Encrypting sensivite data in React Native and Expo

I am recently involved in a React Native project with security concerns like yours. Security is not an easy issue and I am not an expert, but this is what we did.

We used react-native-aes-encryption for encryption and hashing, react-native-rsa for generating public/private key pairs. In order to use these libraries properly, you better need to know basic cryptography concepts.

We used react-native-keychain to read/write data from keychain. Keychain is the way to go if you want to store some small sensitive data. It has been used in all Apple OS's in order to keep your passwords safe. That said this component is not working as seamless as expected on the Android side if you want to build your app for both platforms.

Other than that I have no idea about expo. I hope these libraries work for you as well.

Expo now has SecureStore, which stores encrypted data.

Details: https://docs.expo.io/versions/latest/sdk/securestore