> For the complete documentation index, see [llms.txt](https://doc.ecomm.api.tietoevry.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://doc.ecomm.api.tietoevry.com/features/3d-secure-authentication.md). # 3D Secure Authentication 3D Secure (3DS) is an enhanced authentication protocol that adds an extra layer of security to credit card transactions, helping to prevent fraudulent activities. During payment, customers must verify their identity with the card issuer, typically through a one-time password (OTP) or biometric authentication. In most cases, the merchant redirects customers to their bank's verification page, where they enter a password linked to the card or a code sent to their phone. Customers may recognize this process under different card network brand names, such as: * Visa Secure (Visa) * Mastercard Identity Check (Mastercard) ### Regulatory Compliance & Fraud Prevention Under the Strong Customer Authentication (SCA) requirements outlined in PSD2 (Europe) and similar regulations in the UK, India, Japan, and Australia, the use of 3DS is mandatory for certain card payments. In regions where 3DS is not required, businesses can still enable it as a fraud prevention tool, enhancing transaction security and reducing unauthorized payments. Test --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter: ``` GET https://doc.ecomm.api.tietoevry.com/features/3d-secure-authentication.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.