Adding caps will not stop anyone to measure directly at the processor pins. And the device is tamper-evident, not resistant. Nothing is. The goal is to slower and make attack more expensive.
That's true, 'swhy I specified power only at the USB port. It would allow the tamper-evident feature to do its job, as only needing non-invasive monitoring would let someone try without being noticed. It really only needs to withstand attack long enough for its owner to notice it missing.
.... it's conceivable that a sufficiently creative attacker could do basically the same power analysis attack just by recording EMI picked up by the soundcard in the computer or via RF emissions from the device. (It's apparently quite easy to pick up noise from the trezor from across the screen with a radio receiver). People who've tried this have been frustrated by the extreme amount of noise put off by the screen and power regulators, but sufficiently advanced DSP may overcome it.
Hmm, I wonder if it's FCC class B certified. Seems unlikely if it's throwing out a noticeable amount of RFI, so maybe using more elaborate shielding and coupling to the detector would help passive monitoring succeed. Might try placing it near a machine with an old taiwanese ISA-bus soundblaster clone in it; those were great at picking up noise!
