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Tutorial A5-Bonus Breaking AES-256 Bootloader

3,769 bytes removed, 13:36, 29 July 2019
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{{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}}
* Jupyter file: '''PA_Multi_1-Breaking_AES-256_Bootloader.ipynb'''
= Attacking the IV =
Steps:
* Investigation
** Look at bootloader code
** Move trigger
** Record 1
** Show different instructions in trace
* Making the attack feasible
** Capture a bunch (500?)
** Apply decryption
** Look at one bit
** Find means + plot
** Find differences + plot
* Automating the attack
** Finding the attack points
** Getting a single bit
** Building the IV bytes
* Full script in appendix
Example:== XMEGA Target ==
<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
def initPreprocessing(self)https: self//chipwhisperer.preProcessingResyncSAD0 = preprocessingreadthedocs.ResyncSADio/en/latest/tutorials/pa_multi_1-openadc-cwlitexmega.ResyncSAD(self.parent) self.preProcessingResyncSAD0.setEnabled(True) self.preProcessingResyncSAD0.setReference(rtraceno=0, refpoints=(6300,6800), inputwindow=(6000,7200)) self.preProcessingResyncSAD1 = preprocessing.ResyncSAD.ResyncSAD(self.parent) self.preProcessingResyncSAD1.setEnabled(True) self.preProcessingResyncSAD1.setReference(rtraceno=0, refpoints=(4800,5100), inputwindow=(4700,5200)) self.preProcessingList = [self.preProcessingResyncSAD0,self.preProcessingResyncSAD1,] return self.preProcessingListhtml#tutorial-pa-multi-1-openadc-cwlitexmega
class AESIVAttack(object): numSubKeys = 16= ChipWhisperer-Lite ARM / STM32F3 Target ==
@staticmethodSee the following for using: def leakage* ChipWhisperer-Lite 32-bit (textin, textout, guess, bnum, setting, stateSTM32F3 Target): knownkey = [0x94, 0x28, 0x5D, 0x4D, 0x6D, 0xCF, 0xEC, 0x08, 0xD8, 0xAC, 0xDD, 0xF6, 0xBE, 0x25, 0xA4, 0x99, 0xC4, 0xD9, 0xD0, 0x1E, 0xC3, 0x40, 0x7E, 0xD7, 0xD5, 0x28, 0xD4, 0x09, 0xE9, 0xF0, 0x88, 0xA1] knownkey = str* ChipWhisperer-Lite Capture + STM32F3 Target on UFO Board (bytearray(knownkey)including NAE-SCAPACK-L1/L2 users) ct = str(bytearray(textin))* ChipWhisperer-Pro + STM32F3 Target on UFO Board
aes = AEShttps://chipwhisperer.new(knownkey, AESreadthedocs.MODE_ECB) pt = aes.decrypt(ct) return getHW(bytearray(pt)[bnum] ^ guess)<io/pre>en/latest/tutorials/pa_multi_1-openadc-cwlitearm.html#tutorial-pa-multi-1-openadc-cwlitearm
= Appendix D AES-256 IV Attack Script = ChipWhisperer Nano Target ==
'''NB: This script works tutorial is not available for 0the ChipWhisperer Nano.10 release or later, see local copy in doc/html directory of chipwhisperer release if you need earlier versions''' Full attack script, copy/paste into a file then add as active attack script: <pre>#IV Attack Scriptfrom chipwhisperer.common.autoscript import AutoScriptBase#Imports from Preprocessingimport chipwhisperer.analyzer.preprocessing as preprocessing#Imports from Capturefrom chipwhisperer.analyzer.attacks.CPA import CPAfrom chipwhisperer.analyzer.attacks.CPAProgressive import CPAProgressiveimport chipwhisperer.analyzer.attacks.models.AES128_8bit# Imports from utilList # Imports for AES256 Attackfrom chipwhisperer.analyzer.attacks.models.AES128_8bit import getHW #Imports for IV Attackfrom Crypto.Cipher import AES class AESIVAttack(object): numSubKeys = 16  @staticmethod def leakage(textin, textout, guess, bnum, setting, state): knownkey = [0x94, 0x28, 0x5D, 0x4D, 0x6D, 0xCF, 0xEC, 0x08, 0xD8, 0xAC, 0xDD, 0xF6, 0xBE, 0x25, 0xA4, 0x99, 0xC4, 0xD9, 0xD0, 0x1E, 0xC3, 0x40, 0x7E, 0xD7, 0xD5, 0x28, 0xD4, 0x09, 0xE9, 0xF0, 0x88, 0xA1] knownkey = str(bytearray(knownkey)) ct = str(bytearray(textin))  aes = AES.new(knownkey, AES.MODE_ECB) pt = aes.decrypt(ct) return getHW(bytearray(pt)[bnum] ^ guess) class userScript(AutoScriptBase): preProcessingList = [] def initProject(self): pass  def initPreprocessing(self): self.preProcessingResyncSAD0 = preprocessing.ResyncSAD.ResyncSAD(self.parent) self.preProcessingResyncSAD0.setEnabled(True) self.preProcessingResyncSAD0.setReference(rtraceno=0, refpoints=(6300,6800), inputwindow=(6000,7200)) self.preProcessingResyncSAD1 = preprocessing.ResyncSAD.ResyncSAD(self.parent) self.preProcessingResyncSAD1.setEnabled(True) self.preProcessingResyncSAD1.setReference(rtraceno=0, refpoints=(4800,5100), inputwindow=(4700,5200)) self.preProcessingList = [self.preProcessingResyncSAD0,self.preProcessingResyncSAD1,] return self.preProcessingList  def initAnalysis(self): self.attack = CPA(self.parent, console=self.console, showScriptParameter=self.showScriptParameter) self.attack.setAnalysisAlgorithm(CPAProgressive, AESIVAttack, None) self.attack.setTraceStart(0) self.attack.setTracesPerAttack(100) self.attack.setIterations(1) self.attack.setReportingInterval(25) self.attack.setTargetBytes([0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15]) self.attack.setTraceManager(self.traceManager()) self.attack.setProject(self.project()) self.attack.setPointRange((4800,6500)) return self.attack  def initReporting(self, results): results.setAttack(self.attack) results.setTraceManager(self.traceManager()) self.results = results  def doAnalysis(self): self.attack.doAttack()</pre> = Attacking the Signature =
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