Our checkout page is a secure page.

Actually there are two pages in the checkout page. The one you are "visibly" seeing in checkout section is a non-SSL page but the credit card information section is an iframe (second page) coming through SSL connection directly from CCAvenue. So, the card information is entered in https connection (please see screenshot got in Chrome browser by right-clicking "View Frame Info"). So, we can conclude there is no risk involved. 

Also, you would be aware of the SSL (Open SSL) attacks starting from Heartbleed upto Bar-Mizhvah. By implementing SSL alone, we should not come to the conclusion that everything is secure.

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