A Certificate Signing Request (CSR) is needed in case you want to acquire an SSL certificate which will encrypt all of the payment and account info which will be exchanged between your site and its customers. The CSR contains information about the site plus its owner in Base64-encoded form - web address, physical address along with email, company name and unit, and the like. Based upon this code, a licensed SSL vendor issues the certificate, that is digitally signed with the vendor's private key so as to recognize that they are a reliable issuer. At the time of the CSR generation, a unique private key is also generated and the installation of the SSL involves all of the four codes - both the keys, the certificate as well as the CSR. Then, you'll be able to use a URL starting with https:// for your site instead of http:// and the site visitors can view the information that you've provided for the CSR via their web browsers.