# Use Cases
source: https://developer.mastercard.com/mastercard-processing-authentication/documentation/use-cases/index.md

## Overview {#overview}

Each use case provides the following information:

* A brief description of the use case.
* A sequence diagram.
* A detailed explanation.
* A part of the API specification with endpoints used in the use case.  

The following use cases are provided, categorized by the authentication method selected by the issuer. During the API onboarding, the issuer will select a default method to be configured in the ACS, selecting from one of the following: 1, 2, 3a, 3b, 3c, 7, 8, or Lite.

|                                                                                                                         Use case                                                                                                                          | Authentication hub method |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|---------------------------|
| [Authenticate a 3D-Secure Transaction in a Frictionless Way Based on ACS Risk-Based Rules](https://developer.mastercard.com/mastercard-processing-authentication/documentation/use-cases/auth-trans-with-acs-risk-based-rules/index.md)                   |                           |
| [Authenticate a 3D-Secure Transaction in a Frictionless Way Based on the Issuer's Decision](https://developer.mastercard.com/mastercard-processing-authentication/documentation/use-cases/auth-trans-with-iss-decision/index.md)                          | `4`                       |
| [Authenticate a 3D-Secure Transaction with an Issuer's Mobile Application](https://developer.mastercard.com/mastercard-processing-authentication/documentation/use-cases/auth-trans-with-iss-mob-app/index.md)                                            | `3a`                      |
| [Authenticate a 3D-Secure Transaction with an Issuer's Mobile Application or a One-Time Passcode and Password](https://developer.mastercard.com/mastercard-processing-authentication/documentation/use-cases/auth-trans-with-iss-mob-app-alt/index.md)    | `3c`                      |
| [Authenticate a 3D-Secure Transaction with an Issuer's E-banking Service](https://developer.mastercard.com/mastercard-processing-authentication/documentation/use-cases/auth-trans-with-iss-ebank-service/index.md)                                       | `3b`                      |
| [Authenticate a 3D-Secure Transaction with a One-Time Passcode Sent by the Issuer](https://developer.mastercard.com/mastercard-processing-authentication/documentation/use-cases/auth-trans-with-otp-iss/index.md)                                        | `1`                       |
| [Authenticate a 3D-Secure Transaction with a One-Time Passcode Sent by the Issuer (Lite solution)](https://developer.mastercard.com/mastercard-processing-authentication/documentation/use-cases/auth-trans-with-otp-iss-lite/index.md)                   | `Lite`                    |
| [Authenticate a 3D-Secure Transaction with a One-Time Passcode Sent by the ACS Provider](https://developer.mastercard.com/mastercard-processing-authentication/documentation/use-cases/auth-trans-with-otp-acs-provider/index.md)                         | `2`                       |
| [Authenticate a 3D-Secure Transaction with a Password and One-Time Passcode Sent by the Issuer](https://developer.mastercard.com/mastercard-processing-authentication/documentation/use-cases/auth-trans-with-pass-otp-iss/index.md)                      | `7`                       |
| [Authenticate a 3D-Secure Transaction with a Password and One-Time Passcode Sent by the Issuer (Lite solution)](https://developer.mastercard.com/mastercard-processing-authentication/documentation/use-cases/auth-trans-with-pass-otp-iss-lite/index.md) | `Lite`                    |
| [Authenticate a 3D-Secure Transaction with a Password and One-Time Passcode Sent by the ACS Provider](https://developer.mastercard.com/mastercard-processing-authentication/documentation/use-cases/auth-trans-with-pass-otp-acs-provider/index.md)       | `8`                       |