Also, things like DVB tuners are not exactly cheap enough to be integrated into many devices (though FM receivers, which may be used in the future, are).
If the payment terminal used an SPV-like technology, the attacker would have to have a tremendous amount of computing power. This attack is not feasible, especially considering the relatively small reward of fooling an ATM or a parking meter.
Are there any such chips other than the Broadcom chip that was announced last year?
[1] http://www.broadcom.com/press/release.php?id=s736006 [2] http://www.digitaltvnews.net/?p=24266
In this case, there's a single communications channel that could be spoofed by anyone with a transmitter powerful enough to drown out the legitimate signal.
You could stop sending new blocks, but that would alarm the endpoint because it will be stuck at block 100 (in our example).
The Proof-of-work scheme is pretty innovative.
As noted in the article (under the "technology" page), signing is planned but not yet implemented.
> Also, things like DVB tuners are not exactly cheap enough to be integrated into many devices (though FM receivers, which may be used in the future, are).
What kind of devices are you thinking of? It seems to me that the most useful applications of this system would be for vending machines. A $10 DVB-T demodulator (at scale they can be had much cheaper than that) is a rounding error in the cost of those devices.