PKI, or Public Key Infrastructure, is the framework that creates, distributes, stores, and validates digital certificates and cryptographic keys. It lets systems prove identity, encrypt traffic, and verify that software or devices are trusted. In practice, PKI includes certificate authorities, certificate chains, private keys, and trust stores.
PKI matters because many security controls depend on it. If an attacker can steal a private key, issue a fake certificate, or change a trust store, they may impersonate devices, intercept encrypted sessions, or sign malicious content as legitimate. In industrial systems and other networked environments, weaknesses in PKI handling can expose configuration files, enable unauthorized access, or break secure communications. Defenders use PKI carefully to authenticate endpoints, protect updates, and limit which certificates are accepted.