Client certificate-based authentication is a method of authentication that uses SSL/TLS certificates issued to clients by a trusted Certificate Authority (CA). Here is how it works:
1. The client requests access to a secure resource or service on a server.
2. The server sends a certificate request to the client, requesting that the client send its certificate.
3. The client sends its certificate to the server.
4. The server verifies the certificate signature and checks that the certificate has not been revoked by the issuing CA.
5. If the certificate is valid, the server checks the certificate’s subject name against a list of authorized clients, and if the certificate is on that list, grants access to the requested resource or service.
In this process, the certificate serves as proof of identity for the client, and the server trusts the certificate because it was issued by a trusted CA. This type of authentication is often used in high-security environments where traditional username and password authentication are not sufficient.
