The Near Future...

[M's]

All this smarty talk makes me feel like Homer J Simpson, so I'll just be over here in the corner with my comic book.

[Boss Llama]

Okay, fine, I lied, Alizee.

"This message contains the fifth of six clues for the final puzzle. It is an exciting time to be a gamer here at The Ville. Updates and patches are being released in TF Minecraft SMNC and others. Sometimes it is hard to decide which game to even play. It makes me wish I could play them all at once. With the Steam Summer Sale now going on it will be even harder to decide what games to play and how much time to dedicate to each one. There have been some pretty good deals already and more deals are no doubt coming up in the near future as other games are marked down for purchase. Just because there are a lot of new fun games does not mean we should neglect the classic old ones though. More games to play just means more games to love. The near future holds more than game sales too. One more cipher clue after this and then the final puzzle will spill its secrets. ALABAMA SIX FIVE XAVIER SEVEN JUILLIARD."

So, it was a straddling checkerboard with the following key:

Code: Select all

  8 2 1 0 3 4 5 9 6 7
  A T   O N E   S I R
1 B C D F G H J K L M
5 P Q U V W X Y Z . _

I can explain how I figured it out in a later post, but I only realized Alizee's checkerboard image was a hint after I had figured out what kind of cipher it was.

Nicely done, sir

Just a quick explanation of how a Straddling Checkboard works:

-A ten letter keyword or phrase is selected, and written above a 10x3 grid. Each letters is assigned the number that matches its alphabetical order in the keyword. That's the row of numbers across the top (I won't mention what my keyword was - I'll leave that to Coyote to describe when he has the time).

-A phrase with 8 (different) letters and 2 spaces is chosen, and placed in the first row below that. The two numbers that match the spaces in the 8 letter phrase are written on the bottow two rows. "At One Sir" is a good phrase here, as it uses 8 of the 9 most common letters in English - this exact phrase and layout was used by at least some Soviet spies during the Cold War (though they did some more stuff to it afterwards). Because the spaces line up with 1 and 5 on top, those are the two numbers that go on the left.

-The rest of the alphabet is filled in, in order, in the remaining spots. A period and a space go on the end.

-Each letter in the message gets the number made by reading the left number first, then the top number, for its row and column. The letters in your 8 letter phrase use just a single number (which is why it's good that they're the most common ones), while the rest will have a two digit number.

Done!

-To read the encryption, look at the first number. If it's anything other than a 1 or a 5 (in this case), it's a single digit number, because all two digit numbers start with one of those two. Transcribe the text, and move on to the next digit. Repeat. If the number is a 1 or a 5, it's a two digit number, because no single digit value is attached to those two. Add the next digit to it, and transcribe the text. Move to the next unused digit, and continue. Repeat until done with text.

It's a nifty code, because it's really a single substitution cipher (every plaintext letter only is replaced by one thing), but because some use a single digit, and some use multiple digits, normal frequency analysis won't crack it straight away. If you suspect you're dealing with a checkerboard though, you can still use it to start unravelling things, which I'm guessing is what Coyote did. Like many ciphers, it looks much harder than it actually is!

[CoyoteCreed]

Two quick things. One, the clue

"Also, our URL may soon avail you."

in cipher 4 of 6 was used in this puzzle. The keyword Alizee used to set the column numbers for the straddling checkerboard was our URL, as you can see:

Code: Select all

  E H I L L N S T U V   <--alphabetical order
  1 2 3 4 5 6 7 8 9 0

  T H E V I L L U N S   <--keyword order
  8 2 1 0 3 4 5 9 6 7

  8 2 1 0 3 4 5 9 6 7
  A T   O N E   S I R
1 B C D F G H J K L M
5 P Q U V W X Y Z . _

Who knows why he used 0 for the last digit instead of the first, but whatever. I didn't actually try to figure out what the keyword was until he generously decided to "let me explain it." Two, here is the running hint list:

Part 1: EAGLES UMBER'D QUAKE NORWAY O ZEAL
Part 2: GEM FOUR PESTILENCE ZERO DOMAIN BAKERS
Part 3: MIKE YANKEE CHARLIE EIGHT THREE LIMA
Part 4: RUNWAY KICKOFF WALLABY VASSALS IGUANA FARMING
Part 5: ALABAMA SIX FIVE XAVIER SEVEN JUILLIARD

Allow me to rearrange the hints so far, inserting some illuminating gaps:

Code: Select all

ALABAMA
BAKERS
CHARLIE
DOMAIN
EAGLES
FARMING
GEM
---
IGUANA
JUILLIARD
KICKOFF
LIMA
MIKE
NORWAY
O
PESTILENCE
QUAKE
RUNWAY
---
---
UMBER'D
VASSALS
WALLABY
XAVIER
YANKEE
ZEAL

ZERO
---
---
THREE
FOUR
FIVE
SIX
SEVEN
EIGHT
---

I'll go way out on a limb and guess the final hint words are ONE, TWO, NINE, and words beginning with H, S, and T.

[Boss Llama]

Who knows why he used 0 for the last digit instead of the first, but whatever.

I'm a pen and paper gamer, and on a D10 (10 sided die), 0 = 10

[CoyoteCreed]

So, the first step in solving this cipher was:

I'll point out one thing, the number of number characters in the coded message is 1367, a prime.

In other words, we can't divide the number of digits evenly into groups larger than one. Thus, we were looking for a type of cipher that yields either

1) a sequence of single digits or
2) digits in groups of different sizes

There aren't a lot of common ciphers like this. Looking through Wikipedia's classical ciphers and this ACA list, I came up with a few initial candidates:

VIEW CONTENT:

More:

Code: Select all

11 : 34
22 : 2
33 : 1
44 : 18
55 : 15
66 : 1
77 : 1
88 : 2
99 : 2
00 : 4

555 : 6
All other triples: 0

Too tired for explanation right now, but the ciphers I'm looking at are Monome-Dinome, Morbit, and Pollux. I'm hoping it's not a Tridigital.

I don't think its a Tridigital since by your chart, there's an occurrence of every double digit, which, unless my understanding is wrong, wouldn't happen with Tridigital since one number would only be used for word breaks.

Vulcan's right; it couldn't be Tridigital. Morbit was also out, because it uses only 9 digits and 0-9 are all present in the ciphertext. I tried cracking it by hand as a Pollux cipher based on how the previous ciphers in this series had begun, but couldn't even find a possible decryption that was internally consistent. I decided to give monome-dinome a shot.

I soon realized monome-dinome couldn't be a solution. In monome-dinome ciphertext, there will be two digits that will never appear twice in a row; in Alizee's cipher, all ten digits appear twice in a row at least once. However, at this point, I stumbled upon a possibility I had initially missed: the straddling checkerboard, closely related to the monome-dinome.

I had no idea how to start cracking a straddling checkerboard. I found this site, part of some instructions on how to write a monome-dinome/straddling checkerboard-cracking computer program. Now, to fully define a straddling checkerboard key, such as the ultimate answer to Alizee's cipher:

Code: Select all

  8 2 1 0 3 4 5 9 6 7
  A T   O N E   S I R
1 B C D F G H J K L M
5 P Q U V W X Y Z . _

we need to fill the grid with the correct characters, find the order of the column digits, and find the correct two row digits. As it turns out, essentially the only important step in cracking a straddling checkerboard is choosing the row digits properly. I quote from aforementioned site:

If we know the row digits of the key, we still do not know the order of the column digits, or the ordering of the letters within the grid. We cannot decipher the text, knowing only the row digits. But happens when we try to decrypt a text using a key that is correct only in having the right row digits? We'll have the wrong values for every output - but, we'll have combined the right digits together....

The result of decrypting with a key that is incorrect in all respects save that it has the correct row digits is a simple substitution cipher of the plaintext. We don't, of course, know the key to this substitution, but simple substitution ciphers we know how to break.

We have, by identifying the row digits, converted a complex cipher into a simple one that can be broken without trouble.

So, how to pick the row digits? They're used to encrypt any characters in the bottom two rows, so they're likely to be the two most frequent digits. We'd already done the frequency analysis:

Code: Select all

5 : 264
1 : 252
7 : 244
4 : 151
6 : 92
8 : 86
2 : 84
0 : 71
3 : 68
9 : 55

57 => 175
71 => 69
45 => 62
14 => 47
74 => 40

The main row digit candidates, by far, are 5, 1, and 7. Now, the frequency analysis of two-digit combinations shows that 57 is over twice as common as any other. Probably, this means 57 is the encryption of something absurdly common (as it turns out, space), and probably that means the only way 1 is so frequent is that it's a row digit. But how to be sure, and how to break the remaining tie?

My answer: trial and error. It's a lot of busywork from here, so I used the online "straddling checkerboard solver" at this site. I put that in quotes because it only does some of the work. Using an arbitrary grid, I just used my row digit guesses to "decrypt" the text into what was hopefully a simple substitution cipher of the proper plaintext. As it turns out, I couldn't even quite do that with this tool, because it made no allowances for enciphered punctuation; it tried to make everything a letter. Regardless, I now had generated some (probable? possible?) substitution ciphers to work on.

At this point, I became even lazier. I went to the automatic patristocrat (i.e., a cryptogram with the spaces removed) solver here and dumped each of my results in. The "substitution cipher" resulting from guessing 1 and 5 as the row digits yielded:

t hips me p pages contain ps the s fifths of spixsclueps for s the s final suleys it sips ans excitings times to s bes as gamers here sat s the s villey...

and so forth. So, it wasn't perfect; clearly S is supposed to be space, P is supposed to be S, etc. But it was the sort of message I was expecting to find, and so it was obvious that 1 and 5 were the correct row digits. This was enough to begin constructing the key. I set up an empty grid:

Code: Select all

  0 1 2 3 4 5 6 7 8 9

1
5

The first sentence was mostly clear: "This message contains the fifth of six clues for the final..." Using this as a starting point, I solved the puzzle by hand, eventually filling the grid:

Code: Select all

  0 1 2 3 4 5 6 7 8 9
  O   T N E   I R A S
1 F D C G H J L M B K
5 V U   W X Y . _ P Z

and yielding the complete plaintext message I submitted in a previous post. Finally, I rearranged the columns so that the second and third rows were alphabetized (and filled in absent letter Q), yielding the proper key:

Code: Select all

  8 2 1 0 3 4 5 9 6 7
  A T   O N E   S I R
1 B C D F G H J K L M
5 P Q U V W X Y Z . _

As for the keyword "THEVILLUNS" dictating the column digit order, it was the first thing I tried when Alizee implied I should know what the keyword was. I'd been looking for a place to use the URL clue he gave.

And that's how you crack a straddling checkerboard when you don't know what the hell you're doing.

[Boss Llama]

Impressive, Coyote! I don't even know what else to say to that. I put a couple major clues out, but you solved it without using either of them. I'll get the next installment up shortly, which is the penultimate puzzle - the last of the "clues" before the final.

In the meantime, best wishes for success in your upcoming real world puzzle games!

[CoyoteCreed]

I just want to add something that speaks to one of MrBlah's earlier posts:

As much as I have read into ciphers and cryptography in the past couple weeks, I am still lost and am clearly missing some valuable tools to solving these.

I wrote a blow-by-blow account of how I cracked that last one to show that it's possible to attack these ciphers without a lot of actual knowledge. I love puzzles, but I don't know much about ciphers. Seriously, I've learned more about ciphers in the past weeks just participating in Alizee's contest than I'd ever known before. Every site I linked to I've only found recently due to desperate, stab-in-the-dark Googling. My only real tools are logic and resourcefulness.

Alizee's not inventing any new ciphers (yet). If you lack better ideas, do what I do:
1. Deduce what you can about the ciphertext. Use some frequency analysis, if it makes sense.
2. Look at lists of various cipher examples until you find a few that look like they could produce the ciphertext you see.
3. Study each of those few candidate ciphers, looking for specific, peculiar characteristics of their ciphertexts. Determine whether Alizee's ciphertext has these characteristics and narrow the list of possibilities even further.
4. For the remaining possible ciphers, research how each can be cracked. Google extensively. The information and, quite often, helpful tools, are out there.

[MrBlah]

Honestly, it's almost like I've been taking a third class this summer in cryptography. So, a lot of new information, and not having enough time to adequately practice or attempt them. I've since subscribed to /r/cryptography though and there's daily puzzles now, so I should learn a bunch of new info there.

[Boss Llama]

VIEW CONTENT:

133313212323212233131132313111231123222113
111121232321231332321332111333332322211122
122321311232313111323223312212113123331331
311211133122132121212212131323122131123132
131331213223232123333222212112332311211121
123313232132112133111312311133223211112133
331113313312323311111133232331212321333311
212121321212222111132111113213231133331311
113231211233332331123221113211321111221111
111121111222312313312332312232211323111111
231323231311213122131113233321113213133333
311211113133232112311123131233331231112213
223211311122211112323111221131133223313131
312231111221321233111331211311111321221331
123321233311113312121311321311112212232323
113123131133113122213133313133321113221221
122211121231231112121111231113313321322331
131112321113112313333211113311231122231111
332333223131322132132121223112211131322113
311311233312311231111311312133211133113133
213222212211213123211133212131333311113121
211311312113131112333112132312213322112311
212111122121233312213312313311111231133112
331133113331112111112122212133312321311331
111111132312312231323133221221123113331323
133132331232122112311111233213331131111211
211321113321113132131221311333212121221211
121121311111131333231312132111231113113333
312313313133112113221113231121113311131111
333313231123322321313331211113121133313122
111121222131131112121312313122213231113311
133121221332223133123221312311223111311213
133232322122311212333111111123311311232131
312131231313122231121213232233321113321111
111313112311211113222132222331233332221331
132122323111131112122321323222332113313233
312122313131113311131111123332121312111122
213332211211331321313223132311233232322123
112213332333133133111123112213213221123321
132111112121223213222131121212311111232132
232312113222132332131322312212212112133211
323111111213112113113123113332212222311112
331231121112312221311111231113231233113121
111313331323113131313212321231313313131312
212111111223311111221321212131232321111133
213232313131231321131121313311232111311333
113121331231112113111333331223122122313113
332111122111331211132131213111113211132233
112323113313233133333122311111231123233113
231312132232223112111111111333211332313223

[CoyoteCreed]

mLite, is there any more room in that corner?

[CoyoteCreed]

Nice try. Morse code down the columns, left to right. 1 is dot, 2 is dash, 3 is gap.

"SIXTH OF SIX PARTS. HERE IS THE LAST CLUE YOU GET FOR THE FINAL PUZZLE, WHICH SHALL FOLLOW CLOSE ON THE HEELS OF SOLVING THIS ONE. WHAT COULD THE UPCOMING EVENT BE, I WONDER? WHAT SORT OF CHALLENGE WILL FACE THE GOOD PEOPLE OF THE VILLE? ALL WILL BE REVEALED SOON, AND THEN THE FUN WILL BEGIN. IF YOUVE STUDIED THE PREVIOUS FIVE CLUES CAREFULLY, YOU SHOULD ALREADY KNOW WHAT THIS CLUE HOLDS. THE ONLY QUESTION IS WHAT ORDER IT IS IN. THE LETTERS ARE IN POSITIONS ONE, TWO, AND FIVE. THE NUMBERS ARE IN POSITIONS THREE, FOUR, AND SIX. THE EARLIEST, FOR BOTH LETTERS AND NUMBERS, IS LAST. THE LATEST IS IN THE MIDDLE. THE MIDDLE OF EACH IS FIRST."

Now deciphering the hint words: As stated earlier, H, S, T, ONE, TWO, and NINE are the only ones left. The clues at the end give the order:

S T TWO NINE H ONE

So, evidently, order matters. Interesting.

[Boss Llama]

*sputter* *choke* *spit*

Ok, I knew you'd be able to solve that one fairly easily. I didn't expect it to be that easy! Morse is just a simple substitution, but columnizing it makes it pretty wierd looking. I'm guessing the filler 3's away the layout? Here I thought it would be too mean to fractionate it - guess I was wrong! Good job, and nice quick work.

[M's]

mLite, is there any more room in that corner?

There is plenty of room in my corner, I'll even share my Archie comic with ya.

[Powdermilkman]

mlite ill join you...do you have any casper the friendly ghost comics by chance.....

PMM

[NerevarineKing]

Finally, a place where I can feel slightly less smart than everyone and not care! Pass me the Archie comics!