2012-11-17: Puzzle - First to solve wins

Posted at 2012-11-17 02:35:21 by SHD

For years I've had an idea in my head about a way to hide some information in a bunch of numbers. I actually got around to coding an implementation and figured I'd run a competition. The first person who figures out what the famous landmark is described by the second set of numbers below and posts the correct answer in the comments wins $100.

The hint

Here's a hint. The following numbers are a reference to the Eiffel tower:

8134906481
2192089359
2994790660
6136221348
2117961175
8192312925
6187081078
2996026696
2814928949
6835252863
2769191324
7661139504
1866908459
5002358224
5761564565
2061333201
1669119961
7752572255
5716996257
1702511575
8611212212
1391911691
1128998981
6251021522
5643111635
6643123420
5111949843
1221166570
1351665862
5151264089
1653318638
1491869184
9740404347
2913705608
1339059348
9399393345
0100059108
9319519537
0846604684
3183565131
4085908008
7227676272
4912846149
3814931944
7993177997
4292986654
4993858461
3227694628
7826121257
4297183809
5887406003
1850402067
0999656303
7326666097
3490656379
5057552507
5005536509
3033306463
9555056097
3849994373
4156861542
4000631886
1520677881
0557671842
6709298843
1818991883
8334831380
8186168841
2977707592
7487872848
9801854088
0821582937
4073835883
0291914707
1053922410
9806777899
1751957151
0873555008
4021818250
7259875585
0060270302
3522513205
1111179191
5320032045
8111178471
5526413202
2393232075
0990772395
2244510272
2703922045
6860862835
1117807818
2899129381
7722626097
7411771924
7311676887
9902172858
5109362011
1289872017
4152469338
2423224432
8447497448
3900395308
5282683632
5585515848
0840095632
5801615338
8174125642
5823797848
1299326338
1518881313
0207220725
1111119271
9559959445
8811778918
4729259311
0496629328
5770270775
2470381473
8731451513
0080100188
9562565532
3513551311
5777577755
7837778003
0357077088
5047558703
3757877212
4510351532
7667468353
3528133132
4553949435
4852555425
1279827892
3213772833
1213787697
4213904396
4593933990
4853143024
4529865065

The puzzle

Given the above hint, what famous landmark do the numbers below refer to?

7811008871
5586446151
0290070092
3141664311
6992559246
1318458146
1872876311
0709930396
4068854041
6549009842
9405252493
6467566744
9733193779
8049888049
2497332234
2407549297
9403353186
2407356369
9765249346
6766853462
7378718773
9903028093
8518559812
2749772973
6533359631
1063812793
3792629073
0796299913
5949118033
4100759831
4507745970
4565787565
7552112140
2398717800
7504168366
4508114510
7960667694
7334734377
8392777829
2557677657
7080090807
6881881386
8048848189
4355554435
5280558502
7621491507
5989698506
6843058596
3228058506
3628358485
4774974477
1512111011
6037867766
3763333633
0631530013
1067980193
6731107112
3634824574
3733597470
3567608436
2665339881
6379030270
6261739502
3358330085
6105239886
7272339270
0808330808
3639039006
7555545375
5660656582
6404904646
9622662923
9302933092
5435535555
0773137077
9472900503
5304957363
0334917919
9625923569
9605802060
9995556929
2067606746
0288810082
8155815288
7751918579
1283255028
4820016789
4128410229
8134356749
3259910016
8020700974
4099358793
7128906737
6104016493
4173058475
1149910694
1085518105
5355656945
7771515777
1343808413
1295519555
4374334447
9915774597
1602666020
6687118618
1985103027
4907330300
6205111408
6902324703
1367130708
5755547155
4800005284
9247696274
2000700007
4466554634
4945850157
8427390637
4174605054
1800906274
8952408074
2730424394
1649519445
2363263222
0338680003
8424118842
2449568754
0339240300
0434460675
1634442170
2341269803
4601901729
3239641926
6203243985
1056157981
3124234706
0666333606
5955151986
9674404766
1747747721
0050027005

Post the answer as a comment below. The first person to answer correctly with an acceptable explanation to how the answer was reached (rather than just a guess) wins $100, so make sure to use your correct e-mail address so I can contact you.

Note #1: People have noted that the numbers change whenever the page is reloaded. That's as expected. This puzzle is not an encryption as much as it is an obfuscation. That the numbers change is not important, as only the pattern in them will lead to the answer, which is of course constant.

Note #2: There was a bug in my post for a short while, which made the hint and puzzle basically the resolve to the same answer. This is fixed now. If you saved a copy the numbers before, just grab a fresh set.

Solved!

The second landmark was discovered by Batuhan Bozkurt, congratulations! The challenge has not yet been met entirely, though so I've decided to set a new challenge with the same method. The same $100 prize applies.

Redditor Bearasaurus has solved the final challenge too! For hints, check the followup post.

Tags:

Comments

Big Ben

Posted at 2012-11-19 09:55:28 by Colin Edward

I'm afraid Big Ben is not it. But be sure to include some explanation as to how the answer was reached, so I know it isn't just a random guess.

Posted at 2012-11-19 13:48:31 by Steven Don

I "solved" your puzzle, but I assume not in the way you wanted.

After giving it quite some hours, I failed to find any specific pattern (with a reasonable kolmogorov complexity) that would lead me to an answer. But in Reddit, you mentioned that you would be interested in statistical approaches that would lead to an answer (which I assume you are interested for increasing the security of the obfuscation?) so I exploited the fact that your website gives fresh batch of numbers at each reload so I grabbed about 1000 sets (with intervals in between, hopefully not causing trouble to your website, it handled the requests like a champ) and got to cracking.

Now your HTML formatting implies 10x10 blocks of data for each set. So that was a starting point when I first began looking at the problem. The grid is 70 x 20 so that implies 14 secret codes, 7 for each row.

I looked for what was common for each 10x10 block in each of the samples I gathered from your site. I found out that for each 10x10 block some digits occasionally never appears; for example in block 0x 0y, not all digits have to appear but one always appears at least once.

Once I looked at the remaining digits (that are common in all blocks at a particular coordinate), for the "hint", I was faced by these digits:

0485130
0021739

These are the coordinates in the form of degrees-minutes-seconds (dddmmss as you gave away generously in Reddit) of Eiffel Tower.

Once I ran the same process for the puzzle, the result was:

0295845
0310804

Which is the coordinates for the Great Pyramid of Giza.

Maybe this is disappointing, I don't know. If the website hadn't provided fresh batch of numbers, this method would not work. I assume, to strengthen the obfuscation, you could make sure one digit always appears at least once; but as long as the distribution isn't random, I suppose the answer could be extracted.

I've tried many approaches before this; I'm pretty confident that the pattern is not based on neighborhood relationships (as the answer can appear on edges, though wrapping around could be employed but still with it I failed to detect any patterns). I think it doesn't have anything (or much) to do with arithmetic on the digits (like summing / subtracting them). I tried various row/column patterns and couldn't come up with anything.

I also analyzed the 10x10 blocks containing the answer digits only once (so if the answer is 0 for that block, 0 appears only once in that block). But saw no obvious pattern at all. So this beats me in that regard.

If I am eligible for the prize for my answer, I would kindly ask you to donate it to the Doctors Without Borders foundation. If you are uncomfortable about it for some reason, you can choose to donate it somewhere else you see fit.

Thanks for the challenge, and although my curiosity has been partly satisfied, I'm still waiting for the answer that will allow me to solve this using a pen and paper using a single set of numbers.

Posted at 2012-11-19 16:36:10 by Batuhan Bozkurt

Batuhan, the answer is indeed correct. The Great Pyramid of Giza is the one I was looking for. The method you used is indeed not the one I was hoping for, as you haven't actually figured out the way the coordinates are encoded into the sets of numbers.

Still, I'm not one to dictate how the problem should be solved. I will make a donation to Doctors Without Borders for $100 in your name and post proof that I have done so.

Since I would very much like for somebody to solve the method, I'm including this static problem for a second attempt, and another $100. Being in a comment, the following set obviously does not change and encodes a third landmark.

2626513077384364666346599932245309032974209496921885110948315551555613
6549028370497764766953274173448611231555969009312435020244378244262894
9308377132331493394457637801172312372974892873367485438142538547446457
5987478672136633636156339295109196283474021313920015080695500005010510
9318473400638833698356337893287640679475088481921818727043921551931599
5758758671181690400516397336912974972974211231362065019596695870416497
1701226107698865022553554534544375771374969996927993180831110067651597
3203310324331357320447629709425333533533932743923435767555759732852649
0008077080336367751344339394399228589625005440340517458583553308156594
7467243472134765226056779555595344734475199118911888022882025906466417
0332300493776667648725560571112261196221231229957486429403779342535143
1366338577707417047142278890548676887286598087756091175002210326130060
5863902088494574497542911473583959753975898054668946115111760583633056
3673921092972792959782223331128568968982838265801286279605628360969080
5301986352763553665223261861393193111359891776463941295493449120391390
0463999640662807648743557375531417213379281451584481179187119326988940
4352555243298062697573961379660934698929891289118894828988929160129317
1871110111741174649945428445570098658283038728302510575750510526949009
3326333663020967498782260828822839081251556075505536114445618120357157
5602990599311067698721073220721651596922796029092045295295550390501233

The challenge now is to find the answer and a step by step description of how to extract the correct digits from it.

Posted at 2012-11-19 17:10:02 by Steven Don

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