> They addressed it by saying that they used secure enclaves
The problem with using TEEs (Trusted Execution Environments) is all the trust that's involved. Unless you inspect the hardware itself, you don't know if it's been backdoored; and there is open source software that has been used to extract private keys from "unmodified" secure enclaves. So there's just no way to know the hardware is really doing what its operators promise it's doing.