#  Token Authentication Service 
source: https://developer.mastercard.com/transaction-authentication-service/product/token-authentication-service/index.md

## Overview {#overview}

#### A Mastercard service that enables merchants to perform seamless cardholder authentication during checkout {#a-mastercard-service-that-enables-merchants-to-perform-seamless-cardholder-authentication-during-checkout}

Cardholders will be able to create payment passkeys with Mastercard and use those payment passkeys to authenticate with biometric authentication in remote commerce token transactions initiated from card on file or guest checkout, including Click to Pay. The biometric authentication mechanism is provided by their device's operating system such as fingerprint or face recognition.

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![User persona1](https://static.developer.mastercard.com/content/transaction-authentication-service/Images/icon_tas_1_passkey.svg)

###### Passkeys add security and convenience {#passkeys-add-security-and-convenience}

Mastercard's multi-factor authentication method leverages passkeys available on consumer devices. Consumers authenticate with biometric authentication that they use every day to unlock their devices
![User persona2](https://static.developer.mastercard.com/content/transaction-authentication-service/Images/icon_tas_2_checkout.svg)

###### Consistent experience across merchants {#consistent-experience-across-merchants}

Cardholders create a payment passkey with Mastercard for their Mastercard cards, and use that passkey across all merchants and checkout options (card on file or guest checkout including Click to Pay)
![User persona3](https://static.developer.mastercard.com/content/transaction-authentication-service/Images/icon_tas_3_standards.svg)

###### Leverages industry standards {#leverages-industry-standards}

Mastercard's implementation follows EMVco and FIDO standards to deliver a high level of security and privacy, and interoperability across consumer devices and merchant applications

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## Biometric authentication during checkout {#biometric-authentication-during-checkout}

Watch this video for an overview of the benefits and user experience provided through the Token Authentication Service

## How it works {#how-it-works}

##### Consumers can authenticate with their payment passkey at any merchant or digital wallet participating in Token Authentication Service {#consumers-can-authenticate-with-their-payment-passkey-at-any-merchant-or-digital-wallet-participating-in-token-authentication-service}

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**Step 1** : Consumers may be invited to create a payment passkey with Mastercard during or outside of a merchant checkout, or within the issuer application, and their identity is validated by their issuer during that process.

**Step 2** : Consumers may choose to use their payment passkey when paying with their Mastercard card at any participating merchant or digital wallet, as follows:
![User persona3](https://static.developer.mastercard.com/content/transaction-authentication-service/Images/img_tas_1_cardonfile_2x.webp)

##### Consumer selects a card on file {#consumer-selects-a-card-on-file}

The consumer's card is already stored on file or with Click to Pay. This card is already linked to their passkey.
![User persona3](https://static.developer.mastercard.com/content/transaction-authentication-service/Images/img_tas_2_faceid_2x.webp)

##### Consumer authenticates with passkey {#consumer-authenticates-with-passkey}

They use the authentication mechanism available on their device e.g., fingerprint.
![User persona3](https://static.developer.mastercard.com/content/transaction-authentication-service/Images/img_tas_3_checkout_2x.webp)

##### Checkout is complete {#checkout-is-complete}

Mastercard provides authentication results to the Issuer

## Why use it {#why-use-it}

##### Token Authentication Service is a scalable solution provided by Mastercard to authenticate cardholders with device biometrics wherever they pay online with their Mastercard {#token-authentication-service-is-a-scalable-solution-provided-by-mastercard-to-authenticate-cardholders-with-device-biometrics-wherever-they-pay-online-with-their-mastercard}

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Authentication service available as part of merchant or digital wallet's token implementation, reducing integration efforts to authenticate cardholders during the checkout
![User persona4](https://static.developer.mastercard.com/content/transaction-authentication-service/Images/icon_tas_4_merchant.svg)

##### Merchants {#merchants}

An authentication that minimizes friction during the checkout and is performed under the Mastercard Token Authentication Framework.
![User persona5](https://static.developer.mastercard.com/content/transaction-authentication-service/Images/icon_tas_4_issuer.svg)

##### Issuers {#issuers}

Improved transaction quality and ability to initiate the creation of Mastercard payment passkeys within their application.
![User persona6](https://static.developer.mastercard.com/content/transaction-authentication-service/Images/icon_tas_4_consumer.svg)

##### Consumers {#consumers}

A consistent and seamless authentication when they use their Mastercard card in an online checkout, regardless of how and where they choose to check out

## Use cases {#use-cases}

##### Token Authentication Service is currently available to authenticate cardholders in the following use cases. {#token-authentication-service-is-currently-available-to-authenticate-cardholders-in-the-following-use-cases}

![User persona7](https://static.developer.mastercard.com/content/transaction-authentication-service/Images/img_tas_4_scf_2x.webp)
CARD ON FILE

#### Secure Card on File {#secure-card-on-file}

Merchants implementing card on file tokenization using Secure Card on File specifications can request transaction authentication with payment passkeys during checkout.


[Learn more](https://developer.mastercard.com/mastercard-checkout-solutions/documentation/token-authentication/secure-card-on-file/by-mastercard/authentication-with-passkey/create-passkey/)
![User persona8](https://static.developer.mastercard.com/content/transaction-authentication-service/Images/img_tas_5_ctp_2x.webp)
GUEST CHECKOUT

#### Click to Pay {#click-to-pay}

Click to Pay merchants can request transaction authentication with payment passkeys during checkout for new and returning users.


[Learn more --- Mastercard checkout solutions](https://developer.mastercard.com/mastercard-checkout-solutions/documentation/token-authentication/click-to-pay/use-case1/)


[Learn more --- Unified checkout solutions](https://developer.mastercard.com/unified-checkout-solutions/documentation/token-authentication/tas_c2p/use-case1/)