[Home](./index.md) > [@digitalpersona/authentication](./authentication.md) > [SmartCardAuth](./authentication.smartcardauth.md) > [authenticate](./authentication.smartcardauth.authenticate.md) ## SmartCardAuth.authenticate() method Authenticates the user using a smartcard. Signature: ```typescript authenticate(identity: User | JSONWebToken, cardData: string): Promise; ``` ## Parameters | Parameter | Type | Description | | --- | --- | --- | | identity | User | JSONWebToken | a or a JSON Web Token. | | cardData | string | card authentication data received from the card using a PIN. | Returns: `Promise` a promise to return a JSON Web Token containing a claim (`crd`) showing the fact a smartcard was used. Will reject if authentication fails. ## Remarks If the `identity` parameter is a user name, a new token will be created. If the `identity` parameter is a JSON Web Token, an updated token will be returned.