An OPC Giveaway Scavenger Hunt

Today's post isn't about magic, it's about my experience with the recent scavenger hunt put on by Organic Playing Cards that gave the community a chance to win a lot of decks of playing cards. If you've never participated in a scavenger hunt, or "capture the flag", style event before, try to keep an eye out in the different communities because they're really fun. Basically, you solve different puzzles to win prizes.

Anyways, here's how my weekend went!


It was Saturday afternoon, I had just finished lunch and a message popped up on my phone. It was an @everyone mention from the Organic Playing Cards (OPC) Discord server announcing a scavenger hunt. I just had to see this!

Starting off the announcement with the good bits, the prizes for the top 3 winners of this hunt were very tempting:

  • 1st Place: 6 decks of OPC Sweet Peas, 1 Exotic V1, 1 Exotic V2, and 6 decks of the next deck to be released!
  • 2nd Place: 6 decks of OPC Sweet Peas and 6 decks of the next deck!
  • 3rd Place: 3 decks of OPC Sweet Peas and 3 of the next!

Holy smokes, that's a fantastic set of prizes! The premise itself was straightforward. We would be given a puzzle and the solution to the puzzle was the key to open the next puzzle. 12 puzzles in total and the winners were the folks who finished first.

Each puzzle was different from the others, more or less, and in general they didn't require tools -- but knowing how to program would've definitely made some of them easier. Also, one of the puzzles (number 9 -- which was actually the 10th puzzle), kind of required using a desktop and not a mobile phone. The solution for it was in the Discord server's icon which, on mobile, isn't really visible.

While I did get stuck on one or two of the puzzles -- ironically, the one I was stuck on the longest turned out to be the easiest of all of the puzzles -- I breezed through the entire thing. When I got up towards the end, I had to pause to go to the airport. I had a trip to Nashville (which you'll hear about in my next post) and the scavenger hunt had to wait. This shouldn't have been a huge issue though since I was 2 or 3 puzzles ahead of everyone else.

When I got to the airport, after getting food, I hopped onto my phone and started taking a look at the puzzles. Unfortunately for me, I was on puzzle number 9 ... which required a computer. At least, a computer would have made it a lot easier. However, I solved it nonetheless and moved on to number 10 (the "11th" puzzle).

Number 10 was an interesting puzzle, very different from all of the others. It wasn't a simple "convert this number into a letter" or "figure out the riddle" kind of puzzle, it was 10 different chunks of assembly instructions. It helps that I work with assembly routinely, so I just read through it and had answers quite quickly. There was an error on the 10th chunk though, but when I asked about it it was cleared up and I was able to move on. Coincidentally, I got rate-limited by Discord at this time and had to use multiple devices to open the number 11 puzzle.

The number 11 puzzle, or the "final" 12th puzzle, through me for a loop. The Discord channel name was AES, and another channel had a complete sBox. There was also a phrase -- finalstage -- in italics in the main channel, which I assumed would be the key. And then, my plane started boarding. Luckily I was in a later zone so I quickly slapped together a general AES decrypt method using the key -- since the sBox was the default AES sBox -- and... it didn't decrypt. What?!

I wasn't too worried. Nobody else was even close to my progress and the number 10 puzzle (the assembly) should have slowed folks down a bit. Unless there's a tool out there that solves that one for you, I felt like I had the upper-hand advantage due to my day job =P

After arriving in Nashville and meeting up with my friends, we ended up doing a really late night and getting in closer to 5am. I was in no shape to do any type of scavenger hunt, I was exhausted. I did take a look at the current stats and only one other person made it to number 10, so I was thinking I'd just wake up and knock out 11. And then, I woke up around 10am. Someone -- no the other person who made it to number 10 originally -- but someone else already finished 11! Well shucks.

There was also a hint released for the puzzle so I took a look at it and based on the single picture, I knew that it wasn't the full AES algorithm, it was only a single round of it. This would require a custom solution to be written, something I couldn't do on my phone. I went out to grab a coffee and while I was out, the other guy finished 11 too! Only one spot left, yikes!

Back in my hotel, I wrote a quick script to solve the puzzle and bam -- it didn't work. It should have worked. At least, I wanted it to work. My head was killing me. The coffee wasn't helping. My friends were all waking up and ready to go out for breakfast. Why didn't it work? Ugh. "I'll get back to this after breakfast," I said.

I didn't get back to the apartment until 3am. Yay! 3rd place was grabbed, but not by me.

Why didn't my solution work? Because of a single-character typo. Man I love programming =P

One of my friends that was with me said, when we were at breakfast, that he knew once I didn't get first place that I stopped caring. Which, honestly, was partially true. I've always been a fan of "capture the flag" events and competitions, especially when coding and / or encryption are involved. You're number 1, or you're not. However, the prizes for 2nd and 3rd place were pretty great so I really did aim to finish it.

Sunday afternoon, when I was finally able to turn on my laptop again, I immediately spotted the type (it was an `&` character instead of a `^`), I changed it, ran the code, and had the correct answer. In hindsight, I could've solved it on the plane ride to Nashville. But, I didn't.

The moral of all of this isn't about my experience, it's actually for everyone else. Even if you see someone ahead of you, even if someone's at the very end and you're still far behind, you still have a chance to win. Don't give up because you never know until you know (^_^)

I really want to send a big shout-out to Luis from OPC for putting on the scavenger hunt. Not only was it a lot of fun -- and the potential prizes were amazing looking -- but several of these puzzles required a heck of a lot of work. Awesome event y'all!

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