Function: Validate credit card expiration date

Function: Given a number and algorithem, determine if we have a valid credit card format

Function: Validate credit card number based on the luhn algorithm

Function: Detect credit card type based on the number and return an array of data to validate the credit card number

Function: Determines if an email is banned

Function: Determines if secure checkout pages are enforced

Function: Handle redirections for SSL enforced checkouts

Function: Handle rewriting asset URLs for SSL enforced checkouts

Function: Filter filters and convert http to https

Function: Check if a field is required