## 2 Literature Review and Research Gaps
### Related Works  
The Internet is a crucial tool for facilitating modern societal life. Through primary, traditional web browsers, and an Internet connection, users can access websites for social networking, online shopping, video streaming, public news, research, and more via the \"surface web\" [17]. The crucial distinction between the \"surface web\" and the \"clear web\" is that the latter phrase refers to the portion of the Internet that can be indexed by any traditional search engine [2, 5]. The deep web stands in opposition to the surface web. The deep web is a collection of websites, communities, networks, and intranets that are purposefully not accessible via standard online browsing, in contrast to the surface web, which makes its material searchable via ordinary search engines [3]. However, because of its anonymity, the dark web offers services to those who could have illegal intentions over a global network that is essentially untraceable [18, 19]. This raises an ethical problem due to the growth of the dark web, which has given rise to lucrative sectors like malware services, child pornography, and illicit Internet markets. In addition, the most prominent entrance to the dark web is TOR [8]. I2P is one solution used to access the dark web. Still, other anonymous software programmers like Freenet and OpenBazaar allow anonymous communications by storing and exchanging data via the machines linked to the network rather than utilising centralised servers [7]. Terrorist groups and extremist such as use the dark web to propagate propaganda, attract new members, and share data and films that support their illegal activities [15]. The dissemination of child pornography and unlawful online markets for illicit goods (drugs, weapons, passports) are the two crimes that are most frequently committed through the use of TOR [5]. However, other crimes include renting assassins and trafficking humans. One of the most well-known instances was the 2011 emergence of the drug bazaar on the dark web called \"Silk Road.\" The FBI shut it down in October 2013 after it had operated for two and a half years and processed over $1,200,000,000 in transactions [8]. The fact that criminals frequently feel safer transacting on the dark web than on the street is one of the significant elements causing this crime, as has been pinpointed in two recent studies on policing the dark web [1, 16]. Even if there is a higher likelihood that law enforcement will halt the business and take it offline, additional sites will replace it [10, 17]. Police and law enforcement agency shutdowns are one of the reasons why many dark websites are only active for a limited time, usually between 200 and 300 days, according to analysis [20]. Other elements that have influenced the rising use of online criminal marketplaces include the growth and acceptance of cryptocurrencies, as illustrated in Table 1.  
A 2016 study by RAND estimated that the three biggest online criminal markets at the time accounted for 65% of all crypto market listings. Cryptocurrencies like Bitcoin and Ethereum allow users to make payments anonymously as an additional layer of security [10]. In [19], a study was conducted to gain a deeper understanding of the dark web and its impact on people's lives. The researcher achieved the aim of his paper through the provision of various methods of access, the listing and description of available websites, and the provision of a list of precautions people should take before surfing the dark web. The article also discussed illegal activities and crimes committed on the dark web, its ethical and unethical sides, its pros and cons, and how legislative agencies and security agencies can administer the dark net to secure society. The study produced a robust research model on the dark web because it highlighted methods of accessing the darknet through various specific configurations, software, and authorisation.