Here are some best practices for securely storing and protecting private API keys in Android applications:
Use the Android Keystore system to store cryptographic keys in a secure container that makes them difficult to extract from the device[1][4]. The keystore system prevents key material from entering the app process and can bind keys to the device's secure hardware like the Trusted Execution Environment (TEE) or Secure Element (SE)[4].
Generate a public/private RSA key pair using the Android Keystore API. Store the private key securely in the keystore and use it to encrypt an AES symmetric key. The AES key is then used to encrypt the API keys before storing them[1]. When the app needs the API keys, it retrieves the encrypted AES key from storage, has the keystore decrypt it with the private RSA key, and then uses the AES key to decrypt the API keys.
Never store API keys directly in source code, shared preferences, or other insecure locations. Obfuscation and encryption are not sufficient protection[2].
Consider storing API keys on your own secure server instead of in the app. Have the app send requests needing the keys through your server, so the keys never leave the server[2]. This adds l...
