Certification Authorities (CAs) are trusted organizations responsible for issuing, managing, and validating digital certificates in a public key infrastructure (PKI) system. These digital certificates are used to establish secure communications and authenticate identities over digital networks, such as the internet. When a user or a system, like a web server, needs to prove its identity, it presents a digital certificate issued by a CA. The CA validates the requester's credentials and issues a certificate that binds a public key to a specific individual, device, or service. Trust in the CA is critical; if the CA is compromised, the security of the entire system can be undermined. Many web browsers and operating systems come pre-loaded with a list of trusted CAs, and they will warn users if they encounter a certificate from an untrusted source. Certification Authorities play a vital role in enabling secure, encrypted communications and are fundamental to the integrity of a wide range of security protocols, including SSL/TLS for web security.