3D-Secure (used in Verified-by-Visa and MasterCard SecureCode) is extensible in two ways:
- <Extensions> element – this element can be used to transmit vendor specific elements as well as standard extensions (there is none at this moment).
- Custom message type – you can send new request/response message pairs like PAReq and PARes to either an ACS or the DS.
Both ACS and DS are supposed to be able to withstand hacker attacks, so it should be fairly safe to send unknown messages to them. Worst that can happen is logging. Same applies to custom elements dropped into <Extensions>.
This means it should be all right for each 3D-Secure vendor to start defining new message types and extensions. Of course, neither Visa or MasterCard will be happy with this, but these vendor extensions will allow 3D-Secure to evolve and survive far beyond what can be achieved by a central committee dictating each and every new 3D-Secure message types and extensions.
A very useful 3D-Secure extension is Form Fill. Why bother asking users to filling all the payment fields when all you really need is the credit card info? Just ask user to provide the card information and press the Buy button. If the card issuer supports form-fill, cardholder information necessary to complete the transaction will be returned in the Extensions. If not, ask for them. Since the user approved the transaction already by entering their PIN, they will be more likely to complete the transaction.
Another useful 3D-Secure extension is Digital Identity. Have the user login or sign-up for membership by entering their credit card info. If the ACS supports Digital Identity request, whatever information user allowed the card issuer to share with the merchant will be returned when asked by the merchant.
Extensions like these can and will make 3D-Secure the online payment protocol for the next twenty years.