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Comment by cortesoft | Hacker News Reader

I remember seeing a talk at RSA a couple of years ago about the plausibility of the "Italian Job" type attack, where they make all the lights green and cause everyone to crash.. they said that sort of thing was impossible because there is a mechanical switch that prevents both lights from being green at the same time.

So at least an attacker couldn't cause those sorts of accidents, even if they could totally mess up the system.

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This was true back in the mechanical era when a drum was used for control; you physically could not engage multiple directions as green at the same time. I do not believe this is the case now that control is done with software/firmware.

Example Controllers: http://www.mccain-inc.com/controllers.html

The controllers may be able to order it but the lights are supposed to be wired so it's impossible. E.g. grounding the green lights thorugh the cross direction green lights so you can't illuminate green in all directions at once. Or something along those lines.

edit: s/opposite/cross/

It would make good sense to harden it against failure, which can come in any form (software, mechanical, etc)

That's pretty good foresight by whoever designed them.

Not foresight. It was a limitation of the hardware at the time. It's also a relic of the past and no longer accurate as modern boards don't possess the same limitation.

>Not foresight. It was a limitation of the hardware at the time.

Nonsense. Even mechanically timed lights can be wired to illuminate any arbitrary set of lamp in either direction. The only difference between then and now is that back then you had to physically move wires, whereas now it's software switched.

Well, yeah. I phrased that poorly. I'm just saying there is very little chance the designers foresaw the possibilities of people hacking into the lights when they were transitioned into computer controlled. I imagine it was done because it reduced the chance of a bug in the hardware creating an ambiguous signal.

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