Expo Native Cryptography Modules

Expo Native Cryptography Modules

Expo provides several modules that make cryptography accessible and performant in your React Native applications. The expo-crypto module is the primary one, offering a JavaScript interface to the native cryptographic APIs of both iOS and Android. This gives you the speed of native code with the convenience of a JavaScript API.

The expo-crypto module supports several common cryptographic operations. You can generate random UUIDs, create cryptographic digests using SHA-1, SHA-256, SHA-384, and SHA-512, and generate random bytes. These operations are performed using the platform's native cryptographic libraries, making them much faster than JavaScript implementations. The module is easy to use and requires no native configuration.

For secure storage of cryptographic keys and sensitive data, Expo provides the expo-secure-store module. This stores data in the iOS Keychain on iOS and the Android Keystore on Android. Data stored in SecureStore is encrypted at rest and can only be accessed by your app. This is the recommended way to store API tokens, encryption keys, and other sensitive information.

If you need more advanced cryptographic operations, you can combine Expo's modules with a custom native module. For example, you can use expo-secure-store to store a private key, and write a custom native module that uses the key to perform digital signatures or decrypt data. This approach gives you both the security of native key storage and the performance of native cryptographic operations.