We have provide offline credit card Integrations for this eCommerce web store. They have chosen us because our integration Offline Credit / Debit Card will allow customer:

Process order along with their cards
offline Card Capture for OpenCart
Automatically card information will be encrypted and send the email to the store owner.
This module will use the encryption key from the admin area as per store owner setup.
Store owner will be able to decode the encrypted information and will be able to use the card information to process order