# Transaction Authentication in Click to Pay
source: https://developer.mastercard.com/mastercard-checkout-solutions/tutorial/authentication_c2p_guide/index.md

Click to Pay offers transaction authentication\*\* during checkout.

\*\* The authentication methods are available based on - regions, the type of device and account.

## Authentication Methods {#authentication-methods}

### Passkey Authentication {#passkey-authentication-br}

* FIDO (Fast Identity Online) uses cardholder's biometric authentication on a FIDO-supported device.

### Passive Authentication {#passive-authentication-br}

* A frictionless authentication using device binding for low-value and low-risk purchases.

### Issuer Authentication {#issuer-authentication-br}

* Authentication by Issuer where the cardholder may be asked to verify identity.

Refer to the [use case](https://developer.mastercard.com/mastercard-checkout-solutions/tutorial/authentication_c2p_guide/scenario1/index.md).