Re:Creating a bespoke data diode for air‑gapped networks
by tonyarkles on Wednesday January 07, 2026 @11:12AM
(#46528105)
> In the past I have worked in defence, for highly sensitive stuff they wouldn't even allow a common ground between two networks.
I actually agree very much with this. If you're looking for strong assurance that there is no possible back-channel, devices like optocouplers help significantly. It's not hard for me to think of a way to surreptitiously send data backwards through a common ground, or normal silicon diode, or a magnetic coupler like an Ethernet transformer, but optoisolators make it significantly more challenging.
In the past I have worked in defence, for highly sensitive stuff they wouldn't even allow a common ground between two networks.
That's why I chose an option iolsator, it ensures the two devices are electrically isolated.
It's overkill for this application, but I wanted to set something up right, and if I ever have another project like this that needs to be more secure, it's ready to go.