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Difference between revisions of "Glitch Explorer"

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(→‎Using the Glitch Explorer - The Basics)
 
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{{Warningbox|For the older V3.x tools, see [[V3:Glitch_Explorer]]}}
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The Glitch Explorer allows an automatic exploration of a range of one or more parameter values. It means that the user can test multiple glitch setups at the same time and see the result in a nice scatterplot, highlighting the successful attempts.
 
The Glitch Explorer allows an automatic exploration of a range of one or more parameter values. It means that the user can test multiple glitch setups at the same time and see the result in a nice scatterplot, highlighting the successful attempts.
  
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[[File:Screen Shot 2016-07-12 at 4.15.30 PM.png|1100px]]
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[[File:glitch_explorer_overview_v4.PNG|1100px]]
  
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== The Glitch Explorer Window ==
 
The main window of the glitch explorer looks like this:
 
The main window of the glitch explorer looks like this:
  
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[[File:Screen Shot 2016-07-15 at 10.24.13 AM.png|400px]]
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[[File:glitch_explorer_window_v4.png|400px]]
  
 
In top, the output of the system combined with the parameters of the glitch is displayed (the 'output window').
 
In top, the output of the system combined with the parameters of the glitch is displayed (the 'output window').
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In bottom, you can adjust general parameters of the glitching system, such as what counts as a successful glitch or not and how many parameters to fiddle with.
 
  
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To start using the Glitch Explorer, you should first switch to the "Target Settings" tab and set the "Output Format" to be $GLITCH$. This will mean data is no longer sent to the terminal emulator when using the capture 1 or capture M buttons, but instead, is logged in the glitch explorer window.
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In bottom, you can adjust general parameters of the glitching system, such as what counts as a successful glitch or not and the ability to load existing data into the glitch explorer table.
  
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Then, you should define what is a Normal and a Successful Response. This information is used to highlight the individual attacks. You should use Python expressions here, where 's' is a str-type variable which contains the response of the system (ex.: s.endswith("123456")).
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== Using the Glitch Explorer - The Basics ==
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Here are a few steps that should be done before using the glitch explorer (example uses the ChipWhisperer Lite):
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<ol>
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<li>
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Connect the ChipWhisperer Scope and Target (example: run the <code>connect_cwlite_simpleserial.py</code> script)
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[[File: run_connect_script.png|800px]]
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</li>
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<br>
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<li>
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Set up the parameters for glitching (example: run the <code>setup_cwlite_glitch.py</code> script)
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[[File: run_glitch_script.png|800px]]
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</li>
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<br>
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<li>
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Setup the automatic reset aux module (example: run the <code>aux_reset_cw1173.py</code> script)
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[[ File: run_reset_aux_script.png|800px]]
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<br>
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<b>Note: This file may have to be edited if you later have issues with trigger timeouts. The trigger timeouts can usually be fixed by switching the appropriate lines in a copy of the script</b>
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<syntaxhighlight lang=python>
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# Reset before arming - more stable
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aux_list.register(Resetter.resetThenDelay, "before_trace")
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# Reset after arming - scope can catch entire reset
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#aux_list.register(Resetter.delayThenReset, "after_arm")
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</syntaxhighlight>
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to
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<syntaxhighlight lang=python>
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# Reset before arming - more stable
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#aux_list.register(Resetter.resetThenDelay, "before_trace")
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# Reset after arming - scope can catch entire reset
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aux_list.register(Resetter.delayThenReset, "after_arm")
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</syntaxhighlight>
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<b> Another note: Remember to run this script and disable the other aux module inside the "Aux Settings" tab.</b>
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</li>
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<br>
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<li>
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Change the glitch trigger source from manual to external single. Run this command in the python console:
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<code>self.scope.glitch.trigger_src = "ext_single"</code>
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</li>
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<br>
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<li>
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Register the change_glitch_parameters function as the glitch explorer iterator (example: run the <code>ge_widthoffset_vary.py</code> script). Changes to the step size and range that the glitch explorer covers can be customized by changing variables within this script and running the changed script.
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[[File: register_ge_iterator.png | 800px]]
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</li>
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<br>
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<li>
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Set the normal and successful outputs (example: using the firmware in glitch-simple, after editing the c to use the glitch1() function rather than the glitch_infinite() function)
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[[File: set_responses.png | 400px]]
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</li>
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<br>
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<li>
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Open the glitch explorer graph widget by pressing the <b>Plot Widget</b> button inside the Glitch Explorer Window.
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</li>
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</ol>
  
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The next step is to set the number of tuning parameters. You may want to start with 1 (0 is used to just record manual exploration attempts in the table) and then increment it to 2 or more later. This will generate another group in the list where you can tune the settings for each parameter:
 
  
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[[File:Screen Shot 2016-07-15 at 10.30.53 AM.png|400px]]
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Now you are ready to click the "Capture M" to start the exploration. </b>If you run into forced trigger issues go back to the previous steps where it was mentioned how to fix the issue.</b>
  
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Name - is just a reminder of what we are tunning.
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== Using the Glitch Explorer - Advanced ==
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Script Command - defines what will be modified. This string can simply be copied from the Script Commands tab of the main window.
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To get more detailed information of how to use the Glitch Explorer, follow the [[Tutorial A2 Introduction to Glitch Attacks (including Glitch Explorer)|A2]] and [[Tutorial A3 VCC Glitch Attacks|A3]] tutorials.  
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Data Format - defines what type of data will be inserted into the parameter.
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Range - defines the range from the minimum to maximum that will be swept for the parameter.
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Value - defines the current/start value of the sweep. This is NOT automatically set to the minimum value of your sweep since you may want to stop and continue later or attack a smaller number of traces. If you want to perform the full sweep, you must manually set this to the minimum of the range or click reset.
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Step - defines the incremented on each glitch attempt. When the value reaches the maximum defined by the range, it will loop around to the minimum and continue incrementing.
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Repeat - defines how many times to perform the same value. This can be used to determine the reliability of each glitch value.
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The last step is to set the "Generic Settings"->"Acquisition Settings"->"Number of Traces" to a value high enough to loop trough all the values combination set in the Glitch Explorer. It can be performed automatically clicking in the "Glitch Explorer"->"Traces Required"->"Use this value" button.
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If you want to create a script to fully automate this attack, check out the example in <code> chipwhisperer/software/scripting-examples/glitch_explorer_simple.py </code>.
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Now you can use the "Capture M" to start the exploration.
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Latest revision as of 04:59, 6 September 2018

For the older V3.x tools, see V3:Glitch_Explorer

The Glitch Explorer allows an automatic exploration of a range of one or more parameter values. It means that the user can test multiple glitch setups at the same time and see the result in a nice scatterplot, highlighting the successful attempts.

Glitch explorer overview v4.PNG

The Glitch Explorer Window

The main window of the glitch explorer looks like this:

Glitch explorer window v4.png

In top, the output of the system combined with the parameters of the glitch is displayed (the 'output window').

In bottom, you can adjust general parameters of the glitching system, such as what counts as a successful glitch or not and the ability to load existing data into the glitch explorer table.

Using the Glitch Explorer - The Basics

Here are a few steps that should be done before using the glitch explorer (example uses the ChipWhisperer Lite):

  1. Connect the ChipWhisperer Scope and Target (example: run the connect_cwlite_simpleserial.py script) Run connect script.png


  2. Set up the parameters for glitching (example: run the setup_cwlite_glitch.py script) Run glitch script.png


  3. Setup the automatic reset aux module (example: run the aux_reset_cw1173.py script) Run reset aux script.png
    Note: This file may have to be edited if you later have issues with trigger timeouts. The trigger timeouts can usually be fixed by switching the appropriate lines in a copy of the script 
    # Reset before arming - more stable
aux_list.register(Resetter.resetThenDelay, "before_trace")
# Reset after arming - scope can catch entire reset
#aux_list.register(Resetter.delayThenReset, "after_arm")

    to 

    # Reset before arming - more stable
#aux_list.register(Resetter.resetThenDelay, "before_trace")
# Reset after arming - scope can catch entire reset
aux_list.register(Resetter.delayThenReset, "after_arm")

    Another note: Remember to run this script and disable the other aux module inside the "Aux Settings" tab.


  4. Change the glitch trigger source from manual to external single. Run this command in the python console: self.scope.glitch.trigger_src = "ext_single"


  5. Register the change_glitch_parameters function as the glitch explorer iterator (example: run the ge_widthoffset_vary.py script). Changes to the step size and range that the glitch explorer covers can be customized by changing variables within this script and running the changed script. Register ge iterator.png


  6. Set the normal and successful outputs (example: using the firmware in glitch-simple, after editing the c to use the glitch1() function rather than the glitch_infinite() function) Set responses.png


  7. Open the glitch explorer graph widget by pressing the Plot Widget button inside the Glitch Explorer Window.


Now you are ready to click the "Capture M" to start the exploration. </b>If you run into forced trigger issues go back to the previous steps where it was mentioned how to fix the issue.</b>

Using the Glitch Explorer - Advanced

To get more detailed information of how to use the Glitch Explorer, follow the A2 and A3 tutorials.

If you want to create a script to fully automate this attack, check out the example in chipwhisperer/software/scripting-examples/glitch_explorer_simple.py .

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