> For the complete documentation index, see [llms.txt](https://docs.payments.thalescloud.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.payments.thalescloud.io/tokenization/implement-tokenization/post-tokenization-requests/visa-cloud-token-framework-ctf/cardholder-verification.md).
# Cardholder verification
This feature allows the Merchant to request end user verification from the Issuer at any time after a card is tokenized and, optionally, bound.
The objective of this feature is to give the Merchant a way to authenticate the end user. For example, the Merchant can use it after detecting suspicious activity on the end user account.
The following diagram shows a high-level flow and highlights the Issuer's involvement in the process.
High-level cardholder verification flow.
The diagram references [Approve with step-up authentication](/tokenization/implement-tokenization/card-tokenization-request/processing-the-response/approve-with-step-up-authentication.md).
This is the same flow used for Tokenization processing, with the following exceptions:
* The `Customer service` ID\&V method is not supported.
* The `In-app` ID\&V method can be supported through the D1 SDK. In particular, please refer to the section [In app authentication for Visa CTF](/push-provisioning/implement-push-provisioning/implement-view-and-control/in-app-authentication-for-visa-ctf.md).
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