The Internet of Things (IoT) constitutes a sophisticated network that interconnects devices, optimizing functionality across various domains of human activity. Recent literature projections anticipate a significant increase, with estimates exceeding 50 billion connected devices by 2025. Despite its transformative potential, the IoT landscape confronts formidable privacy and security challenges, encompassing intricate issues such as data acquisition, anonymization, retention, sharing practices, and behavioural profiling. Effectively addressing these challenges mandates the development of scalable solutions, innovative management strategies, and adaptable policy frameworks. In this paper, we conduct an exhaustive examination of major IoT applications, alongside associated privacy and security concerns. We systematically categorize prevalent privacy, security, and interoperability issues within the context of the IoT layered architecture. The review highlights current research initiatives focused on developing energy-efficient devices, optimizing microprocessors, and fostering interdisciplinary collaborations to address the challenges in the IoT landscape. To efficaciously manage risks in this dynamic landscape, stakeholders must implement comprehensive strategies that span stringent data protection legislation, extensive user education initiatives, and the deployment of robust authorization and authentication frameworks. This paper aims to empower industry leaders, policymakers, and researchers by providing actionable solutions, not just insights, to navigate the complexities of the IoT landscape effectively. Future research initiatives should prioritize the fortification of security measures for large-scale IoT deployments, the formulation of user-centric privacy solutions, and the standardization of interoperability protocols. By establishing a robust foundational framework, our paper endeavours to spearhead the discourse on IoT applications, privacy paradigms, and security frameworks, paving the way towards a resilient and interconnected future.

1. Introduction

The Internet of Things (IoT) is a revolutionary idea that refers to a vast network of interconnected physical devices, vehicles, appliances, and various objects that are embedded with sensors, software, and other technologies that allow them to collect and exchange data via the Internet or other communication networks. These devices can be everyday objects like smartphones, wearable fitness trackers, home appliances, industrial machines, and even vehicles [1]. The key components of IoT are the embedded sensors and actuators that allow these devices to sense and interact with their environment. These sensors gather data from the surroundings, such as temperature, humidity, motion, and so on. The collected data is then processed by the device’s software, which can make real-time decisions or send the data to a centralized server or cloud for further analysis and storage.

The main goal of IoT is to create a seamless and intelligent network where physical objects can communicate with each other and with humans, leading to more efficient and automated processes, improved decision-making, and an enhanced user experience [2]. By leveraging IoT, businesses and industries can optimise their operations, enhance productivity, and develop new innovative services and products [3]. However, with the increasing adoption of IoT, concerns regarding data privacy, security, and standardization have also emerged [4, 5]. As billions of devices get connected [6], it becomes crucial to ensure robust privacy and security measures are in place to protect sensitive information and prevent potential cyber-attacks. The IoT has the potential to revolutionize various aspects of our lives, bringing forth a new era of interconnectedness and technological advancements. As technology continues to evolve, IoT is expected to play a central role in shaping the future of industry, infrastructure, and everyday living. We outline the following contributions in our paper:(i)This paper provides a comprehensive review covering IoT applications, security issues, privacy concerns, and solutions across various domains.(ii)We highlight the primary applications of IoT and associated privacy and security concerns within the IoT domain, along with proposed countermeasures found in existing literature.(iii)We propose a threat taxonomy for IoT applications, privacy, and security.(iv)Finally, we discuss open research directions relevant to the areas highlighted in this survey.

The rest of the paper is structured as follows. In Section 2, we introduce the multifaceted applications of IoT. In Section 3, highlights IoT security challenges, Section 4, highlights IoT privacy concerns, Section 5, proffers IoT security solutions and IoT interoperability. Finally, Section 6 summarises the research findings and concludes with a discussion on future trends.

2. IoT Applications

In recent years, a few surveys have been conducted to highlight research advancements across various domains. In the following subsections, we categorize existing survey works based on IoT-related objectives. In the following subsections, we categorize the existing survey works on the basis of IoT-related objectives. The way we connect to the world around us is being completely transformed by the Internet of Things (IoT). IoT applications are transforming businesses, improving our lives by connecting everyday objects to the Internet, and enabling them to interact [7].

The IoT is fostering innovation across every sector, from smart homes that provide convenience and energy efficiency to industrial settings that optimise operations through predictive maintenance [8]. The application of IoT for remote patient monitoring helps the medical field, and precision farming increases crop yields in agriculture [9]. Public safety is improved as traffic management becomes more effective in smart cities [10]. The potential of the Internet of Things is limitless as it develops, holding up the promise of a day when connection and data-driven insights will redefine what is possible in our increasingly networked world [11]. Based on the literature synthesis, Figure 1 and Table 1 provide a detailed summary of the multifaceted applications of IoT.

2.1. Smart Healthcare

Smart healthcare is a game-changing method that uses cutting-edge technologies to improve the quality, efficiency, and accessibility of healthcare services [18]. It includes a wide range of applications aimed at improving patient care, streamlining healthcare processes, and empowering individuals to take control of their health [19]. Smart healthcare is changing the face of healthcare by improving patient experiences, lowering costs, and eventually leading to improved health outcomes for individuals and communities [20, 21]. It provides the potential for a future healthcare system that is more efficient and effective. Table 2 outlines recent research areas and major visions in IoT applications for smart healthcare.

2.2. Smart Transportation

Smart transportation uses innovative technologies and data-driven solutions to improve transportation systems’ efficiency, safety, and sustainability [28]. It comprises a wide range of applications aimed at improving mobility, reducing congestion, and reducing environmental impact. Smart mobility is transforming how people and products move, providing answers to urban congestion, environmental concerns, and inefficiencies in transit. It has the potential to make future transit systems more sustainable, accessible, and safe [29]. Table 3 provides a summary of the applications of IoT in the domain of smart transportation and logistics.

2.3. Smart Agriculture

Smart agriculture, also known as precision agriculture, uses modern technology and data-driven solutions to optimise farming, practises, boost agricultural output, and encourage sustainable resource management [36]. Smart agriculture is revolutionising traditional agricultural practises by leveraging the power of technology and data analytics. It has the potential to enhance food output, minimise waste, and encourage environmental stewardship while assuring agricultural sustainability for future generations. Table 4 summarises the applications of IoT as applied in the domain of smart agriculture.

2.4. Smart Military

Smart military, also known as contemporary warfare or defence technology, is the integration of new technologies to improve the capabilities, effectiveness, and efficiency of armed forces. These technologies are intended to strengthen national security, safeguard soldiers, and give a strategic edge in a variety of operational areas [43]. Smart military technologies continue to advance, affecting the future of battle and defence. While these breakthroughs bring considerable benefits, ethical issues and international rules are critical to ensuring responsible and accountable usage in military operations. Table 5 summarises the applications of IoT as applied in the domain of smart military.

2.5. Smart Homes

Smart homes use technology to improve their occupants’ comfort, security, energy efficiency, and general level of living [50]. These developments strive to make daily chores easier and to provide consumers more control over many aspects of their living surroundings. Residents of smart homes enjoy greater control, energy savings, security, and convenience. Table 6 outlines IoT applications in the context of smart homes.

2.6. Smart Industrial Automation

The integration of modern technology to improve manufacturing and industrial processes is referred to as smart industrial automation, often known as Industry 4.0 or the Industrial Internet of Things (IIoT) [57]. In a variety of industrial areas, these technologies increase efficiency, productivity, safety, and sustainability. Manufacturing and industrial processes are being transformed by smart industrial automation, which makes them more efficient, versatile, and sensitive to changing needs [58]. It is vital to the advancement of contemporary manufacturing and industrial enterprises. Table 7 summarises the applications of IoT as applied in the domain of smart industrial automation.

2.7. Smart Environment

Smart environments are physical locations that have been improved with various technologies in order to increase efficiency, sustainability, safety, and the overall quality of life [65]. These smart environment applications have the ability to improve several parts of our life. These smart environment applications highlight how technology may be used to create more efficient, sustainable, and convenient living and working environments in a variety of disciplines. Table 8 summarises the applications of IoT as applied in the domain of smart environment.

2.8. Surveillance

Smart surveillance is the application of new technologies such as artificial intelligence (AI), machine learning, and the Internet of Things (IoT) to improve traditional surveillance systems [72]. These technologies have a wide range of applications in security, safety, and monitoring [73]. Smart surveillance applications are constantly expanding as a result of breakthroughs in AI and IoT technology. While they provide several benefits in terms of security and safety, there are also worries regarding privacy and ethical consequences [7476]. Table 9 summarises the applications of IoT as applied in the domain of surveillance.

2.9. Customer Asset Tracking

Customer asset tracking, also known as customer equipment tracking, is the monitoring and management of assets or equipment held by a company but under the control of customers or clients. This is especially effective in increasing customer service efficiency and asset utilization in a variety of sectors [8183]. Effective customer asset monitoring may help to streamline processes, decrease losses, improve customer happiness, and ultimately save money [84]. It is frequently accomplished by utilising technologies such as RFID (Radio-Frequency Identification), barcoding, GPS tracking, and asset management software. Table 10 summarises the applications of IoT as applied in the domain of customer asset tracking.

3. IoT Security Challenges

The rapid proliferation of Internet of Things (IoT) devices has brought numerous benefits, but it has also introduced significant security risks and vulnerabilities. Several studies and reports have highlighted the potential challenges associated with IoT security [9092]. Figure 2 summarises the security challenges in IoT ecosystem.

According to Sikder one of the most major concerns about Internet of Things (IoT) devices is the threat of unauthorized access [93]. In addition, to Meneghello et al., if adversaries successfully infiltrate these devices, they will be able to exploit security flaws, perhaps exfiltrating sensitive data or coordinating device subversion [94]. Table 11 highlights the widespread security flaws intrinsic to the IoT ecosystem.

These vulnerabilities underscore the pressing need for a comprehensive and proactive approach to securing IoT ecosystems, encompassing robust authentication, encryption, firmware maintenance, interface security, patch management, credential management, physical protection, user education, and privacy preservation. Addressing these issues is paramount in mitigating the ever-evolving threats that IoT devices face. With the emergence of AI and the benefits it offers, it is susceptible to numerous challenges. Current AI security challenges include adversarial attacks, privacy concerns, bias, model security vulnerabilities, reliability issues, explainability gaps, data poisoning, and scalability challenges. Interdisciplinary efforts are needed to enhance robustness, transparency, and regulatory compliance while mitigating risks to privacy, fairness, and intellectual property. We have synthesized the literature and proposed a threat taxonomy for IoT applications, privacy, and security in Table 12.

4. Privacy Concerns in IoT

The massive amount of data collected by IoT devices raises significant privacy concerns as it involves the gathering of personal information, behavioural patterns, and sensitive data from individuals. Figure 3 shows some of the key privacy issues and challenges associated with IoT data collection:

Privacy problems in IoT are intertwined with a web of authorization issues, anonymization quandaries, data retention complexity, data sharing quandaries, and profiling paradoxes [105]. As we navigate through this perilous terrain, it becomes clear that privacy is more than just a legislative concern; it is inextricably linked to the underlying fabric of IoT functioning. To address these challenges, a multifaceted solution incorporating technology, legislation, user education, authorization, and security frameworks is required. Drawing from the literature provided, we propose privacy and security challenges for each IoT layer in Table 13.

5. IoT Security Solutions

Existing security measures and protocols for protecting IoT devices and networks have evolved to address the unique challenges posed by the wide-scale deployment of IoT devices [106108]. Figure 4 summaries the proposed IoT solutions.

According to the literature, IoT privacy and security solutions are being suggested from a range of viewpoints, including unique concepts and technologies [109, 110]. They use a first-principle approach to redefine network security for IoT in their study [111]. They address three primary concerns:(i)The need for scalable alternatives to traditional perimeter defence, as IoT networks necessitate more adaptive security procedures.(ii)They propose new ways for managing security inside deployed IoT networks, recognising the unique problems of safeguarding a large number of linked devices.(iii)They suggest new security policies that provide the essential generality to regulate IoT devices and networks across a wide range of use cases, recognising the need for flexibility in IoT security.

Table 14 summarises the recent proposed IoT security solutions.

5.1. IoT Interoperability

IoT interoperability refers to the ability of systems to seamlessly communicate and collaborate across various IoT devices and platforms. It is essential for the success and widespread adoption of the Internet of Things [112]. Abdelouahid et al. [113] proposed a universal meta-model for IoT interoperability, which is based on organizational concepts such as service, compilation, activity, and architectures. The framework provides a structured approach for understanding and resolving interoperability issues in different IoT contexts. Muppavarapu et al. [114] conducted an in-depth study on IoT interoperability, offering a comprehensive taxonomy and identifying unresolved challenges. The research provides valuable insights for both academics and practitioners, guiding efforts to navigate the complex landscape of IoT interoperability. As a result, achieving interoperability is presented with both challenges and significant benefits. It enables seamless communication, data exchange, and collaboration among diverse IoT ecosystems [115]. To ensure effective interoperability, efforts should focus on refining protocols, aligning with international standards, strengthening adherence to security protocols, and ensuring scalability. Recent advancements in IoT interoperability include the proposal of standardized protocols, adherence to international standards, meeting security requirements, and scalability. Additionally, there is a growing trend towards incorporating blockchain technology to enhance the security of IoT devices. Figure 5 provides a summary of the proposed IoT interoperability model, illustrating the various components and interactions involved. As the IoT ecosystem continues to evolve, these developments serve as guiding principles towards achieving a more connected and interoperable future.

6. Conclusion

In the landscape of Internet of Things (IoT) applications, privacy and security emerge as pivotal considerations. While IoT holds the potential to revolutionize businesses and enhance our daily lives, it also presents significant challenges that demand careful attention. Privacy and security, particularly concerning data collection, anonymization, retention, and sharing, stand out as pressing issues. The influx of data from IoT devices offers immense potential for insights and innovation, yet it also raises concerns about personal data privacy, behavioral surveillance, and data exploitation. Therefore, addressing these challenges is crucial to ensuring the responsible and ethical deployment of IoT technologies, fostering trust among users and stakeholders alike. By implementing robust privacy and security measures, fostering transparency, and adhering to regulatory frameworks, the potential of IoT can be realized while safeguarding individual privacy rights and mitigating associated risks. Such endeavors are essential to unlocking the full potential of IoT in driving positive societal impacts and economic growth, while also ensuring the protection of privacy and security in an increasingly interconnected world. The findings underscore the intrinsic relationship between privacy concerns and the operation of IoT. As the IoT becomes increasingly integrated into our daily lives and industries, maintaining a steadfast focus on privacy and security is imperative. The diverse concepts and approaches highlighted in this survey offer a glimpse of a potential path forward. Through a combination of technological advancements, regulatory frameworks, and user education initiatives, we can navigate the complexities of IoT while safeguarding individual privacy and security.

As we embark on the ongoing journey of the Internet of Things, these insights and innovations will undoubtedly shape the trajectory of our interconnected world. By addressing privacy and security challenges head-on, we can unlock the full potential of IoT and create a future that is both technologically advanced and ethically responsible.

6.1. Future Trends and Innovations

In light of the vast opportunities presented by IoT, future industry standards should incorporate AI and machine learning into IoT devices and platforms. This integration enables the analysis of massive datasets, the extraction of meaningful insights, and real-time decision-making, thereby fostering more intelligent and autonomous IoT applications. AI-powered predictive maintenance enhances device performance and efficiency, while edge analytics improves data processing at the network’s edge, resulting in faster responsiveness and lower latency. Embracing edge computing in future designs reduces the need to transmit all data to centralized cloud servers due to its proximity to devices, leading to faster data processing, lower latency, and increased privacy and security, especially beneficial for real-time data analysis applications. Additionally, the integration of 5 G technology into these devices enhances their capabilities. To address security and privacy challenges, future research should focus on integrating blockchain technology, offering decentralized and tamper-proof data storage and validation, secure device identification, data integrity, and transparent transaction records.

Conflicts of Interest

The authors declare that there are no conflicts of interest regarding the publication of this paper.


This work was supported by the National Natural Science Foundation of China (Grant no. 62272076).