{{Warningbox|This tutorial is an add-on to [[Tutorial A5 Breaking AES-256 Bootloader]]has been updated for ChipWhisperer 5 release. It continues working on If you are using 4.x.x or 3.x.x see the same firmware, showing how to obtain the hidden IV and signature "V4" or "V3" link in the bootloader. '''It is not possible to do this bonus tutorial without first completing the regular tutorial''', so please finish Tutorial A5 firstsidebar.}}
''This {{Infobox tutorial is under construction! Check back in a few days.''|name = A5: Breaking AES-256 Bootloader|image = |caption = |software versions =|capture hardware = CW-Lite, CW-Lite 2-Part, CW-Pro|Target Device = |Target Architecture = XMEGA/Arm|Hardware Crypto = No|Purchase Hardware = }}
= Background =<!-- To edit this, edit Template:Tutorial_boilerplate -->== AES in CBC Mode ==* Repeat of theory from tutorial== The IV ==* Suggest some ideas== The Signature ==* Timing attack* Show firmware{{Tutorial boilerplate}}
<pre>#Imports See the following for IV Attackusing:from Crypto.Cipher import AES* ChipWhisperer-Lite Classic (XMEGA)* ChipWhisperer-Lite Capture + XMEGA Target on UFO Board (including NAE-SCAPACK-L1/L2 users)* ChipWhisperer-Pro + XMEGA Target on UFO Board