SecureStore for sensitive data in React Native - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ ui_behavior

intermediate

What happens when you try to retrieve a non-existent key from SecureStore?

Consider this React Native code snippet using SecureStore to get a value for a key that was never saved. What will be the output?

React Native

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

async function getValue() {
  const result = await SecureStore.getItemAsync('missingKey');
  console.log(result);
}

getValue();

A Empty string ('')

B undefined

C Throws an error

D null

💡 Hint

Think about what SecureStore returns when the key does not exist.

SecureStore.getItemAsync returns null if the key is not found. It does not throw an error or return undefined or empty string.

❓ lifecycle

intermediate

When should you clear sensitive data from SecureStore in a React Native app?

You store a user's authentication token in SecureStore. When is the best time to remove this token to keep the app secure?

A When the app goes to background

B When the app is closed by the user

C When the user logs out

D Never remove it to keep user logged in

💡 Hint

Think about user control and security best practices.

Sensitive data like auth tokens should be removed when the user logs out to prevent unauthorized access. Closing or backgrounding the app does not guarantee security.

📝 Syntax

advanced

Which code snippet correctly saves and retrieves a password securely using SecureStore?

Choose the option that correctly saves a password and then retrieves it asynchronously using SecureStore in React Native.

A

await SecureStore.setItemAsync('password', 'myPass123');
const pass = await SecureStore.getItemAsync('password');
console.log(pass);

B

SecureStore.setItem('password', 'myPass123');
const pass = SecureStore.getItem('password');
console.log(pass);

C

await SecureStore.save('password', 'myPass123');
const pass = await SecureStore.load('password');
console.log(pass);

D

SecureStore.setItemAsync('password', 'myPass123');
const pass = SecureStore.getItemAsync('password');
console.log(pass);

💡 Hint

Remember the exact method names and that these are async functions.

The correct methods are setItemAsync and getItemAsync, both returning promises that must be awaited. Option A uses these correctly. Option A uses wrong method names and no await. Option A uses non-existent methods. Option A misses await on calls.

🔧 Debug

advanced

Why does this SecureStore code fail to save data?

Identify the reason this code does not save the data as expected.

React Native

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

function saveData() {
  SecureStore.setItemAsync('token', 'abc123');
}
saveData();

A Wrong method name, should be saveItemAsync

B Missing await before SecureStore.setItemAsync call

C SecureStore requires a callback, not a promise

D Key 'token' is reserved and cannot be used

💡 Hint

Check how async functions should be handled.

SecureStore.setItemAsync returns a promise. Without await or then, the function may not complete before the app continues, causing unexpected behavior. The method name is correct, no callbacks needed, and keys are not reserved.

🧠 Conceptual

expert

What is the main security advantage of using SecureStore over AsyncStorage for sensitive data?

Choose the best explanation for why SecureStore is preferred for storing sensitive information like passwords or tokens.

A SecureStore encrypts data and stores it in the device's secure hardware-backed storage, while AsyncStorage stores data unencrypted in plain text.

B SecureStore automatically backs up data to the cloud, AsyncStorage does not.

C SecureStore is faster than AsyncStorage for large data sets.

D SecureStore allows data sharing between apps, AsyncStorage does not.

💡 Hint

Think about data protection and encryption.

SecureStore uses the device's secure enclave or keystore to encrypt and protect data, making it much safer for sensitive info. AsyncStorage stores data as plain text files, which can be accessed if the device is compromised.