# ThreeDSAuthenticationType

A model the API reference uses in a request or a response. The operation pages link every field typed as this model here.

How a 3-D Secure authentication reached its outcome. Recorded on
`ThreeDSAuthenticationData` so a reader can tell a frictionless approval from one the
cardholder had to complete, without re-deriving it from the transaction status and the challenge
flags.

## Values

| Value | Description |
| --- | --- |
| `Frictionless` | The issuer authenticated the cardholder from the risk data alone; no challenge was presented. |
| `Challenge` | The issuer required a cardholder challenge and the flow completed it (or the challenge was attempted and the issuer reported its result). |
| `Attempt` | The directory server or the scheme stood in for an issuer that could not authenticate and produced attempts proof (wire status A). Liability may still shift under scheme rules. |
| `RequestorInitiated` | A merchant-initiated (3RI) authentication with no cardholder present, run against a prior authentication. |

## See also

- [All documentation](https://devportal.demo.winkpg.io/llms.txt): the machine-readable index of every public page on this site.