# Trusted Academic Transcripts on the Blockchain: A Systematic Literature Review
## 6 Discussion  
The breadth of research investigated and outcomes proposed herein is vast and non-trivial. The proposed blockchain applications diverge according to the issuing institution, underlying platform, and model. On the other hand, the selected material is perceived as sufficient and exhaustive to provide interesting remarks. Despite the plethora of studies proposing and experimenting with alternative blockchains, Bitcoin is still the most widespread and utilized platform for academic transcripts [51; 52; 68]. However, the solution to upload documents in bulk to overcome limitations related to high costs, congestions, and scalability is still debated. The most popular alternative is the Ethereum blockchain, which is moving to a proof-of-stake consensus mechanism. Unfortunately, all the studies are based on the proof-of-work consensus mechanism, and it is unclear how (and if) the change to proof-of-stake will impact academic applications [95; 96]. Follow-up work should be conducted to determine any impacts on fees and congestion. Regardless of the platform type, it emerges from the selected studies that universities, students and employers, would like more than just the ability for a transcript to be notarized on a blockchain and that detailed skills should be permanently stored on the ledger [8; 32]. Doing so, the amount of data to be managed would dramatically increase, raising also concerns about users' privacy. Clearly explained by [PERSON] et al. [72], the introduction of the GDPR makes it inconvenient to store students' records permanently online. Therefore, as well as for interoperability reasons, the implementation of a database is considered a must for academic applications [69; 70]. On the other hand, the addition of a database would also increase centralization and potential vulnerabilities. Finally, a user-friendly interface that is easily utilizable by students, as well as employers or verifiers, is highly demanded [19; 88]. Moreover, usage of the interface should not require any specific knowledge on blockchains to be operated. A summary of those characteristics can be found in Table 4.  
Diverging views emerge on the concept of issuing authorities (nodes), whether a blockchain should be public, private, and consortium-based. Hyperledger or ad-hoc blockchain proposals mainly consider a closed system as the only one capable of guaranteeing privacy and tamper-proof certificates [11; 21]. However, a closed system for the issuance of certificates clearly affects the oracles' trustworthiness and auditing process. Few but illuminating contributions to the oracle problem issue provide many insights into how a project may be more robust. Researchers agree that for the oracle to be trusted and the system to be auditable, it should run on an open and public blockchain [46; 70]. A closed system requires users to rely on the good-faith of the institutions or unknown auditors. Furthermore, the communication channel between the academy and blockchain should be transparent, and the identity of human oracles known [28,98]. As a blockchain oracle, the university can surely benefit from its long-term reputation but will be able to provide less info on the student's specific skill. On the other hand, If a professor is himself a blockchain oracle, given his personal reputation and skills, he should be able to provide more detailed information on the students' performance. Furthermore, if the oracle's identity is unknown, then the transcript's data gain no more value for being on the blockchain. The oracle's reputation and skill give more value to certified talent and accomplishment [99,100]. Furthermore, providing false attestation would undoubtedly undermine the issuer's reputation, which should represent a sufficient deterrent to undertake selfish strategies. On the other hand, having identities and positions made identifiable exposes oracles to tampering, threats, and corruption.