I have no reason to believe this is true. Side channel attacks on QKD have been very effective, which is a strong indication that the ability to trust your hard

I have no reason to believe this is true. Side channel attacks on QKD have been very effective, which is a strong indication that the ability to trust your hardware is essential to the functioning of these systems. You’re proposing a model where one cannot trust their hardware, and I see no evidence that modern QKD systems have been hardened against that attack. PS I’ve worked a lot on cryptographic backdoors in the non-QKD setting but I don’t work on QKD.