SSL allows you to serve encrypted web pages to website visitors over the HTTPS protocol. Certificates must be signed in order to not set off browser flags that will question your site’s authenticity. But OpenSSL also provides the option to create a self-signed certificate, and many web hosting control panels have an option for it.
In most circumstances involving financial transactions, you should purchase a signed certificate, but there are instances when self signing will suffice. Some examples include private intranets, internal business groupware, web-based control panels, and other content backends. In all of those situations, you need encryption, but it does not matter to you if the certificate is official since you are the one who signed it.
You will still receive the browser warning the first time, but your browser should have a function that allows you to add your site to your browser’s trusted sites. From then on, you will not see the warning, although other users still would see it. If you ever decide that you do actually need to purchase a certificate, you can always change it later. For information about creating a self-signed certificate, see this site.
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