41–50 of 86 posts
Those wires are certainly long enough to be antennas.
A "diode" is not an air gap. If there is any flow in either direction, you don't have an air gap. This isn't hard to understand.
yes, but if your adversary is capable of exploiting a one-way diode to RCE, you might as well just give up.
I would like to know how they come to such a conclusion as this is either a misunderstanding or an AI solution. The opto isolator does not maintain the air gap. It only provides galvanic isolation which is likely unnecessary in this situation.
Galvanic isolation is useful in situations where you want to isolate circuits from electrical potential issues (ground loops and so on) or isolation from noise and faults.
> An opto coupler, also known as an opto isolator, allows an electrical signal to pass from one device to another using light, preventing direct electrical connection. *This ensures data flows in a single direction, maintaining the integrity of the air gap.* I would like to know how they come to such a conclusion as this is either a misunderstanding or an AI solution. The opto isolator does not maintain the air gap.…
You can either just block packets in one direction, or you can add a small amount of risk and allow UDP and TCP with zero payload in one direction. That would allow you to reliably stream in one direction and request from either direction, albeit with a slightly exploitable channel (timing, reliability or the space of values allowed in the protocol).
You already have to trust the RPI hardware to not enable WiFi on either side, so why not trust a router?
Why not use optical ethernet as ‘real’ cross domain solutions do? Probably cheaper if you don’t mind eBay, and gives you an easy upgrade path to 10Gbps or more in future. Two port NIC on the low side. Port 2 has its TX side connected to Port 1’s RX, just so the port will see a carrier and show link up. Port 1 TX goes to the high side machine’s RX, with TX left open. From here, you have a whole ton of protocol options…
Could've used a speaker and microphone with an appropriate noise-resistant digital encoding.
That has to be abysmal bandwidth, right? How much data can you practically transfer that way?
It may be possible to increase the bandwidth by increasing the sample rate on both ends, but this quickly leaves the realm of consumer audio equipment (and consumer pricing). At some point you'd exceed the reasonable frequency responses for each device, as well as the medium. I imagine that air attenuates ultrasonic frequencies more than lower ones, but that's just a guess.
Earlier quoted context omitted.
All speakers can act as microphones. But due to physics you'd have a much harder time turning a photodiode into a light emitting one (the physics means you only can get IR out and the LED can't receive anything that way).
> the physics means you only can get IR out and the LED can't receive anything that way Gut feeling tells me there is a way, if you use way more power than normal for this :). Much like with making speakers receive sound (you need to amplify the received signal afterwards) and making microphones produce it. But it doesn't really matter whether or not you can reverse the analog signal flow, if the digital side treats…
The threat model where you use a data diode presumes an adversary might totally compromise the sending side - the guarantee you're trying to add is that whatever malware they push down the line has no ability to exfiltrate data regardless of how compromised it is.
> An opto coupler, also known as an opto isolator, allows an electrical signal to pass from one device to another using light, preventing direct electrical connection. *This ensures data flows in a single direction, maintaining the integrity of the air gap.* I would like to know how they come to such a conclusion as this is either a misunderstanding or an AI solution. The opto isolator does not maintain the air gap.…