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:

4020461947
1760731338
8693234357
0410240370
1549632650
3394334938
0244262340
3670131670
7747646477
1558512655
5308443738
6234556564
9795077759
4510650166
1884118181
5334545596
4514642896
9385177344
1384561666
4345420419
5273399608
8234410121
5264749280
5564524492
3275385641
5578777575
5335355333
3764575757
8434228322
5206400403
8812610587
6904174969
0975719539
4028474067
5399072007
1515114517
3662822863
5569275026
7717919907
8881110989
2381142387
3853610487
3174913382
6963513367
9943854387
8596554984
5065710567
3103200312
7826664827
8833443488
0771179371
2019990012
3999434399
6444143176
7972797127
0700439119
3841938122
6605499077
5587439379
4704574026
9700804789
1330623061
3337733674
5383563255
9779778193
5403273691
1402460793
7735824279
5854203773
8465503789
1390435147
5314637722
0797839316
8350239322
1914298126
2632338326
7772294722
9139239122
9436139341
1007107717
9767777775
5346764436
7020101201
9668688666
4906333466
5306786504
4060195469
9600647088
9976153040
9060790181
0795355009
3313777313
0843748738
9096361006
2598399535
3598782845
9548760093
3318330410
2393368493
3590322107
5148334423
3309720129
8355755807
5818326986
5348963007
3818778818
5313953991
6144334861
8549888944
8755355578
6575586697
0308114808
6375735901
9275145161
9301129276
1278171183
0905101005
0309230039
6561766617
9575889595
6913262996
4937224599
1559556037
4514209688
4137547276
4950777715
4314224444
6157222721
8533538535
1513813353
4270086632
8260734668
6408732890
8990184881
1736630190
0990934890
1100630161
8690866208
3663646637
2278882972

The puzzle

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

7769974968
7878030887
6661686951
3999449379
2425595125
6524836878
5363934155
6959780361
6349449851
5010295174
8594404258
8195732665
0790553360
7516794358
5730588123
0136515005
8024444044
7799662797
5918789179
8550333558
8165847581
0003903499
8087040837
9989898991
7711777121
7373077139
3498157431
3500540929
3115890427
1300998199
7014610641
1266962126
9376878899
5976059475
4392595429
4076520364
9316507707
1262966832
4014994662
1346596532
2552025025
9411101545
5858133815
5526595620
3637117613
0617817615
8744061845
1073705620
2044225615
9694891643
7766476676
5016406011
0824948872
4807686840
6104511160
7804900980
7716467300
6016552560
4806921359
0819604144
9481944897
9281298122
2882222885
3122212235
1207110627
1249418297
2515047892
6998324625
1723412632
7437012832
1141749177
2248826582
5434553234
0999909987
0315331015
1452233072
4704602934
6593049914
9123831014
9700839974
4964094080
8277424877
0500556660
1265642165
6674719764
7599652664
8423794860
9631794890
5693924767
7075916767
4487410844
5555555571
2006665402
6988689926
3794793477
3789490441
3294113871
6589159541
7161168476
9171395476
1331819889
5222318494
1631172860
8431855082
8379320342
1922391329
7351251550
8473838883
5336836353
8239112293
5914232307
8834114519
7754160119
6628414189
3709410349
1101111109
4264610246
6676662657
1394934919
4888860388
5426445526
0263305237
2277729767
9933909593
1666176616
6138875226
2500929515
4278149213
3105976636
4966776566
2872871982
6686906998
3190229073
4545524540
9111159191
4220279970
9975679991
4443774181
3153729190
2468854932

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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