Public key infrastructure

A PKI is the overall implementation of certificates and CAs to establish, manage, distribute, and revoke digital certificates and public keys, which are used for authentication, encryption, and digital signatures. As the name suggests, a PKI relies on public key cryptography—that is, a pair of public and private keys.

There are many use cases for the implementation of a PKI; however, to understand it better, we’ll take the example of https, as follows:

1. When you visit a website that has https in its URL, a PKI is used to secure the connection between your computer and the website. When you initiate a secure connection, your browser sends a request for the website’s digital certificate that contains its public key.
2. The website responds with its digital certificate, and your browser uses the PKI to verify the certificate’s authenticity, making sure it was issued by a trusted CA and that it has not been revoked.
3. Once...