## 2 Background Literature Review
### Security Concerns in Smart Applications  
In general, the whole range of smart applications includes any kind of hardware and software that can be used to improve living standards, facilitate everyday tasks, and simplify the interaction between humans and the surrounding environment. This can include personal health monitoring devices, smart homes, smart environments, smart factories, smart grids, etc. [16]. The main idea is to utilize multiple sensors of the information to model the surrounding context of the environment and an optimized defined model according to requirements, often adaptive. A general IoT ecosystem normally has the following components, independently from the smart application, as presented by [PERSON] et al. [17]: _sensors_--simple passive devices that perform reading of measurements (temperature, brightness, etc), _actuators_--active devices that can perform actions (different servo-based elements), _IoT nodes_--end-point devices with limited computational capabilities (CPU \(\approx\) MHz) that are used to collect data, send measurements and often work using batteries or solar panels, _IoT gateways_--portable devices having the functionality of low-end personal computers (CPU \(\approx\) GHz), performing data processing and aggregation tasks, _Data Lakes_--redundant storage used for collecting historical data, processing and giving access to customers through the Internet. Part of the ecosystem is software that defines particular functionality and the system's response to environmental changes based on the sensors. However, the growing popularity of smart applications made them vulnerable to multiple attacks that have been successfully demonstrated during the last years as described by [PERSON] et al. [18]. The Mirai botnet demonstrated that the security and impact of the attacks on the IoT should not be underestimated [15]. The attack was successful due to multiple factors, including weak and default passwords, insufficient or absent implementation of industrial security standards, lack of privacy-by-design. To resemble the whole picture, it was studied how well privacy is implemented in the smartwatches by famous brands [10]. Due to the lack of such an omnipresent design feature, multiple users can be affected, especially, when the smartwatches are used by kids. A similar case was known from the German doll called _\"Cayla doll\"_, which is susceptible to attacks, also including eavesdropping over wireless communication [19]. The discovery of the indicators of compromise led to the ban of dolls and it has been pulled out of the market. Considering the aforementioned security concerns, there has been created a web portal _\"Slodan\"_ ([[https://www.shodan.io/](https://www.shodan.io/)]([https://www.shodan.io/](https://www.shodan.io/)), accessed on 21 September 2021) to monitor devices that are connected to the Internet globally. Searching for the generic keywords _\"Internet of Things\"_ we can get information about 9747 devices across the globe as of 10 February 2020. A corresponding search for the _\"webcam\"_ resulted in 4598 different devices currently online. It also can be seen that in both cases, many devices use some kind of HTTP webserver to deliver the information. In a matter of fact, even MCU is capable of running web servers that can be accessed externally such as Arduino ([[https://www.arduino.cc/en/Tutorial/WebServer](https://www.arduino.cc/en/Tutorial/WebServer)]([https://www.arduino.cc/en/Tutorial/WebServer](https://www.arduino.cc/en/Tutorial/WebServer)), accessed on 21 September 2021). Therefore, the amount of connected IoT devices is growing and the level of their capabilities is approaching consumer personal computers. Cybersecurity became one of the important requirements when it comes to the design of Information and Communication Technologies (ICT) systems, including IoT. It coversboth physical aspects such as sensors and actuators in remote locations and cyber aspects, i.e., data.