Basically none these days. But therein lies the problem. The actors can't be trusted. In part because the state-actors in which they reside can't be trusted

Basically none these days. But therein lies the problem. The actors can't be trusted. In part because the state-actors in which they reside can't be trusted and they can (and do) issue gag-orders to shove backdoors down their throat. But the problem with backdoors has always been that other people will likely eventually figure out how to use them too. If you can't audit the microcode, you have a massive gaping security problem.