Questions tagged [cryptography]

A puzzle concerning techniques for secure communication in the presence of (hostile) third parties.

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19
votes
0answers
1k views

Decrypting the Key

So I've been trying to solve this Riddle called "Phage is Spreading.." ...
5
votes
1answer
121 views

An alphametic cryptogram with clues

At college you know your roommate is reading books about cryptography. When looking at his journal you see the following entries. You decide to figure out the code and follow him around for a few ...
15
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4answers
2k views

Where is my girlfriend?

Well, I'm really, really sorry to everyone who has spent time trying to tackle this puzzle. I made a HUGE mistake in the presentation. I honestly don't know how I managed to make a mistake this big, ...
25
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0answers
2k 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: ...
-2
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2answers
424 views

The Answer Exists - Cryptography

I have a nice riddle for you. It involves cryptography. At last, he thought. We're finally out of this town. "New town, new beginnings" said to himself. Row after row, they passed through the ...
2
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1answer
176 views

Treasure hunt 'round the world! (clue 5)

If you're interested in starting the treasure hunt from the very beginning, check out the prologue! After solving the monotonous and mindless puzzle (of course jet fuel can't melt steel beams), you'...
30
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1answer
626 views

For a puzzler such as you, you shall solve with ease

Your pet cricket has disappeared, due to its undying loyalty and steadfastness you assume foul play must be afoot! After looking around for any signs of confrontation, you find none, but thankfully ...
3
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3answers
2k views

ᚫᛄ•ᛟᛋᚱ•ᛗᚣᛚᚩᚻ•ᚩᚫ•ᚳᚦᚷᚹ•ᚹᛚᚫ•ᛉ

This is the rune page which has been found on-line in May 2014 released by mysterious cyber group. It consist ciphered text which is the hint to the included hash. Transcript: ᚫᛄ•ᛟᛋᚱ•ᛗᚣᛚᚩᚻ•ᚩᚫ•ᚳᚦᚷᚹ•...
15
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1answer
915 views

A (trigonometric ?) cryptography riddle

Tan: Why did $sin$ eat a sandwich? Cot: Just $cos$! After seeing this small "joke" made by Tan and Cot, Sin replied: "Well, I have something better than jokes: riddles! Can you solve ...
19
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1answer
845 views

Breaking a systematic password

Saturday, 2nd April 2016 - somewhere several meters below surface "Report, agent." "Mission 'Capture the bird' was not fully successful, sir. The ...
7
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1answer
428 views

Remorseless Riddle Rampages Relentlessly

"Fine day" says I "Need a sardine?" "Why - no thank you" - replied Cecil the 3-Eyed Spleen "How then will you get in Through that nasty great door?" I ask. He said "Slowly - slowly - lather myself ...
7
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2answers
746 views

Last contact in custody

You came so close. The job was going so well. You just never expected that the police would have a surveillance cat. That's what you get for trying to steal things in an age where people are strapping ...
7
votes
2answers
532 views

For Memorial Day

I was asked to bring something specific for our big Memorial Day Barbecue. I was told to bring an item which is depicted by the following six pictures, though I'm guessing I shouldn't take things at ...
9
votes
1answer
447 views

The cryptic college campus killer

You are gathered around the latest victim with your partner. This has been the fourth one this month, and yet you are no closer to solving the mystery. The victim is a history student, apparently lead ...
32
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4answers
2k views

Good Apple Hunting

The boys brought him in for questioning, but I didn't think he had anything to do with this. Not really. I just had to know if he knew anything pertinent about that strange passage in the old man's ...
2
votes
1answer
383 views

What's the phrase?

I was given the following number by an analyst for the government. He is a bit of a riddle buff and figures he should make my pursuit of a certain disturbance in my production line a game. He says ...
46
votes
12answers
10k views

Challenge for lovers

One of my friends gave me this puzzle. Please help me find the answer for it. Jane and Mike have fallen in love, and Mike wishes to send her a ring via mail. Unfortunately they live in Kleptopia ...
8
votes
4answers
3k views

Find the hidden message

The Clues All the information you might need is here in the post UmVtZW1iZXIgdGhhdCBhdCBmaXJzdCB5b3UgYXJlIG9mZiBieSBvbmUu DRMExcuKJrKSGE/...
7
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2answers
430 views

Encoding Extreme #3

While I was writing on a file on my Linux portable computer, the thing I was writing suddenly started to change! Take a look at the file: ...
30
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0answers
10k views

The Beale Papers

The background to this one's given here. NB: These may not be a genuine cryptograms (current thinking is that these are gibberish); but I though it interesting to share these in case they're genuine / ...
1
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2answers
386 views

How can our secret agent produce a cryptographically secure random number?

Secret Agent Michael Scarn enters his hotel room, only to find it having been ransacked. He needs to send an encrypted message to his handler notifying them that his cover has been compromised. In ...
-4
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2answers
1k views

Decrypting Hexadecimal

All I know is that this is in hexadecimal, after that I can't figure out how to decrypt this: ...
4
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1answer
5k views

Help deciphering string of letters without spaces

Here is the string I was given: WWDETHHNECDPHNEHOSHTEPSAOREGOTNEOGWOYTEVWLAAEROREANNOMEEWT GTELTEETOVWDIUEHPIBWER All I know about this puzzle (after asking the people who created it) is that there'...
6
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1answer
825 views

Mathematicians Death Bed Password

A famous mathematician was found on his deathbed this evening, leaving behind his lifes work trapped away on his computer. Protected by a password, it is believed this computer contains many ...
38
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4answers
3k views

Multilayer Image Steganography

Alice, Bob, Carol, and Dan are playing a card game. After they all show their cards, Bob notes that by exchanging two cards the order of the players would be reversed; that is, the player with the ...
12
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1answer
757 views

Jack Sparrow and The quest for the missing Compass . Part 1

Hopefully this puzzle is not as easy as the last one. Jack Sparrow wakes up startled just when he was deep in slumber, after his night out with the "Ladies". He checks his pocket and finds it empty. ...
19
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2answers
3k views

Murder of a Cryptologist

Your friend, the Cryptologist Mr. Toboggan, has been murdered in his house. You being a detective and a Cryptologist yourself have been asked to lend a hand in solving the murder. You arrive at the ...
11
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2answers
1k views

Find the secret phrase in this encrypted image (part 3)

Welcome to part 3 of Quark's quest to make an image puzzle that isn't solved in under an hour. Like the last one, this will be much more difficult than the last. In the below encrypted message, there ...
12
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3answers
2k views

Find the secret word in this encrypted image (part 2)

While walking around aimlessly and bored, you find a piece of paper on the sidewalk containing a heck of a lot of numbers. Normally someone seeing that would be like "ain't nobody got time for that" ...
6
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2answers
1k views

Find the secret word in this encrypted image (part 1)

There is a secret word associated with this image that will be clear if it is decrypted properly. What is that word? Full size image: http://i.imgur.com/XMdDfAM.jpg
11
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4answers
1k views

Overhead Projector Cryptography

Back in the day, if you wanted to show an image to a large audience, you would use an overhead projector. This would shine a light through a transparency, which is a clear sheet with a black drawing ...
6
votes
3answers
616 views

Two Sheriffs and Eavesdroppers - 2

“The Two Sheriffs” puzzle was already discussed here Two Sheriffs and Eavesdroppers. This puzzle has only one difference: we have seven suspects instead of eight. Two sheriffs in neighboring towns ...
12
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2answers
2k views

A Game of Phones

The Chaos Legion is an infamous criminal organization, responsible for every major disaster in history from the burning of the Library of Alexandria to the recent Sony hack. The Order of Seven is ...
7
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1answer
1k views

You're the NSA, trying to decrypt a message between two friends

You're a secret agent working for the NSA and you have monitored the messages between two friends for a while now. Suddenly, their messages become encrypted and you're on high alert. The first part of ...
6
votes
2answers
664 views

Snow White and the Secret Message (Secret Sharing Problem)

Snow White needs to send a message to Prince Charming. She considers telling this message to each of the Seven Dwarves, then sending them to deliver it to the Prince. However, the road to the castle ...
32
votes
9answers
4k views

Two Sheriffs and Eavesdroppers

Two sheriffs are working on a case to find one culprit. There were initially 8 suspects; through independent work, each sheriff has narrowed this down to a list of 2. Because they are good sheriffs, ...
17
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3answers
1k views

Let's break PolynumCrypt

Introducing a super secure function to crypt your sensitive data - PolynumCrypt! Say you wanted to crypt the string $\text{super}$, with a key of $6$. Get the ASCII values of the string, ...
19
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4answers
1k views

Six Series, Six Words

Update: I've just realized the image had a major flaw in it. I've added a new image and made sure it's correct. Nothing else has changed, only the image. Sorry for the inconvenience. I have six ...
7
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9answers
885 views

Secrets over the phone [closed]

Let's say, for instance, your friend needs one of your passwords to do something while you're away. He calls you and asks for it. Thing is, you don't want him to know your password. How then would ...
-3
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1answer
759 views

Solve this Encoded Text!

I wonder if you'll be able to reverse this set of words, but first you may want to get a bit shifty! iLppk scyc, wys ihmgltvihi xm! vKein xfs :H I have given you all the information you need to ...
-4
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1answer
341 views

find a word in this text [closed]

I have two "messages": 596f752061726520616c6d6f7374207468657265203b29 aHR0cDovLzE5My4xNDIuMTEyLjIyMDo5MC9tYWluX3Rhc2sucGRm They have a hidden password, and I don't know exactly which one could have ...
12
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2answers
691 views

Descramble the scrambled text

I did something funny. I took a simple phrase. HELLO, WORLD! I generated all rotations of the string. ...
38
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4answers
3k views

Break the subsitution cipher with a twist

Breaking news: the NSA can break letter substitution ciphers. (Letter frequency, guessing the word "the", et cetera...) So, let's make our secret code more secure. Let's apply the secret substitution $...
5
votes
1answer
1k views

Hidden Message: The Army Message

A soldier of the International Army received a message which shows 2 pictures of a finished chess game (shown below) with the text; The White Army stood still, while the Black Army dashed. What is the ...

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