1. Introduction

Because individuals worldwide are concerned about their health, the body sensor network assists with collecting essential body details of the individual through sensing devices. Although the wireless body sensor network (WBSN) has greatly interested in environmental and medical applications, safety and privacy are still significant issues [1]. Because it is distant, there are possibilities for various challenges such as a lack of energy, a degraded platform's capability, and fake concern. Furthermore, the data shared through the wireless body sensor network (WBSN) is subject to various harmful threats [2].

While the patient's status is transferred between the physician and the patients, any intruder can intercept incoming packets between traversing via wireless signals and rebuild the results. This could put the patients’ lives in danger. Any patient with a socially unacceptable condition should have their details handled carefully. As a result, we must ensure that the confidentiality and anonymity of any type of information are protected and transmitted securely. As a result, different intrusion prevention techniques are needed to protect against these assaults. The guarantee of the security and safety of the information obtained has been critical. According to experts, BSN has been the target of numerous assaults in recent decades, ranging from specific functions to the overall network. As a result, experts continually develop new adaptations and combinations of traditional security procedures to defend against such assaults. Security is a significant issue for BSNs, according to surveys. Similarly, several studies [3-5] have revealed a general shortage of studies in BSN protection.

The scholars previously published a Systematic Literature Mapping (SLM) of BSN security features, highlighting the experts' scientific literature's immense unexplored skills and experience [6]. Though earlier surveys of security checks research for BSN exist [7, 8], we could not find any that included grey literature(GLR). This article discusses a Multivocal Literature Review (MLR) of security mechanisms in BSNs, which surveyed source papers in academics and GLR to address this gap. According to the scholars [9], the most commonly used and approved description of GLR is literature obtained in all areas of government, academic institutions, companies, and economy, in both traditional and digital formats, but just not governed by conventional publishers, i.e., where publications may not be the main activity of the manufacturing body. MLRs are a sort of Systematic Literature Reviews (SLRs) that include knowledge from a range of resources, such as scientific research (i.e., academia "papers") and corporate "grey" literature (i.e., blog posts, white papers, videos, presentations, and similar).

The study that is being suggested is a multivocal literature study that was conducted on security methods for BSN. In total, the assessment discovered 10871 academic publications and 697 pieces of grey content. Following the exclusion of duplicates and the adoption of selection criteria, the research obtained 73 academic articles and 30 grey articles.   When classifying the specified security solutions inside each article, different standard security methodologies, scope, and security scenarios were evaluated. In order to get answers to the issues that were posed, it was essential to ask questions regarding the number of publications, the techniques of research, the safety procedures, and the contexts.    The results of our survey show that security mechanisms and evaluations are divided into 15 categories, with authentication and authorization being the most commonly mentioned. The mass of strategies focusses on avoiding and alleviating security flaws, while just a small number of works focus on detecting and recovering.

By providing experts and researchers with a comprehensive collection of security tactics and procedures, this review could be the first step toward making the BSN framework more reliable. After researching the most often used security solutions, experts will use these solutions to fix security concerns and build a trusted BSN.

The following sections constitute the rest of this article: Section 2 summarizes the security issues confronting BSN; Section 3 highlights related research. Section 4 discusses the article's methodology; Section 5 outlines the findings; Section 6 identifies future research directions; Section 7 identifies application examples for our multivocal literature review; Section 8 discusses validity concerns, and Section 9 summarizes the findings.

2. Security in Wireless Body Sensor Network

A patient’s medical state can be monitored using telemonitoring systems. The rising expense of medical services, the increasing elderly population, and the rise in chronic disease patients worldwide are driving up demands for alternatives in the healthcare sector. Because of these challenges, conventional health care cannot achieve the needed flexibility. As a result, high-performance, low-cost, and appropriate care solutions are required. The Wireless Body Sensor Network (WBSN) is a wireless platform that allows sensors attached to a patient’s body to communicate to monitor the body's essential parameters and surroundings. The use of wireless sensor nodes in public healthcare tracking opens doors for delivering superior patient care. For example, at-risk individuals with a background of heart problems or aged individuals who live independently can be monitored using various sensors. These sensors allow physicians to diagnose diseases more efficiently by providing ongoing, long-term tracking in an invisible manner [10]. A body sensor network, or BSN, is a collection of sensors placed on the person's body to gather physiological signals [11].

In recent research and industry, the design and implementation of such WBSN approaches to health monitoring have gotten a lot of interest. This focus is primarily driven by the high cost of health care and recent advances in the manufacturing of micro health applications and new technologies like the Internet of Things (IoT), contributing to the 5G's main obstacles. An explicit approach to handling the basic software design and validation should be advantageous for building and maintaining such systems. At various spots, the sensors observe and compare the circumstances. Environmental (e.g., pollution levels, weather, and moisture) and essential human functions are typical examples (e.g., heart and brain signals). A WSN can sense, process, and communicate. To acquire data on the centralized environment, diverse WSN-based monitoring apps have been created in many application sectors. Defense applications [11], global warming tracking applications [12], apps in submarine networking [13], and apps in health monitoring [14] are only a few examples.

Regardless of these applications, security has become a significant challenge. The system must ensure the security and privacy of the collected individual health data. Decomposing activity results in an increase in the platform's flaws and renders it more complex to implement the security architecture. This has resulted in a slew of BSN privacy discussions, the most important of which are discussed and taken in context hereunder [15].

The developers [16] suggested a secure platform based on heart rate frequency. They used the measurements of the inter-pulse periods to build binary patterns from the beats. In 8 seconds, they generated a 128-bit sequence using ECG records from the MIT-BIH Arrhythmia dataset. As a result, they could minimize the time it took to generate a random sequence of bits. The fundamental issue with employing a heartbeat as a security measure is inconsistent over time. The person's health records should be protected to avoid information misuse, and the patients should be able to reach the practitioner at the appropriate time and without delay. SEKBAN (Secure Key Management in WBAN) is an innovative approach that addresses security issues at three stages. By constructing keys relying on the ECG signal, this suggested technique protects the data's privacy[17].

Depending on the ECG monitor, the researchers offer [17] a body sensor network encryption and user authentication (BSN-EUA) approach. The BSN-EUA method provides fingerprint recognition for identity verification, and all of a person's health-related activities are logged on the handset. The descriptive properties of the electrocardiogram (ECG) are employed as a recognized fingerprint feature all through the access control mechanism. When modest alterations are required to modify the cryptography technique on the sensor's side, rapid social security protocols are given across all approved sensors. The research results reveal that the proposed method meets the required privacy standards. The authors in [18] presented a symmetric security technique for WBAN that uses the ECG wave to produce and deliver the secret key. WBAN nodes should sense the ECG data using a synchronization approach to make the security key. The suggested method's stability is demonstrated using formal and informal security assessments.

Any breach would not only harm the patients' security, but it might also put their lives at risk. For example, providing physicians with a misleading ECG sensor readout may result in inappropriate actions that are potentially hazardous to patients. When a mechanical insulin pump gets a faulty or corrupted signal, it may deliver an excessive amount of insulin into the patient's veins. WBAN is vulnerable to a wide range of assaults, from interior to exterior, passive to active.

In terms of addressing potential security issues, all of the studies listed above reference security measures that range from conventional security mechanisms like encryption and authentication to Intrusion Detection Systems (IDSs) and Trust Management Solutions (TMSs). For WBANs to be a success and be widely adopted, developers must focus on security solutions and authentication mechanisms for data and services.

1. Conclusions

EHealth is becoming a popular issue not only in the science community, but also in the manufacturing and commercial worlds. Information and communication technologies, which are both new, have a lot of capability to make the public healthcare platform better. There are a few problems with a digitalized healthcare system, like security worries, system unscheduled downtime, and loss of security for patient information. With the aid of technology, WBSN clients can get to their body sensor data and other resources from all over the world. It will assist reduce the cost of diagnosis, improve services, give better analytical reports, and speed up the process of getting care. But although there are a range of advantages, data security and privacy were still major concerns. So, in this article, we've discussed about security and privacy problems and suggested solutions.

As part of our research, we looked at 73 ALR and 30 GLR studies to understand the different privacy aspects that have already been employed to secure BSN. This study's findings show that authorization, access control, and authentication protocols are the most popular protection techniques in BSN research and practice. Furthermore, the review reveals that avoiding and mitigating threats are perhaps the most common security approaches, and a large number of security measures are validated via case studies and simulations. According to a proposed analysis, it is also found that probably the most common research type is evaluation research.  These findings led us to make a range of research recommendations. In the proposed study different methods are looked at to see how the security of patients' health data can be improved. We assume this will be the 1st multivocal survey of BSN safety and, therefore should be helpful for practitioners and scholars.

But there is still a big necessity to find better and more creative ways to deal with the growing sophistication due to rapid development and advancement of wireless sensor networks used in vital applications now and in the coming decades.

This entry is adapted from the peer-reviewed paper 10.3390/asi5040079