What is a certificate authority (CA)?

A certificate authority (CA) is fundamentally an organization that issues digital certificates. These digital certificates are critical components of public key infrastructure (PKI), which is used to secure communications over networks such as the internet. The CA verifies the identities of individuals or entities requesting certificates and, once verified, it issues a digital certificate that binds the public key to the subject's identity. This verification process ensures trust, allowing users to securely exchange information, perform secure transactions, and establish encrypted connections.

In contrast, while providing web hosting services, developing internet protocols, or managing network security are important roles in the IT field, they do not accurately define the primary function of a certificate authority. The core role of a CA is centered around authentication and the issuance of digital certificates, enabling secure data exchanges in various applications, such as SSL/TLS for secure web browsing.