Friday, July 17, 2015

"Big Grid (Three-Plus) Point" Solution





Back in simpler times, in mid-October, the CM unleashed this beast on us. After the CM cleared up a "little i, capital I" issue, we were off to the races, but he did offer one hint:



So we did the totally logical thing, the opposite of what he said. Not a word search eh? We’ll see about that. We proceeded to circle all the three letter words we could find. We went so far as to even break out all the scrabble words, which courtesy of Grant, elite-Scrabble-mind, took us no time at all.

Then what? Then we were deep enough down a rabbit hole to realize we needed to get out. So after a long night of what we will call “the scrabble theory”, we set this point aside and started on what would forever become known as THE ANAGRAMS POINT. But hey, that’s a different story for a different time.

Now, please let the record reflect that this point was completely unsolvable at the outset. There is nothing about it that gives you any clue as to what realm of possibility the mechanics lie in. None.

Then we got this three days later, on Monday:



Yup, there’s a letter and a number there, but we thought maybe it was telling us how an alphabet was keyed, or something b = 1 is what we were thinking. Not a pair of keys (which is what it turns out to be).



Then the next day, in the points update we got this little beauty. Thank goodness we’ve come a long way in interpreting CM clues, because at this point we were way over analyzing this clue. Today = “2day”, but before we had “be” = b and “first” = 1st. We were confused. We didn’t understand why the single letter preceded the 1 in the first clue with two shortened words, and the second clue had just one shortened word.

Likely sensing that we had nothing, the CM came back the next day with:



Adding three things up is a clue, okay, something about mechanics, but the possibilities were still endless. I don’t think we did much with this clue. We were in wait and see mode.

A week later we were finally thrown another bone, and this is when we first noticed the timeline becoming longer:



I still believe we have no idea what this hint was for. At the time we didn’t understand how “something plus something plus something” which only contained 2-pluses would fit with “triple-plus”. It wasn’t helpful for us.



The next day he tells us there are four phrases. And someone on our team notes there are four Xs including a terminating X. He also notes that the keys are letter number pairs, but that doesn’t help us understand why we’re adding three things together, and there’s really no clear way to proceed.

After 2 weeks, we were really no closer to having solved this point. I don’t think there was much experimentation either to be honest. Rather than release more hints, there were more points promised. Back then, the promise and distraction of more points was always good to reset the mind back to sanity. Little did we know the anagrams were coming. There is nothing sane about anagrams.

Finally, we get the “giveaway clues” which is a separate message with the key pair 4A:



And then the revealing method for the hint:



Finally we were able to piece together the method, and boy was it tricky. Given a grid, and a starting number/letter pair, you had to apply a rather insane non-linear method. Here's an example from the "hint" grid:

-- (1) Find the first instance of the key letter (e.g. 4 A) in the grid. Our first "A" is at position 7.
-- (2) Sum the key number (4) and the position (7) to get a shifting value; 4 + 7 = 11.
-- (3) Starting from the first instance of the key letter (7), shift forward by the shifting value (11) to get the next letter; 7 + 11 = 18, which is H, so "H" is the first letter in the message.
-- (4) Locate the first instance of the "H" in the grid; our first "H" is at position 10.
-- (5) Sum the shifting value (11) and the position of the first "H" (10) to get a shifting value for this letter; 11 + 10 = 21.
-- (6) Shift forward from the "H" (at position 18) by the shifting value (21) to get to the next letter; 18 + 21 = 39, 39 = "I".
-- (7) Repeat steps 4-6, until you reach a terminating "X" value (see the last letter in our "hint" grid).


What a nasty, nasty method. From there we went back to the original message and started trying all the key pairs. I coded up a flexible Excel based algorithm that let me flip through the keys to see what I could see.

What happened is you would get partial pieces of text that were readable but would break down a little bit during the decryption mechanics. When that started to happen I advanced the key by 1 to see if I could get the other three phrases to all land on the Xs that were to act as termination characters.

The CM says there was something built into the clues that would have told us that (perhaps triple plus helpful, heck if I know). I just applied my knowledge from solving ciphers that sometimes keys go in and out of phase (purposefully or via encryption errors) to find the remaining pieces of the messages.

You end up with these four letter/number key pairs, and four corresponding phrases:

-- B1: "thepatternx"
-- W2: "answerfourx"
-- K3: "threeiskx"
-- A4: "whatisthreex"

I’m embarrassed to admit how many hours we sat on the actual solution because we didn’t know if we were only supposed to post #threeisK. It wasn’t very straightforward. Finally, we realized the solution was just as simple as it appeared, and submitted the answer:



- Jim
Posted by at

7 comments:

  1. GrantJuly 17, 2015 at 2:06 PM

    One comment that must be made.

    Jim drastically understates here how he overcame a massive "Gotcha!" in this point. On the right side of the 6th line of the grid, there is a string of 3 R's, "r r r". You actually had to remove one of those R's from the grid to allow the method to complete. As-is, you would spell partial-English, partial-gibberish, and your phrases would never terminate at the X's. The amazing part to me was how quickly he figured this out. He does mention above in the solution that he was familiar with encryption/decryption problems that involve phase shifting, and that led him to explore that option ... but once he coded up the Excel file, we were only stuck on the 'extra letter' issue for literally just a few minutes.

    ReplyDelete
  2. AdamJuly 17, 2015 at 2:26 PM

    I'll let Jason chime in if he wants to with any more details on this. I recall that we were completely lost on this one for pretty much the whole time. I think we may have started to get close with the last clue, but clearly not all the way there.

    ReplyDelete
  3. Flocculent AbeJuly 17, 2015 at 2:28 PM

    I'll admit I got a little cute on this one (specifically for W2), but it is all in the first tweet.

    B the 1st 2 Us (W) it 4 A point. That's why the required hashtag was 3.

    ReplyDelete
    Replies
    1. JasonJuly 21, 2015 at 8:05 PM

      Ha that's pretty good.. Completely missed that since it was such a common phrase.

      Delete
  4. Flocculent AbeJuly 17, 2015 at 3:06 PM

    Also, "no + points + today" was supposed to get you started and "triple-plus" was supposed to hint at the rest of the method. I clearly failed in this case.

    The first step, once you've identified the key pairs, is adding three values (key number + position of first appearance of key letter + current position (position of first appearance of key letter)). After that step, you're adding four values to get each letter: key number + position of first appearance of key letter + position of first appearance of current letter + current position.

    Yeah, this wasn't my most elegant moment.

    ReplyDelete
    Replies
    1. GrantJuly 20, 2015 at 2:12 PM

      CM, there is still some discussion on whether or not the "r r r" was intentional or accidental. I know you would be hesitant to admit if it were accidental. Is there any way you can 'officially' settle the score on that?

      Delete
  5. GrantJuly 17, 2015 at 7:53 PM

    CM, personally (in retrospect) the method used is perhaps my favorite of the contest. It's more the clues that caused a lot of confusion, which I think is what you meant. The nature of the method made it tough to convey, but it really opened my mind to explore nonlinear encryption techniques.

    ReplyDelete

Subscribe to: Post Comments (Atom)