How Can I Use the Android KeyStore to securely store arbitrary strings?

Question

I would like to be able securely store some sensitive strings in the Android KeyStore. I get the strings from the server but I have a use case which requires me to persist t

Answer 1

You may have noticed that there are problems handling different API levels with the Android Keystore.

Scytale is an open source library that provides a convenient wrapper around the Android Keystore so that you don't have write boiler plate and can dive straight into enryption/decryption.

Sample code:

// Create and save key
Store store = new Store(getApplicationContext());
if (!store.hasKey("test")) {
   SecretKey key = store.generateSymmetricKey("test", null);
}
...

// Get key
SecretKey key = store.getSymmetricKey("test", null);

// Encrypt/Decrypt data
Crypto crypto = new Crypto(Options.TRANSFORMATION_SYMMETRIC);
String text = "Sample text";

String encryptedData = crypto.encrypt(text, key);
Log.i("Scytale", "Encrypted data: " + encryptedData);

String decryptedData = crypto.decrypt(encryptedData, key);
Log.i("Scytale", "Decrypted data: " + decryptedData);