Reference version

Expo SecureStore iconExpo SecureStore

一个提供在设备本地加密并安全存储键值对的方法的库。

Android
iOS
tvOS
Included in Expo Go
Bundled version:
~15.0.8

For the complete documentation index, see llms.txt. Use this Use this file to discover all available pages.

expo-secure-store 提供了一种在设备本地加密并安全存储键值对的方法。每个 Expo 项目都有各自独立的存储系统,无法访问其他 Expo 项目的存储。

底层平台可能会拒绝较大的负载。历史上,某些 iOS 版本会拒绝大约 2048 字节以上的值。Expo 不会强制限制,因此如果你计划存储非常大的字符串,请确保处理原生错误。

由于缺少 NSFaceIDUsageDescription 键,当可用生物识别认证时,Expo Go 中不支持 requireAuthentication 选项。

安装

Terminal
npx expo install expo-secure-store

If you are installing this in an existing React Native app, make sure to install expo in your project.

在 app config 中配置

如果你在项目中使用 config plugins(Continuous Native Generation (CNG)),可以使用其内置的 config plugin 来配置 expo-secure-store。该插件允许你配置一些无法在运行时设置、且需要重新构建新的应用二进制文件才会生效的属性。如果你的应用没有使用 CNG,那么你需要手动配置该库。

Example app.json with config plugin

app.json
{ "expo": { "plugins": [ [ "expo-secure-store", { "configureAndroidBackup": true, "faceIDPermission": "允许 $(PRODUCT_NAME) 访问你的 Face ID 生物识别数据。" } ] ] } }

Configurable properties

NameDefaultDescription
configureAndroidBackuptrue
Only for:
Android

一个布尔值,表示是否配置 Android 自动备份以便与 expo-secure-store 正常工作。了解更多

faceIDPermission"允许 $(PRODUCT_NAME) 访问你的 Face ID 生物识别数据。"
Only for:
iOS

用于设置 NSFaceIDUsageDescription 权限消息的字符串。

Are you using this library in an existing React Native app?

NSFaceIDUsageDescription 键添加到 Info.plist

Info.plist
<key>NSFaceIDUsageDescription</key> <string>允许 $(PRODUCT_NAME) 访问你的 Face ID 生物识别数据。</string>

平台值存储

Android

在 Android 上,值存储在 SharedPreferences 中,并使用 Android 的 Keystore 系统进行加密。

iOS

在 iOS 上,值通过 keychain serviceskSecClassGenericPassword 的形式存储。由于 iOS Keychain 的底层特性,使用 expo-secure-store 存储的数据在应用被卸载后,如果使用相同的 bundle ID 重新安装,数据仍会保留。 这是 iOS Keychain 系统的预期行为,在设计应用的数据处理方式时应考虑到这一点。iOS 还提供了额外选项,可以设置值的 kSecAttrAccessible 属性,用于控制该值何时可被读取。

数据持久性

expo-secure-store 的设计目标是在应用重启和更新之间提供持久的数据存储方案。然而,不应将其作为不可替代、关键数据的唯一真实来源。

  • 在 Android 上: 使用 expo-secure-store 保存的数据在应用卸载后不会被保留
  • 在 iOS 上: 如果应用使用相同的 bundle ID 重新安装,使用 expo-secure-store 保存的数据会在应用卸载后继续保留。这是由 iOS Keychain 管理已存储凭据的方式决定的。请记住,这并不能得到保证,你也不应依赖这一实现细节。

此外,任何通过将 requireAuthentication 选项设为 true 保护的数据,如果用户的生物识别设置发生变化,例如添加了新的指纹,都将变得无法访问。

免除加密提示

Apple App Store Connect 会提示你选择应用所实现的加密算法类型。这被称为 Export Compliance Information。在发布应用或提交 TestFlight 时会出现此提示。

使用 expo-secure-store 时,你可以在 app config 中将 ios.config.usesNonExemptEncryption 属性设置为 false

app.json
{ "expo": { "ios": { "config": { "usesNonExemptEncryption": false } %%placeholder-start%%... %%placeholder-end%% } } }

设置此属性会自动处理合规信息提示。

Android 自动备份

Android Auto Backup for Apps 会自动为目标平台为 Android 6.0(API level 23)或更高版本的应用备份用户数据。

Auto Backup 系统必须配置为排除 expo-secure-store 的共享首选项条目,因为在恢复备份后无法解密它们——应用在卸载时,其条目会从 Android Key Store 中删除。

如果你的应用没有任何自定义备份配置,expo-secure-store 会自动配置 Auto Backup 系统以忽略 expo-secure-store 数据。

如果你正在使用自己的 Auto Backup 配置,你应该在 sharedpref 域下排除 SecureStore,并在 config plugin 配置 中将 configureAndroidBackup 设置为 false

<!-- Android 12 及更高版本的 Auto Backup 配置 --> <data-extraction-rules> <cloud-backup> <include domain="sharedpref" path="."/> <exclude domain="sharedpref" path="SecureStore"/> </cloud-backup> <device-transfer> <include domain="sharedpref" path="."/> <exclude domain="sharedpref" path="SecureStore"/> </device-transfer> </data-extraction-rules>
<!-- Android 11 及更低版本的 Auto Backup 配置 --> <full-backup-content> <include domain="sharedpref" path="."/> <exclude domain="sharedpref" path="SecureStore"/> </full-backup-content>

用法

SecureStore
import { useState } from 'react'; import { Text, View, StyleSheet, TextInput, Button } from 'react-native'; import * as SecureStore from 'expo-secure-store'; async function save(key, value) { await SecureStore.setItemAsync(key, value); } async function getValueFor(key) { let result = await SecureStore.getItemAsync(key); if (result) { alert("🔐 Here's your value 🔐 \n" + result); } else { alert('该键下没有存储任何值。'); } } export default function App() { const [key, onChangeKey] = useState('Your key here'); const [value, onChangeValue] = useState('Your value here'); return ( <View style={styles.container}> <Text style={styles.paragraph}>保存一项内容,然后稍后取回!</Text> {%%placeholder-start%%Add some TextInput components... %%placeholder-end%%} <TextInput style={styles.textInput} clearTextOnFocus onChangeText={text => onChangeKey(text)} value={key} /> <TextInput style={styles.textInput} clearTextOnFocus onChangeText={text => onChangeValue(text)} value={value} /> {} <Button title="保存此键/值对" onPress={() => { save(key, value); onChangeKey('Your key here'); onChangeValue('Your value here'); }} /> <Text style={styles.paragraph}>🔐 输入你的键 🔐</Text> <TextInput style={styles.textInput} onSubmitEditing={event => { getValueFor(event.nativeEvent.text); }} placeholder="输入你想获取的值对应的键" /> </View> ); } const styles = StyleSheet.create({ container: { flex: 1, justifyContent: 'center', paddingTop: 10, backgroundColor: '#ecf0f1', padding: 8, }, paragraph: { marginTop: 34, margin: 24, fontSize: 18, fontWeight: 'bold', textAlign: 'center', }, textInput: { height: 35, borderColor: 'gray', borderWidth: 0.5, padding: 4, }, });

API

import * as SecureStore from 'expo-secure-store';

Constants

SecureStore.AFTER_FIRST_UNLOCK

Android
iOS
tvOS

Type: KeychainAccessibilityConstant

The data in the keychain item cannot be accessed after a restart until the device has been unlocked once by the user. This may be useful if you need to access the item when the phone is locked.

SecureStore.AFTER_FIRST_UNLOCK_THIS_DEVICE_ONLY

Android
iOS
tvOS

Type: KeychainAccessibilityConstant

Similar to AFTER_FIRST_UNLOCK, except the entry is not migrated to a new device when restoring from a backup.

Deprecated: Use an accessibility level that provides some user protection, such as AFTER_FIRST_UNLOCK.

SecureStore.ALWAYS

Android
iOS
tvOS

Type: KeychainAccessibilityConstant

The data in the keychain item can always be accessed regardless of whether the device is locked. This is the least secure option.

Deprecated: Use an accessibility level that provides some user protection, such as AFTER_FIRST_UNLOCK_THIS_DEVICE_ONLY.

SecureStore.ALWAYS_THIS_DEVICE_ONLY

Android
iOS
tvOS

Type: KeychainAccessibilityConstant

Similar to ALWAYS, except the entry is not migrated to a new device when restoring from a backup.

SecureStore.WHEN_PASSCODE_SET_THIS_DEVICE_ONLY

Android
iOS
tvOS

Type: KeychainAccessibilityConstant

Similar to WHEN_UNLOCKED_THIS_DEVICE_ONLY, except the user must have set a passcode in order to store an entry. If the user removes their passcode, the entry will be deleted.

SecureStore.WHEN_UNLOCKED

Android
iOS
tvOS

Type: KeychainAccessibilityConstant

The data in the keychain item can be accessed only while the device is unlocked by the user.

SecureStore.WHEN_UNLOCKED_THIS_DEVICE_ONLY

Android
iOS
tvOS

Type: KeychainAccessibilityConstant

Similar to WHEN_UNLOCKED, except the entry is not migrated to a new device when restoring from a backup.

Methods

SecureStore.canUseBiometricAuthentication()

Android
iOS

Checks if the value can be saved with requireAuthentication option enabled.

Returns:
boolean

true if the device supports biometric authentication and the enrolled method is sufficiently secure. Otherwise, returns false. Always returns false on tvOS.

SecureStore.deleteItemAsync(key, options)

Android
iOS
tvOS
ParameterTypeDescription
keystring

The key that was used to store the associated value.

options(optional)SecureStoreOptions

An SecureStoreOptions object.

Default:{}

Delete the value associated with the provided key.

Returns:
Promise<void>

A promise that rejects if the value can't be deleted.

SecureStore.getItem(key, options)

Android
iOS
tvOS
ParameterTypeDescription
keystring

The key that was used to store the associated value.

options(optional)SecureStoreOptions

An SecureStoreOptions object.

Default:{}

Synchronously reads the stored value associated with the provided key.

Note: This function blocks the JavaScript thread, so the application may not be interactive when reading a value with requireAuthentication option set to true until the user authenticates.

Returns:
string | null

Previously stored value. It resolves with null if there is no entry for the given key or if the key has been invalidated.

SecureStore.getItemAsync(key, options)

Android
iOS
tvOS
ParameterTypeDescription
keystring

The key that was used to store the associated value.

options(optional)SecureStoreOptions

An SecureStoreOptions object.

Default:{}

Reads the stored value associated with the provided key.

Returns:
Promise<string | null>

A promise that resolves to the previously stored value. It resolves with null if there is no entry for the given key or if the key has been invalidated. It rejects if an error occurs while retrieving the value.

Keys are invalidated by the system when biometrics change, such as adding a new fingerprint or changing the face profile used for face recognition. After a key has been invalidated, it becomes impossible to read its value. This only applies to values stored with requireAuthentication set to true.

SecureStore.isAvailableAsync()

Android
iOS
tvOS

Returns whether the SecureStore API is enabled on the current device. This does not check the app permissions.

Returns:
Promise<boolean>

Promise which fulfils with a boolean, indicating whether the SecureStore API is available on the current device. Currently, this resolves true on Android and iOS only.

SecureStore.setItem(key, value, options)

Android
iOS
tvOS
ParameterTypeDescription
keystring

The key to associate with the stored value. Keys may contain alphanumeric characters, ., -, and _.

valuestring

The value to store.

options(optional)SecureStoreOptions

An SecureStoreOptions object.

Default:{}

Stores a key–value pair synchronously.

Note: This function blocks the JavaScript thread, so the application may not be interactive when the requireAuthentication option is set to true until the user authenticates.

Returns:
void

SecureStore.setItemAsync(key, value, options)

Android
iOS
tvOS
ParameterTypeDescription
keystring

The key to associate with the stored value. Keys may contain alphanumeric characters, ., -, and _.

valuestring

The value to store.

options(optional)SecureStoreOptions

An SecureStoreOptions object.

Default:{}

Stores a key–value pair.

Returns:
Promise<void>

A promise that rejects if value cannot be stored on the device.

Types

KeychainAccessibilityConstant

Android
iOS
tvOS

Type: number

SecureStoreOptions

Android
iOS
tvOS
PropertyTypeDescription
accessGroup(optional)string
Only for:
iOS

Specifies the access group the stored entry belongs to.

authenticationPrompt(optional)string

Custom message displayed to the user while requireAuthentication option is turned on.

keychainAccessible(optional)KeychainAccessibilityConstant
Only for:
iOS

Specifies when the stored entry is accessible, using iOS's kSecAttrAccessible property.

Default:SecureStore.WHEN_UNLOCKED

See: Apple's documentation on keychain item accessibility.

keychainService(optional)string
  • Android: Equivalent of the public/private key pair Alias.
  • iOS: The item's service, equivalent to kSecAttrService.

If the item is set with the keychainService option, it will be required to later fetch the value.

requireAuthentication(optional)boolean

Option responsible for enabling the usage of the user authentication methods available on the device while accessing data stored in SecureStore.

  • Android: Equivalent to setUserAuthenticationRequired(true) (requires API 23).
  • iOS: Equivalent to biometryCurrentSet. Complete functionality is unlocked only with a freshly generated key - this would not work in tandem with the keychainService value used for the others non-authenticated operations.

This option works slightly differently across platforms: On Android, user authentication is required for all operations. On iOS, the user is prompted to authenticate only when reading or updating an existing value (not when creating a new one).

Warning: This option is not supported in Expo Go when biometric authentication is available due to a missing NSFaceIDUsageDescription. In release builds or when using continuous native generation, make sure to use the expo-secure-store config plugin.