My masters thesis, supervised by Athena Vakali, was based on blockchain technologies with the title “PKI Decentralization Using Blockchain Technologies”.
The Public Key Infrastructure (PKI) is used widely on the Internet in order to certify the identity of users, and as a result encrypt the communication between two parties and make it more secure. From this model, multiple problems can arise, most of them due to its centralized nature. In the past, there have been cases of Certificate Authorities distributing rogue certificates that resulted in attacks, targeting users of the system. In most of these cases, it is really difficult to detect and revoke these certificates, and as a result, users remain vulnerable. But even if the certificate is revoked, the user update process is really slow and inefficient, resulting in even more implications.
In order to fix these issues, two different decentralized PKI alternatives has been developed, using blockchain technologies like Bitcoin and Ethereum. In the models and implementations that have been developed, the transparency, immutability and decentralization aspects of these blockchain technologies has been leveraged. Leaving aside the centralized Certificate Authority aspect of the traditional PKI, the resulting system is more secure, more reliable, cheaper and open.