## TL;DR

Adyen 3D Secure is Adyen's implementation of the 3DS2 protocol for authenticating card payments: the shopper's bank verifies their identity, either frictionlessly in the background or via a challenge. For merchants it means PSD2 SCA compliance and liability shift on authenticated transactions. The practical work is in your integration: pass the required data, handle challenges, and read the result. Understand the two outcomes that matter: authenticated (liability shifts, capture with confidence) and not authenticated (decide your retry or fallback policy).

## The query

```text
adyen 3d secure
```

## Use this when

- Understanding Adyen 3D Secure before integrating
- Documenting payment authentication for stakeholders
- Evaluating Adyen SCA compliance

## Not for

- Writing the integration code (see the setup guide)
- Disputes on non-authenticated transactions

## Steps

1. Learn the two flows: frictionless background authentication vs customer challenge.
   Expected output: You can explain the UX to stakeholders.
2. Know what data your integration must supply for the risk assessment.
   Expected output: The technical requirement is clear.
3. Understand liability shift: authenticated transactions move fraud liability to the issuer.
   Expected output: The business case is quantified.
4. Decide the policy for non-authenticated transactions: retry, fallback, or decline.
   Expected output: Edge cases have answers before launch.
5. Confirm PSD2 SCA coverage for your EEA volume.
   Expected output: Compliance is verified, not assumed.

## Variant phrasings

### how does Adyen 3D Secure work

### Adyen 3DS explained

### Adyen Strong Customer Authentication

## Root cause

3D Secure moves the fraud decision to the party with the most data (the issuer) and compensates the merchant with liability shift; Adyen's role is plumbing that exchange reliably. The merchant's real job is handling both outcomes gracefully, not just the happy path.

## Edge cases

- Liability shift rules vary by region and card brand; confirm your mix
- Authentication does not guarantee authorization; the issuer can still decline

## Provenance

Resolved from the public thread: https://vectle.com/posts/pst_ktzc1WU0D6guv8fdoqEkQw