A Blockchain-Based Approach for Certifying Information at Different Levels of Granularity According to the Data Minimization Principle of the GDPR

In today's age, ensuring the integrity and authenticity of digital information is an important aspect in various domains such as healthcare and education. Unlike traditional digital certificates that primarily authenticate identity, attribute certificates provide additional information about a subject's attributes, such as roles, qualifications, or membership status. The General Data Protection Regulation (GDPR) underlines the principle of data minimization, emphasizing the collection and processing of only necessary personal data for specific purposes. In this paper, we deal with the need to certify attributes and satisfy the data minimization principle, thus designing a technique for certifying information at various levels of detail. The proposed framework utilizes blockchain smart contracts to automate the certification process, ensuring the authenticity and integrity of certified data. A proof of concept of the technique is presented in the context of certification in online education.