Public Key Infrastructure (PKI) is a comprehensive system composed of hardware, software, policies, processes, and procedures designed to create, manage, distribute, use, store, and revoke digital certificates and public/private cryptographic keys. PKI is foundational for enabling secure digital communications, authentication, and data integrity across networks, particularly in environments where sensitive data is exchanged or strong identity verification is required.
PKI enables secure data transmission using asymmetric encryption, which involves a pair of cryptographic keys—a public key (shared openly) and a private key (kept secret). Data encrypted with the public key can only be decrypted by the corresponding private key, ensuring confidentiality. PKI uses digital certificates to verify the identity of users, devices, or services. These certificates are issued by trusted entities called Certificate Authorities (CAs), which vouch for the legitimacy of the certificate holder. PKI supports digital signatures, which provide proof of origin and ensure that data has not been tampered with in transit. By binding identities to public keys through digital certificates, PKI guarantees that data comes from a verified source and cannot be repudiated later.