PKI (Public Key Infrastructure)

A PKI (Public Key Infrastructure) is the system of CAs (Certificate Authorities), certificates issued by CAs, and the related infrastructure that enables secure communications on the internet.

With PKI, services, devices and users can authenticate themselves with certificates issued by CAs. These certificates can also be used for authorization, encryption and can ensure data integrity both for data at rest and data in transit.

Use cases for PKI include, but are not limited to:

• Securing web pages. Every HTTPS website uses PKI – a web browser trusts certificates issued by CAs (or delegates) whose certificates are in your operating systems certificate store. The website’s server’s certificate, issued by such a CA, proves the authenticity of the server and enables the encryption of traffic between a browser and the server.
• authentication and authorization for connecting to services, using mutual TLS authentication.
• email authentication and encryption.
• file encryption, i.e., storing encrypted backups on some servers.
• authenticating devices connecting to a VPN or a Wi-Fi.
• signing of software packages to prevent the installation of malicious software.