# Retrieve Transaction Payload
source: https://developer.mastercard.com/mastercard-checkout-solutions/tutorial/authentication_scof/step3/index.md

## Step 3: Retrieve Transaction Payload via Checkout API {#step-3-retrieve-transaction-payload-via-checkout-api}

1. Call the [Checkout API](https://developer.mastercard.com/mastercard-checkout-solutions/documentation/api-reference/apis/index.md#checkout) with the proof of authentication (such as `authenticationResult`= AUTHENTICATED and `authenticationStatus`= COMPLETE in `assuranceData`) to retrieve the transaction payload.

2. Decrypt the authenticated payload to retrieve `assuranceData` object containing authentication parameters.

The following table shows the mapping between the authentication method and the decrypted payload:

| Authentication method used |                                                                                                                                                                                                                                                   Payload with an example of assuranceData                                                                                                                                                                                                                                                    |
|----------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| Passkeys                   | * DSRP cryptogram and cloud Token * verificationMethod = `07 - FIDO2 authentication` ```javascript { "assuranceData": { "verificationData": [ { "verificationType":"CARDHOLDER", "verificationEntity": "02", "verificationEvents": [ "01"], "verificationMethod": "07", "verificationResults": "01", "verificationTimestamp": "1709591301345", "verificationEvents": ["01"], "additionalData": "proof of passkeys authentication" } ] "eci": "02", } } ```                                                                                    |
| 3DS                        | * **threeDSOutputData** contains `dsTransId` and `authenticationValue` * verificationMethod = `01 - 3D Secure (3DS)` ```javascript { "assuranceData": { "verificationData": [ { "verificationType": "CARDHOLDER", "verificationEntity": "03", "verificationMethod": "01", "verificationResults": "01", "verificationTimestamp": "1709591301345", "verificationEvents": [ "01" ] } ], "threeDsOutputData": { "dsTransID": "d701e51c-45e2-45e1-8bdb-e53a4155c38b", "authenticationValue": "sjduwxiclotcscsvvseqdlitaamg" }, "eci": "02" } } ``` |