# Blockchain Applications in Education: A Systematic Literature Review
## 3 Results
### Summary of Contributions  
In this section, a summary of each publication is provided, including the implemented blockchain technology when identified by the author or authors. A comparison of the main contributions and a categorization of each article is offered in Section 4. Figure 2: Selected articles by year. In [13], [PERSON] and [PERSON] propose a model to store student's transcript information so that it could be transferred among universities to support learner's mobility. The solution is prototyped with two different approaches, both using blockchain technology. In the first case, Ethereum is combined with the Neo4j open-source NoSQL database. BigChainDB, a distributed database system, is utilized in the second case. The contribution by [PERSON] and [PERSON] [14] introduces a service to issue academic certificates that can be verified by recruiters. The implementation is based on the Hyperledger Fabric framework and the authors discuss a proof of concept of this initiative. A different approach is proposed by [PERSON] et al. [15], as they report the design of an automated bursary payment system for universities. Their platform is technically modeled as an extension of the Bitcoin structure, with a DLCC (Digital Learning Chain Structure) blockchain. Using smart contracts, the processes between students and universities are autonomously executed: a grade book is queried, progress is assessed, and cryptocurrency is transferred to the student's account if the requirements are met. The article also includes the results of empirical research about the students' opinions about Bitcoin and the proposed platform. [PERSON] et al. [16] discuss the design, prototype and characterization of a badge-awarding system to assess achievements in education using blockchain technology. The resulting platform is compatible with IMS Global Learning Consortium's Open Badges [17]. The process of earning a badge is verified by the Ethereum network and events are tamper-proof and recorded in the blockchain, so that anyone can check if a badge is valid. The proposal by [PERSON] et al. [18] is oriented to create a system to authenticate learning resources in massive open online courses (MOOC) for teachers and students using  
Figure 4: Number of publications by country. Figure 3: Number of publications by continent. blockchain technology to avoid malicious data tampering and other information security problems. After learning contents are registered on the platform, learners can verify their validity before using them. UniChain is described, prototyped and its performance analyzed in the paper by [PERSON] et al. [19], an Ethereum-system to issue and manage academic certificates that can be trustfully accessed and shared among students, universities and other third parties, while keeping students' privacy by means of time-based smart contracts. It also proposes an incentive mechanism based on the commitment of academic institutions regarding their efforts towards maintaining records and adding new ones. Another model to issue and verify academic certifications based on blockchain to reduce the incidence of certificate forgery is proposed by [PERSON] and [PERSON] [20] but, in this case, the blockchain technology used is not specified. A different application field is addressed by [PERSON] et al. [21], who model a combination of a generic public and private blockchain-based platform to manage and share multimedia contents in online education. It enables the creation of lifelong trusted learning academic certificates for learners, helps protecting digital copyrights of multimedia works shared by educational entities and, therefore, promotes the establishment of a community to share globally multimedia educational resources. An initiative to share exam questions and protect them from being leaked is proposed and analyzed by [PERSON] et al. [22]. Question papers are encrypted with a timestamp and trustfully stored in the blockchain with a smart contract that controls when they can be accessed.