What is a certificate authority (CA) and what is its role in HTTPS?

What is a certificate authority (CA) and what is its role in HTTPS?

• A. A CA issues digital certificates that verify the identity of servers; browsers trust CAs to establish TLS/https connections
• B. A CA encrypts data in transit
• C. A CA stores user passwords in a database
• D. A CA blocks malware attachments

Answer: (A)

In HTTPS, establishing trust is the key idea: you need to know you’re talking to the real server. A certificate authority issues digital certificates that bind a server’s identity to a public key, and browsers trust those certificates because the CA’s root keys are kept in the browser or OS trust store. When a connection is made, the server presents its certificate during the TLS handshake, and the browser checks that the certificate is signed by a trusted CA, that the certificate is valid (not expired or revoked), and that the domain matches. If everything checks out, a secure, encrypted channel is created so data can travel safely. The other options describe different roles (encryption of data, password storage, blocking malware), which aren’t what a CA does.

In HTTPS, establishing trust is the key idea: you need to know you’re talking to the real server. A certificate authority issues digital certificates that bind a server’s identity to a public key, and browsers trust those certificates because the CA’s root keys are kept in the browser or OS trust store. When a connection is made, the server presents its certificate during the TLS handshake, and the browser checks that the certificate is signed by a trusted CA, that the certificate is valid (not expired or revoked), and that the domain matches. If everything checks out, a secure, encrypted channel is created so data can travel safely. The other options describe different roles (encryption of data, password storage, blocking malware), which aren’t what a CA does.