AND!XOR DC29 Badge

IC shortage got you down? Shift our DC badge plans to something a little more discrete.

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You got a badge? RTF Logs on how to get started!

One part SMD challenge, one part reverse engineering, two parts cryptography, one part Matt Damon, zero parts Integrated Circuits -> Shaken, not stirred.


DEF CON was finally canceled last year due to a pandemic... and now we have it coming back in hybrid form. Unfortunately, the aftermath has still affected our electronics supply chain of integrated circuits which we needed for our original DC29 project. To overcome this, we designed a new badge...with no IC's. This years badge is a pure hardware challenge and analog, completely made of passives. We hope you enjoy the puzzles, we enjoyed designing them. Project will be open sourced sometime in September.

This wouldn't have been possible without our Philanthropist Backers and Generous Sponsors. Show them some love because without them, you hackers wouldn't be getting badges and instead would have to resort to the pool party on the roof. w00w00!!!


  • DEFCON 29: Paris / Bally's , Las Vegas NV
  • Some proxy drops may be going out...


  • Aug 4th - Aug 8th, 2021


Yes, this is a soldering kit. But not your normal kind. Is there a schematic and BOM included? NOEP!!! Its part of the challenge :) Which is why we used that sexy Osh Park After Dark... You will need to identify the components included, reverse engineer the board to see how the traces connect, crack the cipher that identifies which components go where, flux & solder, then celebrate. Some folks may not have all the tools of the trade, so here is a list of things we think you may need to be 1337. 


Public Slack Workspace:

We highly recommend collaborating together in our Slack for completing the challenges.

  • 1 × Main PCB Link to OSH Park for making your own boards available after the CON
  • 1 × REDACTED PARTS LIST - Crack the Cipher

  • The Cipher

    Hyr0n07/25/2021 at 04:57 0 comments

    So... no schematic, no BOM, and the markings on the PCB have little pictures. LOLZ! Don't fret, this is where the fun comes in. It was mentioned in the earlier log, but essentially you need to crack a cipher. This can be done quantitatively (i.e. using frequency analysis) or qualitatively (i.e. seeing how the images relate to one another, putting them in the right order, and understanding how they map to the alphabet). To do this, you need SAMPLES and a good shot of the badge. See below and get crackin! We highly recommend you collaborate with others on site at the CPV or online in our Slack (OR BOTH!) 

    The Key

    Sample 0

    Sample 1

    Sample 2

    Sample 3

    Sample 4


    These may also lead you to understand how the front face castellated PCB's get properly soldered on...

  • The Challenge

    Hyr0n07/12/2021 at 06:05 0 comments

    The badge challenge can be broken down in to different levels of difficulty. While we highly encourage you attempt to 100% this, at the very least there can be different levels of satisfaction in whatever floats your boat. If completed, the badge does serve a functional purpose and could be integrated for use in to other hardware hacking projects.

    The Facts

    • There is no schematic and competent identifiers are encoded with a cipher
    • The core badge PCB serves as a backplane
    • The artwork on the front PCBs are castellated and include circuit traces
    • The passive components must be soldered in addition to the front PCBs
    • The component identifiers are printed with a about them apples?

    Level 0 - Wear It

    You may just be happy earning a badge and want to rock it as is. This challenge involves figuring out how to obtain a badge (via DEF CON hacker shenanigans or Philanthropy), then attaching the lanyard, and wearing it.

    Level 1 - Decorative Soldering

    Simple soldering. You don't know the correct order of the front face castellated PCBs, but like them placed in a way which artistically makes you happy. Flux and solder them down to the front, forever hiding Buffalo Rick. If you plan on trying to complete the challenge, we DO NOT recommend you do this! 

    Level 2 - Identification

    You have to know the parts, before you figure out where they go. Using a multimeter and/or magnifying glass you correctly identify the kit components and generate your own BOM. Additionally we recommend using the continuity test function and  trace out the connections; start drawing a schematic and leave blanks for the unknown components, eventually you will reverse engineer the potential path of electrons.

    Helpful Link: SMD Resistor Code Calculator

    Level 3 - Crack The Cipher

    So normally a soldering kit would give you reference markers for all of the components. What the hell fun is that? This is encoding, not encryption, it is a cipher we have created and you must crack it. This is a great opportunity to learn some new skillsets from our friends at the Crypto & Privacy Village (CPV) if cipher's aren't your thing (or try making friends in our Slack Channel). We have had the cipher tested by some of our CTF Hacker Fam and can confirm it is both solve-able qualitatively or quantitatively. That being said, it doesn't matter if you a left vs right brained kind of person, both paths can lead to success. Just so there is a common frame of reference, here are the cipher symbols in alphabetical order (note that this order is NOT a hint to solving it or indicative of the actual order of the cipher, I just need a way to list it out in the log and do not want to send you down the rabbit hole):

    • Apple
    • Baseball
    • Car
    • COVID
    • DOGE
    • Hammer
    • Horseshoe
    • New Jersey
    • Penguin
    • Pizza
    • Poker Chip
    • Rain Drop
    • Rocket Ship
    • Tree
    • Waves
    • Weed

    Now it is VERY difficult to solve a cipher without some samples to go off of. You have them silk screened on the badge, but there will be additional logs posted with further hints necessary to crack the cipher (we don't want to mix hints with the general challenge description). Eventually once cracking the cipher go back to the draft schematic you reverse engineered and start translating and populating the unknown components. Note that the hints on the cipher page also will let you know the correct order of the face plates, if permutation trial and error isn't your thing...

    Level 4 - Functional Soldering

    In an effort to stir debate you may ask why we recommended 63/37 solder? Because other alloy ratios have a range of melting point, but the 63/37 alloy ratio perfectly melts at 183 degrees Celsius (361.4 Degrees Fahrenheit). Can you use any other solder? Of course, we're not the boss of you.

    So, at this level you know what you have and where it goes. Time to flux up those pads, tin those tips, and get to soldering! This is where the final steps post component soldering get interesting. You can determine the correct...

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Enjoy this project?



Mike Szczys wrote 07/16/2021 at 18:35 point

Look AND!XOR, you can keep asking, but I'm never gonna give you up.

  Are you sure? yes | no

Hyr0n wrote 07/25/2021 at 05:45 point

But would ever let us down?

  Are you sure? yes | no

Mike Szczys wrote 07/26/2021 at 16:14 point

Well I'll certainly never run around and hurt you.

  Are you sure? yes | no

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