An SSL (Secure Sockets Layer) certificate is a type of digital certificate that is used to establish a secure, encrypted connection between a web server and a client (such as a web browser). SSL certificates are used to protect sensitive information, such as login credentials and financial data, that is transmitted between a website and its users.
When a client establishes a connection with an SSL-protected website, the server sends the client a copy of its SSL certificate. The client then verifies the certificate and, if it is valid, establishes an SSL-encrypted connection with the server. Once the connection is established, all data transmitted between the client and server is encrypted and protected from interception by third parties.
SSL certificates are issued by organizations known as certificate authorities (CAs), which are trusted third parties that verify the identity of the website owner and issue the certificate. There are different types of SSL certificates, including domain validation (DV) certificates, organization validation (OV) certificates, and extended validation (EV) certificates. EV certificates provide the highest level of security and are typically used by large enterprises and financial institutions.
To use an SSL certificate, a website owner must purchase the certificate from a CA and install it on the web server. Once the certificate is installed, the website can be accessed using a secure HTTPS connection.