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Unanswered Questions

125 questions with no upvoted or accepted answers
45
votes
1answer
4k views

Unsolved Mysteries: D'Agapeyeff cipher

The D'Agapeyeff cipher is an as-yet unbroken cipher that appears in the first edition of "Codes and Ciphers", an elementary book on cryptography published by the cryptographer Alexander D'Agapeyeff in ...
28
votes
0answers
3k views

Binary cryptogram from a friend

My friend sent me a "puzzle" in binary, and said that there are multiple steps to solving the puzzle, all of them including decryption. I translated the binary into text and he said that was a good ...
23
votes
0answers
1k views

One 'double agent' two-step on a waltzing floor

I'm in a jam – cornered I am! – No clue 'bout where to go Here's what went down, a pretty gown Some wine, a French chateau She whispered underneath her breath "Come dance with me and ...
17
votes
0answers
894 views

BFTIODFTTWKBCSC

This is my first self-developed cryptographic puzzle. I hope it is neither too hard nor too easy for you to break, and that you enjoy it. Please do not only post the answer, but also your way towards ...
17
votes
0answers
6k views

The Beale Papers

The background to this one's given here: http://www.damninteresting.com/89-263-201-500-337-480/ NB: These may not be a genuine cryptograms (current thinking is that these are gibberish); but I though ...
15
votes
0answers
1k views

Deus Ex crypto puzzle

There is an encrypted email in the recent Deus Ex: Mankind Divided game: From the game files, this appears to be the string: ...
14
votes
0answers
1k views

Is there a more efficient way to rotate the centre pieces on the Octo-Star?

I'm looking for a more efficient algorithm to rotate the center column of the Octo-Star puzzle 45 degrees. The situation below occurs when four properly-oriented edges are next to each other, ...
13
votes
0answers
255 views

Logic puzzle: Driving around the United States

For Super Bowl Sunday, here's a super-sized logic puzzle! This was a practice puzzle for a hunt I participated in a few years ago. There are ten delivery drivers driving around the United States of ...
13
votes
0answers
530 views

Peaceful Encampments

This math puzzle is due to Donald Knuth (as far as I know; maybe he got it from someone else) circa 2014. Consider a plain represented by the unit square. On this plain we want to “peacefully ...
13
votes
1answer
679 views

Creepy video on Youtube, with secret cipher built in

This showed up in r/deepintoyoutube: https://www.youtube.com/watch?v=j1ExfbH4Jew I've posted it around, and no one has solved it. I believe it is a cipher for a couple of reasons, at the end 26 ...
11
votes
0answers
249 views

A Pirate's Life For Me!

A Quick Note If you've seen any of my recent Riley riddles, then you knew this was coming. I've been working on this one for a week, and it was honestly quite tough to figure out what I really wanted ...
11
votes
0answers
423 views

Alternate, complex potions puzzle from HP fanfic

A long narrow room. The entrance is blocked by purple flame, the path onward blocked by black flame. On a table, the only thing in the room, are two dozen potions in opaque bottles. Half green glass, ...
10
votes
0answers
904 views

Decrypting the Key

So I've been trying to solve this Riddle called "Phage is Spreading.." ...
9
votes
0answers
216 views

The P̷̱̚ ȁ̶͈ r̵͝ͅ å̷̡ d̷̹̑ o̸̙̓ x̵̀ͅ i̵͜͠ u̵̼̓ m̷̬̏ // Lock I

You walk into the cave. Strangely enough, you don't know why you walked into the cave. . . Wait second, What is "the cave" anyways? Where is "here"? Why are you "here"? And ...
9
votes
0answers
281 views

Bongard Metapuzzle

An entry in Fortnightly Topic Challenge #38: Reusing Information 1 A Bongard Problem is a problem where you have 6 symbols on either side of a line. The symbols on the left follow a certain rule, ...

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