1# @ohos.file.keyManager (User Key Management) (System API) 2<!--Kit: Core File Kit--> 3<!--Subsystem: FileManagement--> 4<!--Owner: @wang_zhangjun; @zhuangzhuang--> 5<!--Designer: @wang_zhangjun; @zhuangzhuang; @renguang1116--> 6<!--Tester: @liuhonggang123; @yue-ye2; @juxiaopang--> 7<!--Adviser: @foryourself--> 8 9This module provides common functions related to user key management, including user key uninstallation. 10 11> **NOTE** 12> 13> - The initial APIs of this module are supported since API version 15. Newly added APIs will be marked with a superscript to indicate their earliest API version. 14> - This topic describes only the system APIs provided by the module. 15 16## Modules to Import 17 18```ts 19import { keyManager } from "@kit.CoreFileKit"; 20``` 21 22## keyManager.deactivateUserKey 23 24deactivateUserKey(userId: number):void 25 26When the screen is locked, the specified user key is uninstalled synchronously. **(Currently, this API is available only to lock screen applications.)** 27 28**Required permission**: ohos.permission.STORAGE_MANAGER_CRYPT 29 30**System capability**: SystemCapability.FileManagement.StorageService.Encryption 31 32**System API**: This is a system API. 33 34**Parameters** 35 36 | Name | Type | Mandatory| Description| 37 | ---------- | ------ | ---- | ---- | 38 | userId | number | Yes | User ID. This parameter specifies the user who currently logs in to the lock screen application.| 39 40**Error codes** 41 42For details about the error codes, see [File Management Error Codes](errorcode-filemanagement.md). 43 44| ID| Error Message| 45| -------- | -------- | 46| 201 | Permission verification failed. | 47| 202 | The caller is not a system application. | 48| 401 | The input parameter is invalid. Possible causes: Mandatory parameters are left unspecified; Or input parameter has type different from the type the interface requires. | 49| 13600001 | IPC error. | 50| 13600008 | No such object. Possible causes: Cannot find user key for the specified user. | 51| 13600009 | User ID out of range. Possible causes: input parameter userId < 100 or userId > 10736. | 52 53**Example**: 54 55 ```ts 56 import { keyManager } from "@kit.CoreFileKit"; 57 import { BusinessError } from '@ohos.base'; 58 let userId: number = 100; 59 try { 60 keyManager.deactivateUserKey(userId); 61 console.info("deactivateUserKey success"); 62 } catch (err) { 63 let error: BusinessError = err as BusinessError; 64 console.error("deactivateUserKey failed with error:" + JSON.stringify(error)); 65 } 66 ``` 67