Proof of FPGA is not required, we know that FPGA can do it if someone programs them to. However their acceleration factor is not that big and it's highly unlikely to find thousands of them.
ASIC = I don't know. But even at a 500x acceleration factor compared to a GPU (say a 3 MHs GPU / 1.5 GHs ASIC) it'd take HUNDREDS of them to pull stuff like 800-900 gigahash. FPGAs even more so because their acceleration is much closer to GPUs. I saw the link the guy gave as "x11 fpga program" which was bullshit, but hashpower is hashpower and it was tremendous.
If I were the NSA I'd make sure to have hardware ASICs for every single algorithm out there. If I want to break a wallet, or control a crypto network, I won't do it with GPUs. The budget for acquiring such equipment is pretty low for their standards. They could control 51% of bitcoin right now if they spent something like 100-200mn in ASIC for SHA256 and destroy bitcoin. Even 1 bn budget for ASIC hardware is peanuts compared to protecting the hegemony of the dollar.
I believe they have the theoretical possibility of overriding every single POW network out there with 51% but a POS coin would remain resilient from a POW attack as it works through POS staking. So they would have a mess at their hand with an anonymous coin that remains resilient. So their hardware would be useless for 51% override. But it wouldn't be useless in the coin generation phase (POW). That's where I suspect they put their hardware on and started mining with that insane hashrate to get a 51% stake and control the future of the coin. If they didn't manage that, they'll manage it through buying a few more to get there.
The absence of that hashrate from every other x11 coin is a huge indicator. The fact that, suddenly, 900gh of x11 hashpower appeared out of nowhere just to mine XC, doesn't "just" happen.
Government agencies like the NSA have a lot to gain from ensuring DRK is a major success... Governments have more to hide than the average punter out there, it would make funding their wars offshore so much more efficient...
except they can only afford that stuff because of money printing and they cant print crypto.