So your NDA allows you to acknowledge that a side-channel cryptographic compromise is possible but not give any details? That's a really funny NDA. I call bullshit.
Since I have executed one with my employer yes I do.
For example if you asked me directly if such an attack was possible I cannot answer you due to my NDA even though I have personal experience with the matter. You seem really eager to answer that it is though.
All of the NDAs I have signed have never said anything like "you can't say how, but you can say that we pulled it off". In fact most of the NDAs I've signed have been along the lines of "you don't talk about Fight Club".
Can we deduce that you are willing to violate your NDA to write that you have observed such an attack or that you never executed an NDA regarding the specific attack? Yes.
Or did you violate it to tell me 'yes'?