Types of Certificates

If you installed your Red Hat Linux Secure Web Server using the Red Hat Linux installation program, a random key and a test certificate are generated and put into the appropriate directories. Before you begin using your secure server, however, you'll need to generate your own key and obtain a certificate which correctly identifies your server.

You need a key and a certificate to operate your Red Hat Linux Secure Web Server — you can either generate a self-signed certificate or purchase a CA-signed certificate from a CA. What are the differences between the two?

A CA-signed certificate provides two important capabilities for your server:

Browsers will (usually) automatically recognize the certificate and allow a secure connection to be made, without prompting the user.
When a CA issues a signed certificate, they are guaranteeing the identity of the organization that is providing the Web pages to the browser.

You can generate a self-signed certificate for your Red Hat Linux Secure Web Server, but be aware that a self-signed certificate will not provide the same functionalities as a CA-signed certificate. A self-signed certificate will not be automatically recognized by users' browsers, and a self-signed certificate does not provide any guarantee for the identity of the organization that is providing the website. A CA-signed certificate provides both of these important capabilities for a secure server. If your secure server will be used in a production environment, you'll probably need a CA-signed certificate.

If your secure server is being accessed by the public at large, your Red Hat Linux Secure Web Server needs a certificate signed by a CA, so that people who visit your website can rely that the website is owned by the organization who claims to own it. Before signing a certificate, a CA verifies that the organization requesting the certificate was actually who they claimed to be.

Most Web browsers that support SSL have a list of CAs whose certificates they will automatically accept. If a browser encounters a certificate whose authorizing CA is not in the list, the browser will ask the user to choose whether to accept or decline the connection.

The process of getting a certificate from a CA is fairly easy. A quick overview is as follows:

Create an encryption private and public key pair.
Create a certificate request based on the public key. The certificate request contains information about your server and the company hosting it.
Send the certificate request, along with documents proving your identity, to a CA.
When the CA is satisfied that you are indeed who you claim to be, they will send you a digital certificate.
Install this certificate on your Web server, and begin handling secure transactions.