Public Key Infrastructure

Public Key Infrastructure (PKI) is the system of policies, roles, hardware, and software that creates, manages, and validates digital certificates.

Its core job is to bind a public key to a verified identity (a website, a person, or a server) so others can trust it.

Public-key cryptography lets anyone publish a public key. But how do you know a key really belongs to bank.com and not an attacker?

PKI solves this by having a trusted third party vouch for the key by signing a certificate.