comprehensive mutual authentication among access points, hubs, and sensors, limiting its practical deployment. Nyangaresi et al. [] proposed a cheme to secure interactions between body sensor units and administrators in WBAN scenarios, achieving forward secrecy through session key generation. Yet, the protocol fails to preserve user anonymity when the gateway node acts as an insider adversary.

Xie et al. [] designed a scheme for patient monitoring systems using elliptic curve cryptography (ECC) and validated its security via formal analysis. However, it does not implement mutual authentication between sensor and relay nodes. Deebak et al. [] designed a framework for cloud-assisted medical cyber-physical systems based on Chebyshev chaotic maps. A major weakness lies in the registration phase, where user credentials are transmitted in plaintext to the gateway, risking identity exposure. Tu et al. [] also proposed EAKE-WCI, an anonymous authentication protocol for wearable healthcare devices in cloud environments. While the scheme ensures mutual authentication among users, devices, and servers, it lacks adequate password protection during login, making it vulnerable to guessing attacks. Edwards et al. [] introduced a distributed authentication framework, incorporating physical tokens, biometrics, and cryptographic keys to validate user identity. Lee et al. [] developed a three-factor authentication method tailored for sensor-based devices operating in IoT settings. Their approach utilizes Physical Unclonable Function (PUF) and honeypot mechanisms to mitigate threats such as ID/password guessing, brute-force, and eavesdropping attacks. Mirsaraei et al. [] introduced another three-factor authentication protocol suitable for IoT applications, employing elliptic curve cryptography and smart cards for user registration and identity verification within private blockchain environments. This design is particularly effective for resource-constrained IoT devices. Ghose et al. [] presented two-factor authentication protocol. Initial verification step is based on traditional credentials (username and password), while the second step leverages persistent associations between the user’s device and an auxiliary unit. Ahmad et al. [] introduced BAuth-ZKP, a multi-factor authentication protocol designed for smart city. By utilizing blockchain smart contracts, the scheme enables secure user verification without revealing personal identity information. Braeken et al. [] developed a two-way multi-factor authentication and key exchange mechanism aimed at facilitating secure access to remote sensor nodes. Their approach ensures real-time data retrieval and defends against semi-trusted intermediaries, while preserving user anonymity and untraceability, and mitigating risks from session-specific data leakage. In the healthcare sector, Miao et al. [] proposed a three-factor authentication protocol for medical IoT systems, leveraging blockchain to manage identity-related data and applying Chebyshev chaotic maps to enhance login and authentication robustness. Zhang et al. [] presented an ECC-based three-factor scheme involving credentials, passwords, and biometrics for secure interaction among administrators, gateways, and industrial IoT devices. This protocol supports identity revocation and online updates, adapting to dynamic industrial requirements. To enhance cloud network security, Bernard et al. [] designed a mutual authentication protocol utilizing visual cryptography. The approach employs confidential mappings—specifically visual encryption and challenge-response pairs—along with credential-based verification to counteract weaknesses in traditional cryptographic algorithms. Despite its enhanced security features, the scheme incurs significant computational cost, which limits its efficiency on resource-limited platforms.

PUF is an emerging cryptographic primitive known for its strong resistance to duplication. Min et al. [] designed an authentication approach that integrates PUF with a dynamic identity mechanism, effectively safeguarding device identities and enhancing privacy at the hardware level. In a subsequent work, Aman et al. [] developed a PUF-based mutual authentication protocol, enabling secure communication between devices and servers, as well as among devices themselves, thereby expanding its applicability. Shah et al. [] presented a PUF-enabled authentication mechanism that employs challenge–response pairs and incorporates the AES encryption algorithm to improve overall system security. Zhu et al. [] introduced a PUF-driven authentication protocol specifically designed for RFID environments, addressing critical security concerns such as unclonability and traceability, while also supporting mutual authentication. In summary, current authentication schemes still have security vulnerabilities and incur high computational and communication costs [].

1.2 Contributions

In this paper, we propose a cloud-based anonymous and secure authentication scheme. Our approach enables mutual authentication between users and access devices, allowing them to securely establish a reliable shared session key. Communication efficiency is also considered in the proposed scheme. The main contributions of this work can be summarized as follows:

The security of the proposed scheme is proven under the Random Oracle Model. Additionally, security analysis demonstrates that the proposed scheme can withstand common attacks. Performance comparisons show that the proposed scheme addresses the security shortcomings of existing solutions and has lower computational and communication overhead.

  • This paper proposes an anonymous, secure, and efficient authentication scheme for cloud-based in 6G. The proposed scheme employs Chebyshev chaotic mapping and PUF to construct a lightweight key agreement mechanism. Additionally, by integrating hash functions and a session key update strategy, the scheme ensures user anonymity and forward security of session data. PUF technology is incorporated on the device side, leveraging its unique hardware characteristics to provide robust identity verification and resistance to physical attacks.

  • The security of the proposed scheme is formally proven under the random oracle model. Furthermore, the security analysis demonstrates that the scheme is resilient against common types of attacks. Performance comparisons indicate that the proposed solution addresses the security weaknesses of existing schemes while maintaining low computation and communication overhead.

1.3 Paper organization

The structure of this paper is arranged as follows. Section 2 outlines the foundational concepts relevant to the proposed scheme. Section 3 details the authentication protocol in depth. Sections 4 and 5 are dedicated to the security assessment and efficiency analysis of the scheme. The final section concludes the study and highlights potential avenues for future exploration.

2 Preliminaries

This section presents the relevant background of proposed scheme, with detailed explanations provided below.

2.1 System architecture

As shown in Figure 1, cloud-based authentication protocol proposed in this paper consists of three main components: cloud servers, users, and access devices. These components are interconnected via a high-speed, highly reliable 6G core network, forming a secure communication architecture that supports large-scale heterogeneous device access.

FIGURE 1

Cloud Servers: Serving as the central management entities, cloud servers are responsible for identity authentication, key management, secure storage, and data processing.

Users: It refers to individuals or organizations utilizing the system services, including system administrators, household users, and industrial control personnel. Users initiate authentication requests via terminals to access cloud resources or remotely control access devices.

Access Devices: These are intelligent terminal devices deployed in various application environments, equipped with communication, control, and response capabilities. Beyond simply connecting to the cloud platform, they can execute task instructions, report status information, and trigger predefined actions. Depending on the application scenario, access devices include the following:

  • Industrial control terminals, actuators, and robots in factory settings, enabling automated operations and status feedback;

  • Smart cameras, locks, and lighting systems in home environments, allowing remote control and environmental regulation;

  • Embedded intelligent devices in fields such as healthcare, transportation, and energy, capable of edge-level sensing, state synchronization, and policy-based responses.

Access devices engage in mutual authentication with both users and cloud servers via the proposed protocol, ensuring that all communications occur in a trusted and secure environment, thereby preventing unauthorized access and data leakage.

Leveraging the high bandwidth and low latency characteristics of 6G core network, proposed system achieves strong security guarantees while meeting real-time performance requirements and supporting massive connectivity.

2.2 Chebyshev chaotic mapping

Given an integer and a variable , where , can be defined as:

From Equation 1, the recursive formula for Chebyshev polynomials is derived as Equation 2 [38]:

According to the above formulas, Chebyshev polynomials satisfy the semi-group property. That is, for any two positive integers , and , Equation 3 holds:

The semigroup property [43]: For and , the enhanced Chebyshev polynomial is defined as Equation 4:where is a large prime number. Based on this definition, the enhanced Chebyshev polynomial still satisfies the semi-group property, expressed as Equation 5:

Chebyshev Polynomial-Based Diffie-Hellman Problem (): For any positive integers and , and any , given and , it is computationally hard to derive , due to the semi-group property of Chebyshev polynomials modulo a large prime [3941].

2.3 Physical unclonable function

Physical Unclonable Function (PUF) is cryptographic primitives embedded as circuit modules within chips, serving as hardware security mechanisms. They exploit random physical variations introduced during manufacturing, which are uncontrollable and unique to each device. This inherent randomness ensures that producing two identical PUF-enabled devices is practically impossible. Consequently, PUF is increasingly utilized in information security, particularly for lightweight device authentication and as novel factors in multi-factor authentication protocols.

PUF operates using a challenge-response mechanism: input signals, termed challenges, are processed by the PUF to generate unique responses, collectively forming Challenge-Response Pairs (CRPs). In a typical authentication setup, the PUF circuit is embedded within the authentication server. During registration, the server receives challenges from authenticating devices, processes them via its PUF module, and generates corresponding responses, which can be stored as CRPs in a database for future verification. Due to the uniqueness and tamper-resistance of PUF, these responses remain consistent and unforgeable. An ideal PUF satisfies three critical properties:

  • Uniqueness: Identical challenges input to the same PUF always yield identical responses, while different PUFs produce different responses even when presented with identical challenges.

  • One-wayness: Given a known response, it is computationally infeasible to derive the original challenge that produced it.

  • Tamper-resistance: Physical attacks damage the PUF’s physical structure, thereby disrupting its challenge-response behavior and rendering its authentication function unusable.

These characteristics make PUF particularly suitable for secure, hardware-level identity verification in resource-constrained environments.

3 Proposed scheme

This section provides a comprehensive explanation of the proposed scheme, which is built upon an enhanced Chebyshev chaotic map. Table 1 outlines the symbols and cryptographic operations utilized throughout the scheme.

TABLE 1

SymbolDescription
Cloud server
User
Access device
Identity of user
Password of user
Physical unclonable function
Biometric generation function
One-way hash function
Symmetric encryption with key
Biometric replication function

Symbols used in the proposed scheme.

3.1 System initialization

Cloud server selects a large prime number , generates a random number and hash function . Then, computes , and publicly discloses the parameters , while keeping as a long-term private key securely stored. Figure 2 is flowchart for proposed scheme.

FIGURE 2

3.2 Registration

3.2.1 Access device registration

sends its identity to Cloud server. The registration process is as follows:

Step 1: Access device choose its identity , selects a challenge value , computes and , and sends the registration information to .

Step 2: Upon receiving , first checks whether is already registered. If it is not registered, cloud server computes , , then sends to and stores , , and in cloud server database.

Step 3: The access device receives the message, saves and the challenge value .

3.2.2 User registration

Step 1: selects identity and , then selects a random number , computes , and sends to cloud server.

Step 2: When receives the message, it first checks if the user’s already exists. If it already exists, meaning user is already registered, end the session. If there is no duplication, cloud server proceeds to the next step. The cloud server generates an anonymous identity , where is the current timestamp, computes , and , stores , , , and in SC. Then sends it to .

Step 3: Upon receiving SC, inputs their biometric features , calculates , then computes , and generates a challenge , calculating . The user then computes , and . Finally, the user stores in their smart card SC, and securely keeps the smart card.

3.3 Login and authentication

At this phase, user and the access device complete authentication and key agreement through the cloud server. The process is illustrated in Figure 3.

FIGURE 3

Step 1: The user inserts the smart card inputs their , login password , and provides biometric information . Then, calculate , compute , and . Next, calculate and . Then, calculate , and check if Afterward, generates two random numbers and Calculate and User sends the message to cloud server .

Step 2: receives the login request from , first checks Then, computes , and The server then verifies if If the equality does not hold, rejects session. If the equality holds, retrieves the database using , obtaining generates and calculates , and Then, calculate and send to the access device

Step 3: Access device receives the message from server Access device checks , then calculates = and Then, and is verified. If the value is correct, access device generates a random number and calculates , and . Access device then sends and to cloud server .

Step 4: Upon receiving and , computes , and verifies the value of . Then, , and . Next, calculate . sends the message to user via a public channel and calculates , sending to access device

Step 5: Upon receiving the message, the user computes and , then verifies whether If it holds, then mutual authentication between and server is successfully completed, and a session key is established.

Step 6: Upon receiving the message, computes and verifies whether . If the equality holds, mutual authentication between and is successfully completed, and a session key is established.

4 Security analysis

In this section, we conduct a security analysis of the proposed scheme under the Random Oracle Model (ROM). Furthermore, additional security properties are examined through semantic evaluation [4547].

4.1 Formal security proof using ROM

The security of session keys can be formally proven through rigorous mathematical analysis of the protocol within the Random Oracle Model (ROM).

Participants: Entities involved in the scheme include the user , cloud server and the access device . Let , , and respectively denote instances of the user , cloud server and access device .

Accepted: Instance enters an accepted state when it receives the final scheme message during communication process. The instance maintains the sequence of all exchanged messages, forming a session identifier for the current session.

Partnering: Instances

and

are regarded as partners when the following criteria are met:

  • Both instances must be in the accepted state.

  • and must have mutually authenticated and share the same session key.

  • and must be each other’s designated partner.

Freshness: Instances and are considered fresh if the adversary has not obtained their session key using the query.

It is assumed that adversary has complete control over the communication in the system. can intercept, eavesdrop and modify messages. In the Random Oracle Model, can perform simulated queries to compromise the authenticity and confidentiality of key agreement and session keys. The types of queries allowed are as follows:

: Simulates a passive attack where obtains all messages exchanged between user , cloud server and the access device .

: Simulates an active attack. impersonates instance and sends message to instance . If is valid, responds appropriately; otherwise, the simulator terminates the query.

: If , the user’s password is revealed. If , the smart card itself is returned. If , biometric data is provided.

: Allows to retrieve all information stored in the device node.

: Allows to obtain session key generated by instance and its partner.

: initiates this challenge query on a legitimate instance of and . fair coin c is tossed to determine the output; If c = 1, the real session key is returned; If c = 0, a random string is returned; In other cases, the output is null. Only A knows the outcome of the coin toss.

Semantic Security: can perform multiple queries on and guess a bit value c. Let denote the authentication and key agreement protocol. If c = c, wins the game and breaks the semantic security of . The event where wins is denoted as Succ. Thus, we have:where , , and respectively denote the number of random oracle queries, the number of Send queries, the output length of random oracle and the probability of a false positive by the simulation extractor. The parameters and are those of the Zipf distribution.

Proof: Five distinct games are defined for formal analysis. Let denote the success event in game , and represent the probability that adversary correctly guesses the value of and wins the game in . initiates the Test query and attempts to guess the value of .

Game :

simulates a real-world attack on the proposed protocol . Adversary must randomly choose a bit ccc before the game begins. By definition, we obtain:

Game :

In this game, within the random oracle model, adversary performs a passive eavesdropping attack. However, based on the messages transmitted over the public channel, is still unable to compute the session key or obtain any other secret information. Therefore, we have:

Game :

Building upon the previous game, additionally includes simulations of the Send and Hash queries. Assuming that attempts to find a collision in the hash function, the collision probability based on the birthday paradox is given by:

Game :

Building upon Game

, Game

introduces the

query to simulate the security of multi-factor authentication. Through this query, adversary

can interact with the user

and

to attempt to obtain the session key. Assume that adversary

can compromise at most two authentication factors. This leads to the following three scenarios:

  • obtains the smart card and the user password: That is, by issuing and , adversary gains access to the smart card and password. In this case, may attempt to retrieve the biometric feature through Send queries. The success probability is: .

  • obtains the password and the biometric : That is, issues and . However, without access to the smart card’s internal data, the probability that successfully impersonates the user is negligible.

  • obtains the smart card and biometric : That is, by issuing and , adversary acquires the smart card and biometric data. In this case, may attempt to recover the password via Send queries. The success probability is:

In addition, due to the use of fuzzy extractors, false positives may occur. The probability that adversary successfully deceives the reproduction function Rep(⋅) is bounded by , and the success rate for such deception through Send queries is: .

Therefore, we obtain the following result:

Game :

In Game , adversary is allowed to perform the query, which simulates the physical capture of a sensor node. Through this query, obtains the information stored in . In addition, can use the Execute query to eavesdrop on all messages exchanged during the authentication and key agreement process. Although adversary attempts to compute the session key, decryption is not possible because lacks the user’s secret paramaters. Furthermore, the adversary cannot obtain the necessary random values used in key generation. As a result, in order to derive the session key, must solve the CMDLP problem. Let denote the advantage of adversary in solving the CMDLP problem within time t. Therefore, we conclude:

In Game , all random oracle simulation queries are executed. Therefore, we have:

According to Equations 612, we obtain: . The above sequence of games demonstrates that the protocol is provably secure under the Random Oracle Model (ROM).

4.2 Semantic analysis

In this section, we discuss the main safety features. We have conducted a comprehensive analysis of the plan to demonstrate that the proposed approach can achieve these safety features [

48

].

  • User Anonymity: During the registration phase, message is transmitted over a secure channel. Therefore, if an attacker attempts to launch an illegal attack, their only option is to perform cryptanalysis using the information intercepted from the user’s smart card (SC) and non-secure channel. Suppose the attacker has stolen the user’s smart card SC and conducted a power analysis attack to extract the parameters stored in the card. Even so, the SC does not contain the user’s identity information. Any attempt to recover the identity would inevitably encounter the difficulty of inverting the hash function. Moreover, even if the attacker intercepts communication over the non-secure channel, the use of anonymous identities by the user prevents the attacker from obtaining the user’s real identity.

  • Replay Attack: Replay attack refers to the scenario where an attacker intercepts a message that has previously been authenticated by , the cloud server, or , and then retransmits it to the cloud server, or in order to deceive them. However, throughout the communication process, fresh timestamps and random numbers are always used to ensure security. The difficulty of the Chebyshev Polynomial-Based Diffie-Hellman Problem () ensures that the attacker cannot alter the message. Therefore, the protocol effectively defends against replay attacks.

  • User Impersonation Attack: Whether it is an unregistered illegal user or a malicious legitimate user, in order to impersonate a legitimate user and complete the subsequent authentication process, the attacker must successfully obtain 's , login password , and input the biometric information . Even if the attacker obtains 's smart card and uses energy analysis attacks to extract the relevant parameters from the card, along with the previously intercepted communication data, the mathematical challenges they face in obtaining the correct , and remain unsolvable based on the current foundation.

  • Session Key Security: Based on the proposed scheme, after mutual authentication and key exchange between the user and the device, a session key for subsequent communication can be negotiated. The session key is given by .

  • Perfect Forward Security: The session key between the user and the device node is denoted as and this key depends on the user and the random number. Suppose an attacker has access to the long-term keys of the protocol participants, but in order to obtain the random numbers associated with the session key, the attacker must solve the difficult Chaos Mapping Computationally Hard Discrete Logarithm Problem (CMDLP). Additionally, the attacker cannot obtain the user’s identity, making it impossible to compute the session key. Therefore, this protocol ensures perfect forward security.

  • Man-in-the-middle attacks: Assume that can eavesdrop on the messages transmitted between the user and the cloud server over a public channel. However, cannot obtain the user’s , password and biometric information . Therefore, even if tampers with the authentication and key exchange request message from user , they will still be unable to authenticate through cloud server. Similarly, does not know the device node’s secret parameter, so they cannot complete the authentication even after tampering with the messages and transmitted over the public channel.

  • Insider Privilege Attack: Insider Privilege Attack refers to a situation where a legitimate system administrator turns into a malicious attacker and exploits their legitimate privileges to access confidential system information. As a result, insider privilege attacks often pose a greater threat than external attacks. In this protocol, once gains cloud server’s privileges, they can access the user’s information and the user’s smart card SC. Then, could use side-channel attacks to extract data stored in the smart card SC. Although attacker may link the anonymous identity with the smart card SC, they cannot guess the user’s password , nor can they compute the biometric value . Therefore, this protocol is resistant to insider privilege attacks.

  • Mutual Authentication: In this protocol, mutual authentication is achieved between the user and the device node through cloud server. Specifically, user and the cloud server perform mutual authentication using verification parameters . Similarly, the cloud server and the device node achieve mutual authentication using verification parameters . Therefore, this protocol enables mutual authentication.

  • Device Node Forgery Attack: Suppose attacker forges a legitimate device node to create message . Attacker generates a random number and attempts to compute and . However, without knowing the secret parameter, attacker cannot generate a legitimate device node’s message. Therefore, this scheme is resistant to device node forgery attacks.

5 Performance analysis

In this subsection, we compare the proposed scheme with other existing scheme.

5.1 Function

In this subsection, the proposed scheme is compared with other existing protocols. The proposed scheme can effectively resist various types of attacks and largely meets the relevant security and functional requirements. In the table, a check mark (√) indicates that the protocol satisfies the corresponding security or functional requirement, while a cross mark (×) indicates that it does not. F1–F10 represent abbreviations for different attack types and functional features, with corresponding explanations provided below Table 2.

TABLE 2

Function[42][43][44][45][46]Our
F1×
F2×
F3
F4
F5×
F6
F7
F8
F9×
F10×

Function comparison.

F1, User Anonymity; F2, Replay Attack; F3, User Impersonation Attack; F4, Session Key Security; F5, Perfect Forward Security; F6, Man-in-the-middle attacks; F7, Insider Privilege Attack; F8, Mutual Authentication; F9, Device Node Forgery Attack; F10, Temporary Secret Disclosure Attack.

5.2 Computation overhead

This subsection presents a comparison of the computational overhead of the proposed schemes. The comparison is based on the computational efforts required by the protocol entities during the authentication and key agreement processes. The computation times are uniformly defined as follows: hash function, elliptic curve scalar multiplication, and chaotic map computation cost are denoted as , and , respectively.

As shown in Table 3 and Figure 4, the proposed scheme exhibits significant advantages in multiple aspects. In terms of total computational cost, the Our scheme has a total of , which is among the lowest compared to other schemes. Although the usage of is slightly higher, the amount of is relatively lower, indicating a well-balanced design between complex and regular computations, thus leading to higher efficiency in resource utilization.

TABLE 3

SchemeUser ()Cloud server ()Access device ()TotalTotal time (ms)
[42]4.07
[43]1.88
[44]5.59
[45]--2.49
[46]1.53
Our1.88

Comparison on computation overhead.

FIGURE 4

Regarding total execution time, the Our scheme achieves a time of 1.88030, which is only slightly higher than that of [46] (1.53252) and [43] (1.87992), but significantly better than other schemes such as [42] (4.07076) and [44] (5.59188). This demonstrates that the Our scheme performs excellently in terms of efficiency and can meet high-performance requirements.

Furthermore, in terms of task distribution, the Our scheme maintains a balanced computational load among the user, cloud server, and access device. Specifically, the user side is responsible for , the cloud server handles , and the access device takes . Compared to other schemes where one component may bear a disproportionate load, the Our scheme avoids performance bottlenecks, contributing to more stable and scalable system operation.

In summary, our scheme demonstrates strong overall advantages in computational efficiency, execution time, and load distribution, making it well-suited for practical deployment and widespread application.

5.3 Communication overhead

Table 4 and Figure 5 present a comparison of the communication overhead between the proposed protocol and five related protocols. For the sake of a fair comparison, the lengths of various parameters are uniformly set as follows: 160 bits for the Chebyshev polynomial, 320 bits for points on the elliptic curve, 160 bits for hash values, 128 bits for random nonces, 32 bits for the identities of the user and the access device node, 32 bits for timestamps, and 128 bits for blocks used in symmetric encryption and decryption. In addition, the communication process in the proposed protocol involves several potential components, including the user terminal, the PUF module embedded in the device, the encryption/decryption unit, the secure communication channel (e.g., TLS/SSL), and the core cloud server with its key management and auditing modules. These components together ensure the reliability, confidentiality, and integrity of message exchanges, forming the foundation for a fair and meaningful comparison of communication overhead.

TABLE 4

SchemeCommunication overhead (bits)
[42]2,848
[43]
[44]
[45]
[46]
Our

Comparison on communication overhead.

FIGURE 5

As shown in Table 4, the proposed scheme demonstrates a significant advantage in terms of communication cost, achieving a total of 2,144 bits, which is relatively low compared to all the referenced schemes.

Specifically, compared to the highest communication cost in [43] (3,232 bits), the proposed scheme reduces the overhead by approximately 33.7%. It also achieves reductions of about 24.7% compared to [42] (2,848 bits), 21.2% compared to [44] (2,720 bits), and 23.9% compared to [46] (2,816 bits). Although [45] has the lowest communication cost (1,760 bits), it likely involves trade-offs in terms of computational complexity, security mechanisms, or functional completeness; otherwise, it would not be outperformed by more efficient schemes.

Overall, the proposed scheme effectively reduces communication overhead while maintaining system security and functional integrity. It achieves a communication cost optimization of approximately 20%–35% compared to most existing schemes, making it well-suited for bandwidth- and energy-constrained environments such as the Internet of Things and edge computing.

6 Conclusion

This paper presents an anonymous and secure authentication scheme for 6G cloud environments by combining Chebyshev chaotic mapping with the PUF mechanism. The scheme achieves secure identity verification, session key confidentiality, and resistance to common network attacks, while experiments demonstrate significant improvements in authentication efficiency and reductions in computational and communication overhead. Limitations remain regarding large-scale scalability, cross-vendor PUF compatibility, and sensitivity of chaotic parameters, which open meaningful directions for future research. Overall, the scheme offers a promising security solution for high-concurrency 6G cloud systems and provides a foundation for further exploration.

Statements

Data availability statement

The original contributions presented in the study are included in the article/supplementary material, further inquiries can be directed to the corresponding author.

Author contributions

SY: Conceptualization, Formal Analysis, Investigation, Project administration, Resources, Validation, Visualization, Writing – original draft. ZJ: Data curation, Methodology, Software, Supervision, Writing – review and editing.

Funding

The author(s) declare that no financial support was received for the research and/or publication of this article.

Conflict of interest

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

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The author(s) declare that no Generative AI was used in the creation of this manuscript.

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Summary

Keywords

6G, efficiency, authentication, anonymous, secure, cloud computing

Citation

Ying S and Jiang Z (2025) Efficient and secure authentication scheme with user anonymity based on cloud computing in 6G. Front. Phys. 13:1647836. doi: 10.3389/fphy.2025.1647836

Received

16 June 2025

Revised

09 October 2025

Accepted

28 October 2025

Published

26 November 2025

Volume

13 - 2025

Edited by

Chengyi Xia, Tianjin Polytechnic University, China

Reviewed by

Devishree Naidu, Shri Ramdeobaba College of Engineering and Management, India

Zhang Zhipeng, Tianjin Polytechnic University, China

Updates

Copyright

*Correspondence: Songpeng Ying,

Disclaimer

All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.

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