> If you want your app to be fully end-to-end, you can use the lower level > unlock mechanisms, which are all end-to-end compliant

So if I want to use the SDK in a "fully" end-to-end secure way, I first need to implement by myself a secure way to transmit the user root secret (the unlock key) between the user's devices, and make sure this key is always accessible so that users don't loose access to their data. This doesn't seem like an easy task...