Financial management is the core link of enterprise operation in today’s digital age. Its security and efficiency are directly related to the survival and development of the enterprise [1]. With the rapid advancement of technologies such as cloud computing and the Internet of Things (IoT), enterprise financial management systems are gradually transitioning from traditional single-machine or LAN models to multi-server, cross-regional, and high-concurrency network environments [2]. This transformation not only greatly enhances the flexibility and real-time performance of financial management but also poses unprecedented challenges to the security of the system. The accompanying network information security issues constantly threaten the privacy and security of information in our communication process [3]. The identity authentication key protocol designed based on cryptography can enable users to securely enjoy the convenience brought by network services and effectively ensure network information security [4].

With the expansion of enterprise scale and the globalization of business, financial management systems become increasingly complex. The amount of data that needs to be processed has exploded, with extremely high requirements for real-time, accurate, and secure data [5]. To address these challenges, enterprises adopt multi-server architectures and improve system stability and reliability through technologies such as load balancing, data redundancy, and disaster recovery backup. However, while a multi-server environment brings convenience, it also exacerbates the difficulty of security management [6]. The financial management network in a multi-server environment faces complex and ever-changing network threats, including but not limited to data breaches, illegal access, service interruptions, and advanced persistent threats [7]. Once these risks become a reality, they cause incalculable economic losses and reputational damage to the enterprise.

Traditional static security strategies are no longer effective in dealing with increasingly complex and ever-changing network attack methods [8]. Therefore, developing a financial management network security protocol that can adapt to environmental changes and intelligently identify and defend against potential threats has become the key to ensuring the security of enterprise assets and promoting sustainable business development. Traditional security protocols are designed for a single server [9]. When a user needs to request network services, providing authentication factors such as identity and password to the single server can obtain the service requested by the server. Due to the rapid development of the network, there are a large number of servers in the current Internet environment [10]. When users want to request services, they need to register with all the requested single servers. Then, users need to remember all the authentication factors, such as identity and password verification, when registering. This is obviously a huge resource burden for users, and there are extensive illegal attacks on the public channel of communication between users and servers [11]. It is very likely that a set of user identity or authentication factors are disclosed and attacked, thus affecting the security of other systems. This is undoubtedly a huge security risk. The factors that must be considered when designing security protocols for different multi-server network environments are also different [12, 13]. Therefore, in the design process of security protocol in a multi-server environment, it is not only necessary to meet the security requirements of the application environment but also to balance computational and communication costs to achieve better performance.

Especially driven by the current global wave of informatization, as the core support for enterprise operations, enterprise financial management systems are undergoing unprecedented changes and challenges. With the expansion of enterprise scale and the globalization of business, traditional financial management models are no longer able to meet the high requirements of modern enterprises for data processing speed, system stability, and information security [14]. In a multi-server environment, financial management systems not only need to handle massive amounts of financial data but must also ensure the security and integrity of these data during cross-regional and cross-network transmission [15]. An adaptive security protocol can automatically adjust security policies according to changes in the network environment to effectively resist various network attacks. It ensures the security and integrity of financial data. At the same time, the protocol can optimize system performance and enhance user experience while ensuring security. Our main contributions are summarized as follows.

(1) Considering the requirements of financial management networks in multi-server network environments, we propose a lightweight adaptive security protocol. In this protocol, both communication parties need to register at the control server and then engage in security negotiations. Through a hash function, this protocol can negotiate session keys with lower computational and communication costs. This protects the transmission of confidential messages and enhances communication security.

The other parts of the article are described. Section Ⅱ and Section Ⅲ systematically review the current research status in related fields. Section Ⅳ comprehensively introduces the design ideas, specific implementation steps, and key technical details of the security protocol. Section Ⅴ and Section Ⅵ, respectively, focus on the security verification and performance analysis of the protocol. Finally, Section Ⅶ is the summary.

With the significant advancement of communication technology, ensuring the confidentiality and privacy of user information has become particularly important. Therefore, there have been many studies on multi-server authentication protocols both domestically and internationally.

Lamport [16] first proposed a password-based remote identity authentication scheme, which was based on a verification table and password. Subsequently, researchers proposed an increasing number of authentication schemes, but most of them were suitable for single-server environments. However, due to the increasing demand for security, relying solely on verification tables could not guarantee communication security. In a single-server architecture, when users needed to request services from different servers, remembering the identity and password when logging into each server was challenging. To solve the problem of users needing to remember manage multiple physical passwords and multiple high entropy passwords, an increasing number of identity authentication schemes that could be applied to multi-server environments were proposed. Tsaur et al. [17] introduced the concept of a multi-service model and built an authentication mechanism in a multi-server environment based on the RSA public key cryptosystem and Lagrange interpolation inequality principle. Subsequently, Li et al. [18] integrated neural network technology into a multi-server authentication architecture. Chang et al. [19] proposed a remote authentication scheme that did not require verification table maintenance, and users did not need to remember multi-server passwords, significantly improving the user experience. Yoon et al. [20] used elliptic curve public key encryption technology and designed a three-factor authentication scheme aimed at enhancing security in multi-server environments. However, subsequent research [21] pointed out that this scheme had shortcomings in resisting internal attacks, smart card theft, offline password cracking, and impersonation attacks. In response, Kalra et al. [22] proposed an efficient and cost-optimized multi-server authentication protocol that utilized smart card bidirectional authentication and elliptic curve cryptography technology to achieve higher security. Guo et al. [23] also designed a smart card-based authentication scheme in multi-server architecture, which clearly defined the roles of the registration server, service server, and user. Both users and application servers needed to perform registration once on the registration server. Three-party authentication mode was implemented using the ElGamal public key cryptosystem. Subsequently, the Burrows Abadi Needham logic provided formal proof of the proposed scheme.

Gupta et al. [24] proposed a key exchange authentication scheme that combines biometric cryptography and smart card technology in a distributed multi-client server architecture, particularly for scenarios with multiple registration centers. Subsequently, Li et al. [25] conducted an in-depth analysis of biometric-based identity verification and key negotiation schemes in multi-server environments. They proposed corresponding improvement strategies based on this to further enhance the security and efficiency of the authentication mechanism. Wang et al. [26] reviewed several authentication schemes applicable to multi-server architectures this year and pointed out the security vulnerabilities of the corresponding schemes, proving that the schemes were ineffective in practical applications. Pelaez et al. [27] proposed an enhanced lightweight cloud computing authentication scheme for IoT, which also included a substage called connection attempt evidence. It provided evidence about user and service participation. Unfortunately, the study by Yu et al. [28] revealed significant shortcomings in the security of [27], pointing out that it could not effectively resist impersonation attacks, session key leakage, and replay attacks. They also proposed a secure and lightweight three-factor authentication scheme specifically designed for IoT in cloud computing environments. This scheme innovatively incorporated secret parameters and biometric authentication elements to ensure enhanced mutual authentication mechanisms and user anonymity, effectively addressing various security threats.

Wong et al. [29] focused on the application of 5G wireless sensor networks in electronic health systems and designed a three-factor fast authentication scheme that balances time constraints and user anonymity. This authentication scheme combined a three-factor authentication scheme of biometric, password, and smart card methods to ensure a highly secure communication environment supported by sensors. It maintained user anonymity during the communication process. Tsai et al. [30] proposed a multi-server authentication scheme for online banking transaction environments that used a hash-based multi-server authentication scheme combined with smart cards to authenticate online banking customers and transactions. It provided powerful security features and lower maintenance costs for the online banking platforms of financial institutions. The solution supported interface connection with the banking system, making it easy to integrate the solution into existing banking systems. Sudhakar et al. [31] proposed a multi-server environment-enhanced authentication scheme based on passwords and smart cards by improving the security flaws of [32]. The improved scheme formally proved the security authentication of the scheme using BAN logic and simulated various attacks through Internet security protocol and automatic verification of application tools. The results showed that the improved scheme had better security and performance.

In their research on ensuring authentication security in multi-server environments, Xia et al. [33] introduced the principle of elliptic curve cryptography and designed a three-factor authentication key agreement scheme, significantly enhancing the security of the system. Akram et al. [34] proposed an efficient anonymous authentication key protocol for multi-server infrastructure within the same year. This protocol effectively resisted various security challenges, including impersonation attacks, insider attacks, and password modification attacks. Finally, a formal security analysis of the proposed solution was conducted using a random oracle model. Analysis and comparison showed that this scheme was highly effective for anonymous authentication and key schemes. Wu et al. [35] pointed out the shortcomings of the protocol [36] in terms of fully forward secrecy protection and susceptibility to privileged internal attacks. In response to these security vulnerabilities, they designed a customized authentication key exchange scheme for 5G network multi-server architecture.

Km et al. [37] focused on improving security in multimedia IoT environments and proposed an enhanced multi-factor authentication scheme with provable security. Hsu et al. [38] developed an end-to-end cryptographic authentication key exchange scheme for multi-server architecture in edge computing networks. This scheme allowed end users to use easy-to-remember passwords for initial login and then used external agents to calculate shared keys to achieve secure communication with specific service end users. It was particularly worth mentioning that this scheme provided a high degree of user anonymity protection during the communication process.

This article delves into the security and efficiency challenges faced by enterprise financial management networks in the digital age, particularly in the rapid development of technologies such as cloud computing and IoT. The inevitable trend for financial management systems to transition from single-machine or local area network models to multi-server, cross-regional, and high-concurrency network environments is highlighted. Although this transformation significantly improves the flexibility and real-time performance of financial management, it also makes system security issues increasingly prominent. This becomes a key consideration for the sustainable development and survival of enterprises. The issue of network information security, especially data privacy and communication security, has become an important issue that urgently needs to be addressed. We propose a lightweight, adaptive security protocol for special requirements in multi-server environments. This protocol effectively enhances the identity authentication strength and session key security of both communication parties, reducing the risk of data leakage and illegal access. This article comprehensively evaluates the security of the protocol using both informal and formal analysis, ensuring its robustness in various attack scenarios. In addition, we also fully consider the practicality and performance optimization issues of this protocol. By designing with low computational and communication costs, as well as a lightweight message transmission mechanism, this protocol demonstrates good efficiency and user experience in practical applications.