Need help with example HW AES

Embedded Security Side Channel Power Analysis
1

Hi there,
I download the example:

SAKURA-G Traces, AES at 1.5MHz, Measured with PicoScope 6403D (Asyncronously)

4000 traces, sampled at 156MS/s using LNA on SAKURAG: [sakurag-picoscope6403d-4000.zip]

from URL:
https://app.assembla.com/spaces/chipwhisperer/wiki/Example_Captures

I used the CPA attack with the model “LastroundStateDiff” and I successfully got the key:
2b 7e 15 16 28 ae d2 a6 ab f7 15 88 09 cf 4f 3c
The key was highlited red in ChipWhisperer

But it’s not AES key, the true AES key is:
00 01 02 03 04 05 06 07 08 F7 15 88 09 CF 4F 3C
it’s wrote in the file “2014.02.03-16.05.00_knownkey.npy”

also 2b 7e 15 16 28 ae d2 a6 ab f7 15 88 09 cf 4f 3c - it’s not the round key.

What exactly did I got?
And how to get the real AES key from this ?

2

Hi,

Yup, you’re correct that the two keys don’t match up. The 2b 7e ... key is the default one used in most of ChipWhisperer, so it’s highlighted in red by default in Analyzer, but that doesn’t mean that it’s the key actually found by the attack. Instead, the actual key you’re recovering from the attack is the one with the lowest PGE (top row of the results table in Analyzer).

Alex