# Blockchain Applications in Education: A Systematic Literature Review
## 4 Discussion
### Research Question 3: What Are the Unresolved Issues of Blockchain in Education?
From the GDPR's point of view, hashing personal data, as used in different initiatives, cannot be considered an anonymization technique [51]. In other countries, for example Brazil, public education allows private data to be publicly available, while in private education it must be protected [32]. The immutability feature of blockchain technology can also be problematic, as it prevents any chance of deleting educational data even for legitimate reasons both for academic institutions, learners or third parties. These can be modified by authorized entities, but the original information will be recorded forever in the blockchain, and this collides with GDPR's right to be forgotten. In general, the legal aspects of blockchain in education are still to be addressed, and there are regulatory and governance barriers [25]. A standard regulation across the many different education systems and jurisdictions in the world would be necessary to expand the applications of blockchain in this field. For example, the owner of the data when shared in a P2P network must be defined [36]. Scalability and performance are also unresolved topics when the number of transactions increase, and blockchain technologies are not perceived to be ready for general adoption, which is also the case in the educational field [25]. However, the relevance of this issue depends on the actual application and the flow of information and participants. Blockchains are slow with typically high transaction times [46] and have a limited storage capacity [26] compared with other systems, which could be a real limitation for some academic scenarios. The consensus protocols, especially those utilized in public blockchains, waste a lot of energy and resources (i.e., bandwidth, storage, computing, etc.) to keep the information reliable [43] and more research is required to address these issues. For many institutions or countries, the widespread use of blockchain in education may involve high costs. Again, this depends on the specific usage, the selected type of blockchain and how its features are valued (e.g., availability, immutability, etc.). For example, the use of Tangle with no transaction fees [43] or government-controlled blockchains with highly efficient nodes to centralize information and lower the cost of operations [30] are proposed. [PERSON] et al. [31] discuss who should pay the costs of generating lifelong learning records, namely students or learners, and therefore it should not be excessive. Note that, in the case that a public blockchain is used, the fluctuance in the tokens' value must be considered [46]. On the contrary, in private and consortium blockchains these fees are lower [32], and there is no price variations due to market conditions, but the whole network must be deployed and maintained. Additional challenges must be addressed according to the reviewed documents. Blockchain can store and assure the validity of the content of transactions, but not the authenticity of the learning. The quality of information and interactions still depend heavily on humans, that is, teachers and learners [25]. Education comprises many processes beyond evaluation and certification, and there are many assessment scenarios in the real world (e.g., exams, but also presentations, interviews, real time controls, group projects, class participation, etc.) that are difficult to model with blockchain and smart contracts [25]. More research about the combination of education with blockchain is needed to model and solve these challenges.