John Gilmore writes:
> What are you guys talking about? Differential power analysis doesn't
> require any physical attack, nor does it deal with voltage
> variations. (You are probably thinking of Shamir's fault-injection
You can't do differential power analysis if you supply power
photonically to an encapsulated unit. Power dissipated gets averaged
out over time so you can't just monitor the temperature.
> attacks.) Differential power analysis measures the current
> consumption of the part as it operates, completely outside the device.
1) A self contained, sealed unit is immune to this
2) What prevents us from measuring the power & fill out lacunes a la
resistance heating? The unit would then show constant dissipation
regardless of which computation it performs.
> It uses statistical techniques to confirm or reject hypotheses about
> the key values being operated on in the final rounds of encryption
> algorithms. Paul Kocher's team has developed some countermeasures,
> see the end of the technical discussion linked from:
>
> http://www.cryptography.com/dpa/index.html
>
> John
