|As of August 2020 the site you are on (wiki.newae.com) is deprecated, and content is now at rtfm.newae.com.|
→13th Round Key
# Imports for AES256 Attack
AES128_8bit import getHWfrom chipwhisperer.analyzer.models.aes.funcs import sbox, inv_sbox, inv_shiftrows, inv_mixcolumns, inv_subbytes
You can look back at the C code of the AES-256 decryption to see how this is implementing the decryption code. Note that because of the Inverse MixColumns operation, we need the entire input ciphertext -- otherwise, we would only need to operate on one byte of the ciphertext.
# Add the above function to your custom script file.
# Change the <code>setAnalysisAlgorithm</code> in the script to use your custom functions by making the following call:
# As we did in the 14th round attack, reducing the point range can speed up the attack. For example, to use a smaller range of points, try changing the <code>setPointRange()</code> function call to
>>> from chipwhisperer.analyzer.models.aes.funcs import shiftrows,mixcolumns
>>> knownkey = [0xC6, 0xBD, 0x4E, 0x50, 0xAB, 0xCA, 0x75, 0x77, 0x79, 0x87, 0x96, 0xCA, 0x1C, 0x7F, 0xC5, 0x82]
>>> key = shiftrows(knownkey)