What is a Certificate Authority?

What is a Certificate Authority?

A certificate authority is a trusted entity that verifies the authenticity of websites, email addresses, organizations, and individuals and binds them to cryptographic keys by issuing digital certificates. A popular and most common example is the HTTPS browsing protocol for websites. Users can identify that they are connected to the original website and avoid falling victim to phishing scams. This website example is known as an SSL/TLS certificate. There are three different types of TLS certificates that CAs issue: domain validation (DV), organization validation (OV), and extended validation (EV).

Besides TLS certificates, they also issue other digital certificates, such as Code signing certificates, email certificates, device certificates, and user or client certificates, device certificates, and user or client certificates.

Certificate authorities use asymmetric encryption and Public Key Infrastructure (PKI) to issue certificates. Certificate authorities also maintain a Certificate Revocation List (CRL) to revoke certificates if the credentials have been compromised.

A public Certificate Authority is a third-party entity that issues certificates to other organizations/Because public CAs comply with the regulatory standards outlined by the CA/Browser Forum (CA/B Forum), they are widely accepted as a trusted source across the internet.

Some of the most popular public CAs are IdenTrust, DigiCert, Sectigo, GoDaddy, GlobalSign, Let's Encrypt, etc. In comparison, a private certificate authority is owned by an organization and follows internal procedures to confirm the security of that organization. It can be trusted within the organization's periphery and cannot be used for any external purposes.