HomeGuidesReferenceLearn

Reference version

ArchiveExpo SnackDiscord and ForumsNewsletter

Expo SecureStore iconExpo SecureStore

GitHub

npm

A library that provides a way to encrypt and securely store key-value pairs locally on the device.

Android
iOS

expo-secure-store provides a way to encrypt and securely store key–value pairs locally on the device. Each Expo project has a separate storage system and has no access to the storage of other Expo projects.

Size limit for a value is 2048 bytes. An attempt to store larger values may fail. Currently, we print a warning when the limit is reached, however, in a future SDK version an error might be thrown.

The requireAuthentication option is not supported in Expo Go when biometric authentication is available due to a missing NSFaceIDUsageDescription key.

This API is not compatible with devices running Android 5 or lower.

Installation

Terminal
npx expo install expo-secure-store

If you're installing this in a bare React Native app, you should also follow these additional installation instructions.

Configuration in app.json/app.config.js

You can configure expo-secure-store using its built-in config plugin if you use config plugins in your project (EAS Build or npx expo run:[android|ios]). The plugin allows you to configure various properties that cannot be set at runtime and require building a new app binary to take effect.

Example app.json with config plugin

app.json
{
  "expo": {
    "plugins": [
      [
        "expo-secure-store",
        {
          "faceIDPermission": "Allow $(PRODUCT_NAME) to access your Face ID biometric data."
        }
      ]
    ]
  }
}

Configurable properties

NameDefaultDescription
faceIDPermission"Allow $(PRODUCT_NAME) to access your Face ID biometric data."
Only for:
iOS

A string to set the NSFaceIDUsageDescription permission message.

Are you using this library in a bare React Native app?

Add NSFaceIDUsageDescription key to your Info.plist:

Platform value storage

Android

On Android, values are stored in SharedPreferences, encrypted with Android's Keystore system.

iOS

For iOS standalone apps, data stored with expo-secure-store can persist across app installs.

On iOS, values are stored using the keychain services as kSecClassGenericPassword. iOS has the additional option of being able to set the value's kSecAttrAccessible attribute, which controls when the value is available to be fetched.

Exempting encryption prompt

Apple App Store Connect prompts you to select the type of encryption algorithm your app implements. This is known as Export Compliance Information. It is asked when publishing the app or submitting for TestFlight.

When using expo-secure-store, you can set the ios.config.usesNonExemptEncryption property to false in the app config:

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

Setting this property automatically handles the compliance information prompt.

Usage

SecureStore
import * as React 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('No values stored under that key.');
  }
}

export default function App() {
  const [key, onChangeKey] = React.useState('Your key here');
  const [value, onChangeValue] = React.useState('Your value here');

  return (
    <View style={styles.container}>
      <Text style={styles.paragraph}>Save an item, and grab it later!</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="Save this key/value pair"
        onPress={() => {
          save(key, value);
          onChangeKey('Your key here');
          onChangeValue('Your value here');
        }}
      />
      <Text style={styles.paragraph}>🔐 Enter your key 🔐</Text>
      <TextInput
        style={styles.textInput}
        onSubmitEditing={event => {
          getValueFor(event.nativeEvent.text);
        }}
        placeholder="Enter the key for the value you want to get"
      />
    </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

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

Type: KeychainAccessibilityConstant


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

SecureStore.ALWAYS

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.

SecureStore.ALWAYS_THIS_DEVICE_ONLY

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

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

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

Type: KeychainAccessibilityConstant


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

Methods

SecureStore.canUseBiometricAuthentication()

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.

SecureStore.deleteItemAsync(key, options)

NameTypeDescription
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 will reject if the value couldn't be deleted.

SecureStore.getItem(key, options)

NameTypeDescription
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 will return null if there is no entry for the given key or if the key has been invalidated.

SecureStore.getItemAsync(key, options)

NameTypeDescription
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 will return null if there is no entry for the given key or if the key has been invalidated. It will reject 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()

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

Returns:

Promise<boolean>

Promise which fulfils witch 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)

NameTypeDescription
keystring

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

valuestring

The value to store. Size limit is 2048 bytes.

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)

NameTypeDescription
keystring

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

valuestring

The value to store. Size limit is 2048 bytes.

options
(optional)
SecureStoreOptions

An SecureStoreOptions object.

Default: {}

Stores a key–value pair.

Returns:

Promise<void>

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

Types

KeychainAccessibilityConstant

Type: number

SecureStoreOptions

NameTypeDescription
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.

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.