momurda last edited by
Im studying for my Security + a bit these days.
Come across NFC and i start reading at nearfieldcommunication.org
I am wondering how the 10cm conversations are secured. Couldnt someone just amplify the interrogator radio signal to get the same signal strength that would appear at 10cm to appear at say 1m? Just newbie question, i surei i find the answer if i read more.
You can boost the power and change the antenna, but the fundamental signally type is very difficult to make go any distance. So you'd quickly be pushing crazy amounts of power for each additional cm.
Most of this tech tops out with theoretical limits around 20cm. So even if you weren't trying to be sneaky and had lots of obvious tech that people could see, getting from the 20cm limit to the 100cm that you are talking about would be possibly beyond the limits of human technology currently.
Think of NFC radio a bit like gears. When they are near, the cogs touch and the one wheel turns the other. Once you get past 20cm, the teeth of the gears aren't touching each other any more. So for one gear to turn the other you'd like need it to push enough air to make the other one want to turn. Theoretically possible, but it'll use an insane amount of power to do it.
momurda last edited by momurda
You would need 100x power for 10x the range(like in my example) if i remember radio wave math correctly. And that wouldnt help you receive farther from a regular rfid chip either.