## 2 Related Work
### Certificate Management  
Starting with certificate management, certificates constitute a key piece of evidence of the skills and knowledge a person possesses in a particular field or profession. In today's job market, being a holder of certificates can significantly improve one's chances of finding a job and enhance his/her career advancement. Certificates such as university degrees are usually published in paper form, making them vulnerable on the one hand to loss and/or destruction and on the other hand to counterfeit. In the As-Is situation, the task of republishing a certificate or validating it requires the involvement of issuing organizations, thus creating overhead for their personnel. Blockchain can offer a solution to these challenges, as it can maintain a list of the issuer and recipient of each certificate along with the digital signature, i.e., the hash value in a public database, which is stored identically on multiple nodes of the network [8]. Digital certificates secured in this way on a blockchain have significant advantages over paper or even \"normal\" digital certificates. Firstly, they cannot be forged, given that each transaction produces a digital trail that confidently ensures that the document was issued by the university and for the person written on the document. Additionally, verification is performed by anyone with access to the chain. Moreover, blockchain requires no \"middlemen\" for the verification of a certificate, which can be verified even if the issuing organization no longer exists, given that the file itself cannot be deleted from a blockchain ledger. The aforementioned advantages have led to several research publications that propose methodologies and ICT tools aiming to facilitate certificate management and validation as well as increased security and data privacy [9; 10; 11; 12]. Specifically, in [13], the authors propose a blockchain application for certificate management and leverage smart contracts to automate processes and combat certificate fraud. The authors used the Embark framework to develop the application on the Ethereum blockchain. The advantage of utilizing the Embark framework is that it offers a wide array of capabilities that allow developers to configure a blockchain application from the backend to the frontend. The application prototype is very promising and shows the feasibility of using blockchain to develop applications for certificate management. Similarly, in [14], the authors propose the design of a blockchain system for certificate management that aims to enhance security through decentralization and also leverages smart contracts to optimize certificate verification. In [15], the authors showcase the early stages of development for a blockchain-based certificate management platform called BeCertify. What is noteworthy about the publication is that the authors provide a step-by-step overview of the early development of the platform, including the deployment of smart contracts, private key management, and the APIs that are necessary for a school to issue and verify a certificate. This process can be used by other research efforts as a guide on the steps for developing blockchain applications. Finally, in [16; 17], the authors performed comprehensive bibliographic reviews of existing blockchain solutions for certificate management showcasing the increasing interest of the research community in exploring the capabilities of the technology to develop robust platforms for optimized and secure certificate management. While the security and data privacy offered by blockchain are widely accepted, there are some concerns about the capabilities of future quantum computers to successfully attack such platforms by leaking the keys of individual nodes [18]. Such concerns have led to the generation of publications that review novel approaches for blockchain cryptography that are resistant to quantum computers [19].