Possible magnetic vulnerability

[materribile]

Sirs and Mesdames,

After looking over your project info, I see what might be a vulnerability to outside influence, and have joined to tell you.  It's possible you've addressed this already; if so, please excuse the interruption.

Your noise source is driven by a higher voltage generated by a switching supply.  If the inductor in that supply is anything but air-core, it is potentially vulnerable to saturation by a constant or very-low-frequency -magnetic- field.  Your copper shielding will have a very limited effect on such a field.

I don't know whether it would be possible to influence the RNG in a covert way, or whether the effect would always be detected, but I wanted to bring this possibility to your attention, and for that purpose I have registered here.

If an air-core inductor will not serve, and cannot be isolated from VLF interference, you might consider replacing the switching supply with a voltage multiplier.