3D Secure is a protocol designed to be an additional security layer for online credit and debit card transactions. The name refers to the “three domains” which interact using the protocol:
- Merchant/Acquirer domain (the financial institution and merchant to which the money is being paid).
- Issuer domain (the financial institution which issued the card being used).
- Interoperability domain (the infrastructure provided by the card scheme, e.g. Mastercard, VISA etc).