# Challenges of Using Blockchain in the Education Sector: A Literature Review
## 3 Results
### Challenges of Blockchain in Education
#### 3.2.1 Technological Barriers
* _Lack of scalability_ Blockchain was first presented as a decentralized cryptocurrency; however, with the development of distributed ledger technologies (DLTs) and the emergence of smart contracts, this technology has grown significantly and is used in non-crypto currency domains, such as education, health care, and the supply chain [52]. With this growth in the number of users, scalability issues arise. Scalability is defined as the ability of a system to continuously respond and operate after increasing the input size to meet user demand [49]. In the context of blockchain, [PERSON] and [PERSON] [18] defined scalability as the challenge of slow-speed blockchain transactions. However, this review showed that six articles [7; 8; 11; 12; 18; 26] reported that blockchain applications in education may suffer from scalability issues, which limits their broad use in the education domain. Educational systems have collected large amounts of data on many students, resulting in an increase in block sizes [11]. With the increasing number of blocks, transactions in the blockchain need more time because each transaction needs peer-to-peer verification [11]. Therefore, a major technological challenge of blockchain, especially for public blockchains, is the network's technical scalability, which can hinder its general adoption, as is the case with the education sector [7; 52]. In comparison to other systems, blockchains are slow, with generally long transaction times [26] and limited storage capability [27], which could be a significant constraint in some academic settings. The ability of legacy networks to perform thousands of transactions per second is well-known. Visa, for instance, can process around 1667 transactions per second [53]. In terms of transaction speeds, however, the two most popular blockchain networks, Bitcoin and Ethereum, remain far behind. While the Bitcoin blockchain can achieve 3 to 4 transactions per second, Ethereum can process around 20 transactions per second [53]. However, the scalability issue relating to the speed of blockchain transactions is dependent on the type of educational application that was developed [11]. Slow blockchain transactions for credentialing, for example, can be a smaller problem, but processing educational tokens or trying to pay university fees on the blockchain, given the remarkably low number of transactions possible per second, may be a bigger problem [11]. In addition, there is a difference between public and private blockchains. Private blockchains may be implemented in a stricter context, where it is vital to restrict who can enter and participate in the network, whereas public blockchains are not constrained in terms of access permissions and allow all users to append new blocks [24]. Therefore, a lack of scalability is not a problem for private blockchain networks, as network nodes are designed to manage transactions within a trusted environment [54]. Another potential scaling issue is that proof-of-work, the widely used consensus protocol for the verification of new blocks, expends a substantial amount of electrical energy [12]. For example, it is well known that Bitcoin proof-of-work wastes enough electricity per year to supply a country the size of Switzerland [11]. In this context, [PERSON] [8] argues that proof-of-work is the most challenging issue in the education sector. Therefore, due to its high electricity usage, the proof-of-work blockchain in education poses a risk to climate change and imposes a greater carbon footprint [55; 56]. However, the blockchain platform type used in educational applications must be considered; for example, some solutions [15; 16; 19; 33; 40; 41] used the Ethereum platform (see Table 2) because it offers a stable and secure solution for their needs. Other solutions [57] have used other types of platforms, such as the Stellar blockchain, which uses less energy than Ethereum because it relies on its federated Byzantine fault tolerance (FBFT) consensus algorithm, rather than expensive proof-of-work computations.