HIPAA doesn't care about the logistics of whether or not the intermediary can/cannot decrypt the data. If the intermediary touches the data and it's not exempt by the conduit exception, then there has to be a BAA in place. It's why even though FaceTime hypothetically has E2E encryption and Apple claims to not have the capability to decrypt the data, it's still inappropriate to use for patient-doctor communication due to the lack of that BAA being in place.