Authentication Mechanisms:

When a mobile device establishes a connection and initiates communication over a wireless network, there is no guarantee of the secrecy of user credentials. Thus, optimizing the authentication process within a mobile cloud environment is essential. Tabrizchi et al [1] delve into authentication and identity management issues in MCC, highlighting two main technologies of security, access control, and user authentication. In MCC environments, where users interact with cloud resources through mobile devices over potentially insecure networks, Role-Based Access Control (RBAC) provides a flexible and scalable framework for managing access rights, mitigating risks associated with unauthorized access and data breaches. The RBAC is an access control technique that grants access to the user, based on their roles. User authentication techniques include Public Key Infrastructure (PKI), User ID and Password, Multi-Factor Authentication (MFA), and Single Sign (SSO).

A variety of authentication techniques serve as the backbone of the MCC framework, ensuring the authenticity of users. For instance, Fregly et al [23] present the Merkle Tree Ladder (MTL) mode, designed to reduce signature size impact in practical scenarios, especially within Mobile Cloud Computing (MCC) contexts. MTL mode condenses signatures, enabling their transmission in fewer bits between signers and verifiers. Through shorter condensed signatures and occasional longer reference values, MTL mode streamlines authentication processes while maintaining cryptographic resilience. The mode's effectiveness in reducing signature size impact, even with evolving cryptographic algorithms, underscores its potential for widespread adoption in MCC and other applications. Additionally, the author emphasizes the need for further specification development and integration considerations to fully leverage MTL mode's benefits across various authentication mechanisms. Overall, MTL mode offers a promising solution to optimize authentication efficiency and security in MCC environments and beyond

Likewise, ensuring confidentiality in the MCC environment relies on effective encryption measures [12][22]. Cao et al. [24] highlight the critical role of encryption in mobile computing, emphasizing its importance in safeguarding sensitive data during transmission and processing on mobile devices. In edge computing scenarios, where data processing occurs locally before transmission, encryption ensures confidentiality and mitigates the risk of unauthorized access. By employing encryption techniques, mobile computing environments can protect sensitive information from interception and maintain the security of mobile applications and services. Moreover, encryption secures communications between mobile devices and edge nodes, enhancing data privacy and overall security in mobile computing environments [14][17]. Overall, encryption plays a vital role in maintaining confidentiality and safeguarding sensitive data in the dynamic landscape of mobile computing [10].

Smart devices use MCC to do more things by sending some tasks to big computers on the internet. Ferrag et al. [22] conducted a comprehensive review of authentication schemes for smart mobile devices, categorizing threat models into five types and countermeasures into four categories. It analyses cryptographic functions, personal identification methods, and security analysis techniques used in these schemes. The surveyed schemes encompass biometric-based, channel-based, factor-based, and ID-based authentication. A comparative analysis is performed that, covers performance, limitations, and computational complexity. Identified challenging research areas include false data injection attacks, analysis of smart mobile devices under topology attacks, group authentication, and key agreement security in 5G networks.

Moreover, AlAhmad et al. [3] highlight critical security issues in Mobile Cloud Computing (MCC), particularly concerning authentication, privacy, and trust. It identifies shortcomings in existing MCC models, especially regarding cloud-to-client authentication. Despite numerous studies on MCC, security concerns remain inadequately addressed, posing risks to data security, privacy, and integrity. The findings underscore the necessity for comprehensive MCC models that address all security threats, including authentication challenges, to ensure robust protection of data and communication channels. Future research should prioritize developing holistic MCC models that integrate advanced authentication mechanisms and privacy-preserving techniques. Industry stakeholders must prioritize security in MCC implementations to mitigate potential threats and safeguard user privacy and data integrity effectively.

Similarly, Papaioannou et al. [25] keystroke-based authentication is incorporated as a means to enhance security during human-mobile interactions. This authentication method captures the unique typing patterns of smartphone users, adding a layer of security. By analyzing keystroke dynamics, such as typing speed and rhythm, the system can verify the identity of the user. The dataset includes data from various sensors, including the accelerometer, gyroscope, and microphone, to gather comprehensive information about user interactions. Keystroke-based authentication offers a seamless and non-intrusive way to verify user identity while ensuring usability and convenience. This approach contributes to the development of secure authentication mechanisms for mobile devices used in border control scenarios.

Furthermore, the authors analyze several possible authentication attacks, including eavesdropping, Man-in-the-Middle (MITM), replay attacks, session hijacking, Verifier impersonation, and non-repudiation. These attacks pose significant threats to the security of cloud-based systems and can lead to unauthorized access, data breaches, and identity theft. To mitigate these risks, the authors of this study proposed prevention mechanisms outlined in Table 1. These prevention mechanisms likely include a combination of encryption protocols [12], authentication methods, access control measures, and intrusion detection systems [7] designed to detect and thwart potential attacks in cloud environments. Implementing these prevention mechanisms is crucial for safeguarding sensitive data and ensuring the integrity and security of cloud-based services.

Table 1: Possible attacks on Authentication mechanisms

Analysis of Authentication Mechanisms in MCC:

In this section, we have systematically mapped out various authentication schemes discussed in the literature survey according to the evaluation criteria set by the National Institute of Standards and Technology (NIST) [27][28][29][30][31]. In our analysis, we have thoroughly examined a diverse range of authentication techniques employed between mobile terminals and cloud service providers, leveraging the framework provided by the National Institute of Standards and Technology (NIST). This evaluation has enabled us to identify the NIST levels at which these authentication mechanisms operate within the Mobile Cloud Computing (MCC) paradigm. NIST (National Institute of Science and Technology) is a non-regulatory federal agency of the U.S. that plays a crucial role in addressing issues of science and technology.

We have evaluated different authentication mechanisms in the domain of MCC as shown in Table 2, based on the levels of NIST [29]. The protocols meeting the requirements of level 1 include challenge-response protocol and SSO. Simple password challenge-response protocol is evaluated at this level and it combines a password with a challenge to generate an authentication reply. Kerberos, a single sign-on authentication system, validates the principal identities by generating tickets for each service requested by the client. Each ticket has different components: server, client, address, timestamp, lifetime, key (CIS), and key(s). The verifier may obtain a subscriber password from the Cloud Service Provider (CSP) and authenticate the claimant using the challenge-response protocol. This level of authentication aims to prevent replay and online guessing attacks effectively.

In our evaluation, we have determined that single-factor authentication and the Kerberos protocol meet the requirements of level 2 according to the NIST framework. CSP provides a secure mechanism that enables the verifiers to validate the credentials provided by claimants. The verifier authenticates the claimant using a password through a secure encrypted channel, often established through tunneling. This channel effectively safeguards against replay attacks, one-line guessing, and eavesdropping but it remains vulnerable to man-in-the-middle attacks.

The protocols that meet the requirement at level 3 include multi-factor authentication and a one-time password system, bolstered by cryptographic techniques, and meet the stipulated requirements. The cryptographic token is a physical hardware device designed to enhance security in authentication processes. The cryptographic token is used to combine the nonce with a cryptographic key to produce an output that is sent to the verifier as a password. This password is cryptographically generated once. Level 4 provides the highest level of authentication as well as assurance in the practical remote network.

Table 2: Authentication mechanisms

The authentication techniques are mentioned below in Table 2 along with a description, NIST level, security features, and security challenges. Each authentication technique was analyzed based on its cryptographic functions, which align with the levels defined by the National Institute of Standards and Technology (NIST). Later, in security features, we analyzed the confidentiality, integrity, availability, authentication, and non-repudiation parameters that are covered by different authentication mechanisms. Each authentication mechanisms have different levels from Level 4 to Level 1 and we have analyzed them based on different attacks that have been launched in this mechanism.

Authentication Levels of NIST:

The FIPS 140 Publication Series, issued by NIST, serves as a comprehensive guideline for establishing requirements and standards concerning both hardware and software cryptographic modules [29]. Within this series, FIPS 140-2 delineates four distinct levels of security, denoted from "Level 1" to "Level 4". At Level 1, there exists minimal assurance in asserted identity, where identity proofing may be optional, particularly in cases prioritizing user anonymity. While plaintext passwords cannot be shared over a network, a basic password challenge-response protocol suffices. However, this level remains vulnerable to eavesdropping attacks due to the lack of encryption [29]. Moving up to Level 2, a significantly enhanced security mechanism is implemented, incorporating cryptographic functions for encryption to safeguard against eavesdropping attacks. Additionally, a long-term shared authentication feature is exclusively disclosed to the subscriber and the Cloud Service Provider (CSP). Level 3 introduces a multi-factor remote authentication mechanism, offering users the flexibility to utilize biometric functions or passwords to activate the key and gain system access. Authentication hinges on providing proof of possession of a key or password using a cryptographic protocol. Finally, Level 4, tailored for transactions necessitating the highest confidence in asserted identity accuracy, shares security features with Level 3. Moreover, Level 4 integrates a "hardware cryptographic module" stored within hardware devices. Authentication mandates the claimant to validate control over the token through a secure authentication protocol. Strong cryptographic functions are mandated for all sensitive data transfers, although symmetric key technology may also be employed [29]. The available authentication frameworks focus on different aspects of security, there is always room for improvement. According to NIST evaluation criteria, the level 3 and level 4 authentication mechanisms are considered better approaches for authentication as compared to level 1 and level 2. However, achieving a balance between security and performance remains a challenge, as there is no single technique that fully addresses both aspects without compromising the other. Moreover, resource limitations hinder the implementation of security algorithms used in cloud computing on mobile devices. There is a need for a lightweight secure framework that provides security with minimum communication and processing overhead for mobile devices. Machine learning plays an active role in different fields of life and the integration of machine learning algorithms holds promising results to enhance authentication methods across various fields [4][7][33][30][31][34][35][21][36][37][38] [39][40][41][42][43][44][45][46][47][48][48][49][50][51] [52][53].

Navigating Security and Privacy Challenges in MCC:

The integration of emerging technologies such as the Internet of Things (IoT) and Artificial Intelligence (AI) presents both promising prospects and formidable challenges concerning security and privacy within the realm of MCC [7][33]. IoT devices, renowned for their pervasive connectivity and data aggregation capabilities, significantly augment the data flow to and processing within the cloud, thereby eliciting apprehensions regarding the confidentiality and integrity of data [12][8][16][6][17][18]. Furthermore, the deployment of AI-driven analytics systems in MCC environments may inadvertently expose sensitive information to potential breaches or unauthorized access. As these technologies advance and become more ubiquitous within MCC ecosystems, proactive measures are imperative to mitigate security vulnerabilities and uphold user privacy. Additionally, while MCC has garnered attention as a cost-effective solution for entrepreneurs and businesses, leveraging third-party services for mobile applications, it concurrently poses significant challenges and threats due to the relinquishment of data control to external entities.

Tabrizchi et al. [1] discussed that MCC networks leverage cloud resources to enhance mobile device capabilities, yet the integration of cloud and mobile introduces security risks due to data transmission over potentially insecure networks. MCC networks and robust authentication mechanisms play a significant role in triggering non-repudiation. By ensuring that users are accurately identified and their actions are securely authenticated, MCC systems can establish a strong foundation for non-repudiation. When users access cloud resources through MCC networks, Multi-Factor Authentication (MFA) and other security measures ensure the identity of the user performing actions [16]. This authentication process generates digital signatures or other forms of cryptographic evidence that tie specific actions to authenticated users. Consequently, in the event of disputes or claims, these digital signatures serve as irrefutable proof of user actions, preventing users from denying their involvement and enhancing non-repudiation in MCC environments.

The general challenges encountered by MCC encompass the establishment of a mobile cloud architecture compatible with heterogeneous wireless networks. Unlike traditional setups, there is no single access platform accommodating all operating systems of mobile devices, and connectivity cannot be guaranteed across all devices. Most people use mobile devices for calls and internet access, and the open accessibility of resources during internet usage exposes users to various threats [3]. However, multiple users who are unaware of the challenges, fail to adequately protect their mobile devices and often store sensitive credentials on their mobile phones without considering potential theft.

In MCC, data accessibility extends beyond the confines of home and office, allowing users to easily access and manage data from anywhere via the cloud. This transition essentially transforms data storage from static locations to a mobile, pocket-sized format. Although prospects of MCC are promising, however, certain threats and limitations persist, including poor connectivity with the internet, bandwidth capacity, mobility management issues [11], and storage space in the mobile device [6][19]. These issues can be resolved by customizing service software deployed on a nearby cloudlet, which are small instance of the cloud. Cloud and mobile device resources should be balanced so they can easily communicate with each other. It is imperative to maintain a balance between cloud and mobile device resources to ensure seamless communication and functionality.

In the domain of MCC, several threats persist including consistency, limited scalability, and portability, primarily due to insufficient security measures and the absence of open standards. The aforementioned threats hinder the rapid expansion of MCC subscribers. The higher authority members of an organization including IT executives and CEOs, express reluctance to adopt cloud services due to concerns regarding security risks, trust issues, and privacy considerations. Cloud service providers have to mark all the security issues to provide a completely secure environment to attract potential customers. Moreover, many areas within MCC, such as intrusion detection and prevention systems, and security and privacy of user’s data stored on the cloud server, require further attention and development [12].

Mobile and cloud computing encounter emerging challenges related to confidentiality [20], integrity, authentication, and many of which are rooted in the baseline of virtualization technologies. The use of third-party services in MCC introduces risks related to loss of control over physical infrastructure and shared resource vulnerabilities, impacting security and privacy. Trust in providers' ability to isolate virtual machines and implement robust security measures is crucial to mitigate breaches and uphold data integrity in MCC environments. While, utilizing third-party services, users lack the control over physical hardware infrastructure of the cloud, leading to security threats arising from multiple virtual machines coexisting on a particular physical machine. Trust in cloud service providers is crucial, particularly regarding their ability to properly isolate virtual machines [7]. Since MCC is built upon the cloud computing infrastructure, it inherits and must address challenges faced by cloud computing.

Similarly, many threats are related to identity management and credential theft that lead to security problems [33]. Managing identities and controlling access is a challenging task for cloud providers, particularly as they remotely validate the identity of the user. This challenge is exacerbated when mobile phones are stolen or accessed by unauthorized individuals, and credentials or passwords are stored improperly on the device, leading to potential security breaches.

Practical Implication:

The practical implication of the study on Mobile Cloud Computing (MCC) security is significant for several reasons:

Enhanced Security:

By addressing security vulnerabilities in MCC, the study contributes to enhancing the overall security of mobile cloud environments. This is crucial for ensuring the integrity and confidentiality of data processed and stored in MCC systems.

Improved Authentication Mechanisms:

The study highlights the importance of robust authentication protocols in mitigating security risks in MCC. By analyzing various authentication mechanisms, the study offers insights into effective strategies for enhancing security in mobile cloud environments.

Data Protection:

The innovative solutions proposed in the study aim to safeguard sensitive information in mobile cloud environments. This is essential for protecting user data from unauthorized access and ensuring data privacy.

Cyber Threat Resilience:

The study emphasizes the need for continual research and development efforts to bolster security measures within MCC. This is crucial for ensuring the resilience of mobile cloud environments against evolving cyber threats.

Discussion:

The findings of our evaluation indicate that authentication mechanisms in MCC vary in their alignment with NIST levels and their effectiveness in addressing security concerns. Mechanisms such as multi-factor authentication and one-time password systems, which leverage cryptographic techniques, demonstrate greater resilience against a wider range of attacks and are associated with higher NIST levels. However, we observed challenges in achieving a balance between security and performance across different authentication approaches. While some mechanisms excel in providing robust security, they may introduce higher processing overheads or resource requirements, posing challenges for implementation on mobile devices. Additionally, the integration of machine learning holds promise for enhancing authentication methods in MCC, offering opportunities for future research and development in this area. Overall, our analysis underscores the importance of selecting authentication mechanisms that align with the specific security needs and resource constraints of MCC environments, while also highlighting the need for ongoing innovation to address evolving security threats.

Reference