SSL is an abbreviation for Secure Socket Layer which is a technology to encrypt data sent between a browser and server hosting a website. SSL is used to protect sensitive data from being passed insecurely over networks where it could be possible for someone to intercept or steal it.
Some of the payment gateways and in particular ones that require PCI compliance may store or transmit credit or debit card data. For this reason it is essential that this data is securely encrypted using SSL.
A website that uses SSL has https:// before the domain name instead of http:// and normally a padlock is displayed somewhere on the browser. In order for your website to be SSL secured you will need an SSL certificate for your domain name. For more information concerning this please contact your web hosting company who should be able to service SSL requirements.
A shared SSL certificate is often provided by your hosting company at no extra cost which is likely to be shared between other customers. For example your secure website address may look something like this:https://secure.examplehostingcompany.com/~yourusername
A dedicated SSL certificate will require an SSL certificate to be installed on the server which is specifically for your website and is likely to incur a cost from your hosting service provider.https://www.example.com
Many prefer this option for a more professional look.
Tip: Check to see if you can obtain your own SSL certificate rather than obtaining one from your hosting. This could save some money.