In early January, a number of large QR code advertisements started popping up around MIT/Cambridge. So, of course, I did what any geek would do: pulled out my phone and tapped Google Goggles. The QR code linked to ohaipuzzle.com. Unable to ignore a good puzzle, I spent the afternoon working with several friends (Geoffry, Mike, and Nathan), scattered across the country, to solve the puzzle (we came in 3rd). Now that the puzzle has reached its EOL I’ve put together a little walk through. If you want to take a crack at it first, I’d stop reading about now.

Warning and General Info
This is a puzzle intended for people with a decent amount of computer science knowledge. You’ve been warned! Specifically, this is a recruiting puzzle by a cool company called ITA Software. You may have heard something about Google’s attempts to buy them (usually a pretty good indicator of awesome levels). Speaking of Google, they actually did something similar back in 2004.

Spoilers below!

Phase One

If you look through the source you’ll see there’s nothing abnormal. The only interesting bit is the Google Analytics code at the bottom, but it’s standard. To tackle this section you’ll need to inspect the HTTP response headers. If you’re using Chrome you can do this by opening up your Developer Tools.

Specifically, you’re going to want to look at the X-Encode value. Seems odd, doesn’t it? Well, ctrl v it into your favorite base64 decoder to reveal a link to phase two.

Example X-Encode: aHR0cDovL3d3dy5vaGFpcHV6emxlLmNvbS8/NjB lMTg3ODgtMjgwZC00NmM3LTliMjYtZmNhYTZkMjU0MjMz

Example X-Decode: http://www.ohaipuzzle.com/?60e18788-280d-46c7-9b26-fcaa6d254233

Phase Two

And now the hard part. Let’s tackle the letter block first. 26 by 11 letters. 26. Letters in the alphabet, alright. 11. Why 11? What else is 11? FIND THE WORD. Ahhhh, alright. Let’s take the Fth (6th) letter of the first row, the Ith letter of the second, etc. There’s a couple different ways you can solve this. You can either do it manually (just make sure your count is correct) or you can write a script to solve it if you really want.

In this particular case we get the following: ANCHORCHIPS. What you get will vary as the letter block is different per person.

So, now we have the WORD. Next up, the UUID. By now you may have noticed the formatting of the url, handily providing our UUID. Our’s is 60e18788-280d-46c7-9b26-fcaa6d254233.

822-6. Honestly this one took quite a while to figure out. The key is in realizing that the formatting suggests a section of some document. Specifically RFC822: Standard for ARPA Internet Text Messages. Section 6 just happens to be Address Specification (specifically: email addresses).

With this in hand we now know that we need to give OHaiPuzzle the WORD we solved for, the UUID from our url, and our email address. The key for doing that is in the last part of the clue. 2616-9.5. Running with the way we solved the last clue, we discover that 2616-9.5 is the section for POST.

All we need to do is fire off a POST request. Excellent.

curl -d "WORD=ANCHORCHIPS&UUID=60e18788-280d-46c7-9b26-fcaa6d254233&EMAIL=YOU@DOMAIN.COM" http://www.ohaipuzzle.com

If you formatted everything correctly then you should get a response back congratulating you on completing the puzzle, giving you your place, and then revealing that the puzzle was sponsored by ITA Software. Then, a couple weeks later, a package might appear at your doorstep.

There you go, everything you need to know about the O Hai Puzzle. Twas fun, wouldn’t you say?

Current Stats for Solving Team
30,000+ people tried to complete ohaipuzzle.
152 completed ohaipuzzle
We placed 3rd

Dropbox then ran a dropquest
140k people completed the dropquest
We placed in the top 100