The progressive evolution of digital communications requires ever more accurate and sophisticated protection, which is why this thesis focuses on the in-depth analysis of digital certificates, fundamental elements for ensuring the integrity and protection of information. The work is divided into two main macro sections: on the one hand, it offers a theoretical examination that describes how certificates work, illustrating the various types of certificates (EV, OV, DV), the chain structure and control mechanisms such as the Signed Certificate Timestamp (SCT) and Certificate Transparency (CT), with particular attention to the implications in terms of security and privacy. On the other hand, the original contribution of the thesis takes the form of the implementation of DigitalCertiAnalytics, a software designed ad hoc for the collection, verification and analysis of certificates, capable of operating on large-scale datasets, as demonstrated by the study carried out on 20 million domains.