With passive RFID you only need to eavesdrop on the communication link and this can be done from hundreds of feet away.
I have passive RFID for access to my house and my key fob has to be within about four inches of the reader for it to pick it up. I don't see how someone hundereds of feet away is going to be able to read it.
Doug
All it takes is a directional antenna and a sensitive receiver. There's no black magic, only straightforward principles that anyone with minimal electronics know-how can implement. It was documented a couple of years ago and was discussed here at the time. How strong do you think the radio signals sent from those Mars landers are?
At minimum, RF needs rolling codes to be secure. Almost all other schemes are easily compromised.
That's a bit misleading. You'd need a means to record and retransmit the signal. The fact is all but the exceptional thief have no such hardware and are not capable of using it. If we were talking about high security, government installations Mr. Houston's concerns would have a measure of validity. However, such installations are normally protected by multiple security layers (something you have plus something you know). An RFID system might be one layer. The holder has to enter a PIN after using his card. In many high security locations a live person also watches. This newsgroup is about *home* automation. It's not about LANL or ORNL.
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