Blockchain has been primarily associated with finance and cryptocurrency, but it has also been used for various other applications in several domains and industries including healthcare, supply chain management, asset tracking, energy management, smart home/city and Internet of Things (IoT) [1,2,3,4,5,6,7]. For such applications and industries, Blockchain can offer benefits including transparency, accountability, Integrity, scalability, cost-efficiency, security, and privacy. While there are several current works proposed to adapt and apply Blockchain based architecture for IoT, and interconnected devices on edge networks, there is a considerable lack of research to propose and apply Blockchain for the core networks of Internet and its protocols, applications and services.
Currently, the Internet suffers from various issues and challenges in all layers. Most of these issues such as transparency, data integrity, authenticity, data privacy and security have clear correlations with the current multi-faceted embedded centrality of Internet from the client-server communication structure to the Public Clouds and Cloud-based applications. Revitalization of Internet is required through a more extensible and scalable Internet architecture that can address such issues and incorporate a broader scope of functionality .
In the prospect of finding ways to further improve the existing Internet model, there are two major approaches being spearheaded for the development of future Internet: Semantic Web and Decentralized Internet, the former suggests to connect every piece of information entity via Semantic technology in a way to be united into a singularity . The second generation of Web technology (Web2) introduced online services that brought in flaws of requiring centralized services, which is seen in client-server model. Semantic Web (Web3) aimed to extend Web2 using a data-driven model enabling integration across heterogeneous content, applications and systems through understanding data in machine-level. Semantic Web is progressing through heavily relying on machine learning and artificial intelligence (AI) methods to create more smart content and open Web applications for future Internet. However, the scope and the impact of Semantic Web is limited into application layer and it cant be relied as a complete solution to resolve some inherent Internet issues which have roots in centralized nature of current Internet.
The alternate approach is to decentralize and disseminate the Internet in all layers for equal role and authority power to prevent monopolization from online services . Some decentralization approaches have already proposed in current literature to resolve Internet flaws originated from centralization [11,12,13]. Also, in recent years, the popularity of decentralization has been further glorified in Blockchain due to its success in decentralization for cryptocurrencies .
The centralization of the Internet is not accomplished from a single night, but the gradual development of the Internet and its services over the years. The introduction of centralized services provided convenience and accelerated the maturity of the Internet. This acceleration from centralization made it widely dependent throughout the Internet. Although these centralized services have provided numerous advancements that have made up the current Internet, the bottom line is that a centralized service would still exhibit a centralized network’s vulnerabilities that would jeopardize the network. By having users relying on a centralized service, the users are opened to various types of attacks like Distributed Denial-of-service (DDoS) that could have been easily mitigated through decentralization.
The main motivation for this work came from the acknowledgment of reliance on centralized systems within the Internet . It is clear that according to  there has been a push for the development of the Internet to be consolidated into a central overseeing figure for administration. This matter of consolidation with information data is further provoked by privacy concerns caused by large organizations as part of the Big Data scheme.
Combating this centralization is achievable through decentralization with Blockchain. Blockchain has always been classified as a disruptive technology due to its impact for providing a decentralized solution for communication and transaction. This brings us to Blockchain’s consensus algorithms being capable of enforcing equal roles between peers. This enforcement would also keep these online services in check, preventing centralized power. The aspiration to obtain decentralization is broadened with the trend of implementing Blockchain into Internet Of Things (IoT), and to account for scaling to support the Big Data of the future Internet.
The Internet is a tremendously scaled, geographically distributed, global system of interconnected computer networks that uses the Internet protocol suite (TCP/IP) for communications across nodes and networks. It comprises various components, including infrastructures, hosts, devices, protocols, operating systems, services, and applications.
Throughout this paper, we frequently use the terms “decentralized Internet” and “Internet decentralization” to represent the concept of applying possible decentralized approaches in various levels and into any Internet components (e.g., decentralized protocols, applications, and infrastructure) in general and particularly for Web (so-called Decentralized Web, dWeb or Web 3.0). The original Web 1.0 introduced communication with Hypertext Transfer Protocol (HTTP) and established static web pages as content on the Web. Web 2.0 allowed users to collaborate and utilize server-side scripting to allow online services to proliferate. It is due to the growth of online services that led to the conceptualization of Web 3.0 being decentralized. Web 3.0 has been around as a concept since the early 2010s. The concept of Web 3.0 centers around user autonomy and not being reliant on centralized services, essentially having users be responsible for their data. The three generations of the Web can be seen in Fig. 1.
Current Internet model and architecture suffers from a large number of issues due to the impact of centralization. These issues include:
Scalability and availability Internet resources and services (e.g., computing, storage, network, and database resources ranged from single servers to large scale Cloud-based server-farms/datacenters) have limited capacity and cannot cope with the requirements of the increasing number of users without their direct contributions in providing resources. Large Internet companies may fail to provide resources to users in different geographical regions or over a specific time. This raises another issue, which is the availability of resources. In 2019, Microsoft Azure was reportedly running out of VMs for its customers in East U.S. . Similarly, in March 2020, Azure has suffered from a shortage in data center capacity due to a large amount of demands resulted by Covid-19 pandemic .
Reliability Services based on the client-server model are vulnerable to a single point of failure and bottleneck. They may fail to provide services due to problems like network or system failure.
Security and privacy Collecting user data by different service providers and storing them in a certain number of specific servers to support the hosting of various types of services and applications expose vulnerabilities and user data privacy to cybercriminals.
Trustability Large Internet corporations and service providers are trusted parties that can potentially maintain, control, and administrate user data, access, and activities. While this can bring benefits for the users, it potentially can be used as a source of control to apply surveillance or censorship, or it can lead to abusing trustability . In this paper, we provide a systematic review of the potentials and capabilities of Blockchain-based solutions which can efficiently be used for any aspect of the Internet decentralization. There are several other approaches for decentralizing the Internet, such as projects seen in Sect. 2.3. However, our focus in this paper centers around using Blockchain to decentralize the Internet. Also, it must be taken into account that Blockchain for IoT security is out of the scope of this paper due to space limitations.
In this paper, we consider the popularity of Blockchain for decentralization and the aforementioned Internet issues and provide the following contributions: (a) We identify that the current Internet is highly centralized, and we review challenges of centralized Internet and methods for Internet decentralisation. (b) We provide a detailed review on opportunities and challenges to use Blockchain as a key enabler for decentralization of Internet. (c) We explore and assess various Blockchain components, methods, techniques and algorithms with respect to the Internet open issues and provide a detailed review on Blockchain potentials to resolve the problem on centralization in current Internet. (d) We also provide a review on other emerging Internet relevant technologies to identify how they can be combined with Blockchain, covering its drawbacks to create a better solution for future Internet.
The rest of this paper organized as follows: Sect. 2 provides an overview of the current Internet architecture and what Blockchain is facing against, Sect. 3 revolves around understanding Blockchain’s components and challenges it would face on decentralization, Sect. 4 presents a list of consensus algorithms that have the potential to be a candidate for reaching consensus within the Internet, Sect. 5 discusses the emergence of future and old technologies that can be integrated with Blockchain, Sect. 6 presents a discussion of current and future technologies that can impact and benefit Blockchain in decentralizing the Internet, and finally Sect. 8 concludes the paper and discusses future works.