1# Canceling User Authentication 2 3 4This topic walks you through the process of canceling an authentication in process. 5 6 7## Available APIs 8 9For details about the parameters, return value, and error codes, see [cancel](../../reference/apis-user-authentication-kit/js-apis-useriam-userauth.md#cancel10). 10 11This topic describes only the API for canceling authentication. For details about the APIs for initiating authentication, see [Initiating Authentication](start-authentication.md) and [User Authentication](../../reference/apis-user-authentication-kit/js-apis-useriam-userauth.md). 12 13| API| Description| 14| -------- | -------- | 15| cancel(): void | Cancels this user authentication.| 16 17 18## How to Develop 19 201. Check that the application has the ohos.permission.ACCESS_BIOMETRIC permission. For details about how to request permissions, see [Requesting Permissions](prerequisites.md#requesting-permissions). 21 222. Set [AuthParam](../../reference/apis-user-authentication-kit/js-apis-useriam-userauth.md#authparam10) (including the challenge value, [UserAuthType](../../reference/apis-user-authentication-kit/js-apis-useriam-userauth.md#userauthtype8), and [AuthTrustLevel](../../reference/apis-user-authentication-kit/js-apis-useriam-userauth.md#authtrustlevel8)), obtain a [UserAuthInstance](../../reference/apis-user-authentication-kit/js-apis-useriam-userauth.md#userauthinstance10) instance, and call [UserAuthInstance.start](../../reference/apis-user-authentication-kit/js-apis-useriam-userauth.md#start10) to start authentication. 23 For details, see [Initiating Authentication](start-authentication.md). 24 253. Use [UserAuthInstance.cancel](../../reference/apis-user-authentication-kit/js-apis-useriam-userauth.md#cancel10) with the **UserAuthInstance** instance that has initiated the authentication to cancel the authentication. 26 27Example: Initiate the facial and lock screen password authentication with the authentication trust level greater than or equal to ATL3 and cancel it. 28 29```ts 30import { BusinessError } from '@kit.BasicServicesKit'; 31import { userAuth } from '@kit.UserAuthenticationKit'; 32 33const authParam: userAuth.AuthParam = { 34 challenge: new Uint8Array([49, 49, 49, 49, 49, 49]), 35 authType: [userAuth.UserAuthType.PIN, userAuth.UserAuthType.FACE], 36 authTrustLevel: userAuth.AuthTrustLevel.ATL3, 37}; 38const widgetParam: userAuth.WidgetParam = { 39 title: 'Verify identity', 40}; 41try { 42 // Obtain a UserAuthInstance object. 43 let userAuthInstance = userAuth.getUserAuthInstance(authParam, widgetParam); 44 console.log('get userAuth instance success'); 45 // Start user authentication. 46 userAuthInstance.start(); 47 console.log('auth start success'); 48 // Cancel the authentication. 49 userAuthInstance.cancel(); 50 console.log('auth cancel success'); 51} catch (error) { 52 const err: BusinessError = error as BusinessError; 53 console.error(`auth catch error. Code is ${err?.code}, message is ${err?.message}`); 54} 55``` 56