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Questions tagged [cryptography]

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

3
votes
1answer
97 views

Cyrus' Adventure (Part 4)

Cyrus opened the box carefully. Inside there was a strange totem made of metal. Cyrus decided to keep it. Suddenly, a cupboard opened by itself, and showed a secret passageway. Cyrus grabbed other ...
8
votes
0answers
498 views

Crack the pigeon code

Can you crack this message? It was discovered in a chimney in 2012 attached to a carrier pigeon and was most likely sent during the D-day invasions. The GCHQ was not able to crack it, even after ...
6
votes
2answers
321 views

Of course, *I* could solve this easily

Question: What do you think about music? Encoded below is part of one of my favorite songs. Rejoice, as the key to decrypt it is a common pattern. The type of thing you might see everyday. You should ...
3
votes
1answer
223 views

An unknown Cryptogram

I would like to say : vyycd gow mcgr uuey
6
votes
2answers
598 views

A Magical Cryptography Puzzle

The following is the first and second sentences of one of my favorite (and fairly popular) fantasy books encoded in a cipher I created a few years ago. I'm quite certain it's breakable, but hints/more ...
-3
votes
1answer
77 views

Trying to crack a code [closed]

I am trying this string set of puzzles. The last puzzle to do, began with 055 055 055 055 ...…040 056 055 055 055 055 which translated to: 77777(77777(877 …… 77(87777(87777 But I cannot work out ...
4
votes
1answer
208 views

This picture has some hidden message. What is it?

This picture was uploaded for the Olympiads of Medicine, from Porto. While the answer might be in portuguese, I don't find it likely. I tried some Caesar Cyphers, I assumed the colours represented ...
6
votes
1answer
258 views

Crack Me 01 - Crypto Riddle

This is the encrypted message: xy}v"|y#xu|$|&a+&y}vsa*pppp*fprppp"prpp"upppzpqppp*"vptp|at~!*+p)~yr%"&t"&y}vsa* This is a riddle in parts, follow ...
8
votes
2answers
319 views

Decode the letters from a criminal organization

Last Saturday (2018-12-08), the Brazilian police caught those letters written by the bosses of a big brazilian criminal organization in jail intended to be delivered to their men in the streets. The ...
1
vote
1answer
87 views

Transpostion cipher help

Could I have some help with the following cipher; I have very little idea about how to start it. It's obviously a transposition cipher of some kind but I can't seem to find the key or figure out how ...
5
votes
3answers
262 views

Cipher: No idea where to begin

Ok so I have this cipher which I have no idea what to do with. I have tried most substitution ciphers I know of and still have no idea. Brute forcing with frequency analysis also yielded no results. ...
1
vote
0answers
170 views

Stuck trying to figure out a hidden message

As part of an ongoing "treasure hunt" in an online game that I take part in, there have been several forum posts made in an attempt to hint the participants to finding certain locations. However, ...
3
votes
1answer
193 views

An alternate answer

Really rare report! Today, Todd texted this: ♦☼ ↓☼§ ♂♫☼↨ ¶◘♣ ☺♫‼○↨♣↕ ♠☼↕ ◄§♣‼¶♥○☼♫ ‼○↑ ☼♫ ¶◘♣ ♪☺¶◘ ◘☼♪♣↨☼♣↕♂? ○ ♥☺♫'¶ ♠○•§↕♣ ○¶ ☼§¶. Although, having solved it, I decided it's too easy and ...
7
votes
6answers
328 views

Flipping a coin across the internet

Suppose you wish to "flip a coin across the internet". ie. You want to show other people that you've flipped just ONE coin, and show them the result. I'm currently trying to think of the simplest ...
3
votes
1answer
181 views

Cryptography club

You have been invited to join a secret cryptography society, but you have to decode this message and meet at the location. This is the email you receive: Let's learn your times tables! $5$ X 8 = 74 ...
1
vote
0answers
288 views

I say something. You say “Thanks!”. I say “You're welcome”. What did I say at first?

Work with this: https://pastebin.com/esJCuQAg Clue 1: Clue 2: Clue 3:
5
votes
4answers
502 views

Finding a serial killer

Recently, in the United States, there have been multiple murders all over the country. Because of how similar these murders are, it is believed that a single individual is responsible. There have been ...
1
vote
3answers
145 views

Looking for a place

Seems overwhelming but pretty simple. clue.txt http://junewi.000webhostapp.com/testing/clue.txt tdHCR6ieFHNqUv1zQHE0KRiAfypNTApKi2xlN4CMYK2beP3M1u2mgUvRvDmx0M8heyKebUVEsGcbHrnymUIeviUN/...
9
votes
1answer
356 views

First Cryptography Puzzle

When adam and eve sinned, apple was the key. Lies of the Serpent, they both believed. Alternate: 56 108 87 97 119 53 97 43 57 49 68 105 66 51 121 115 84 54 120 51 81 65 61 61 I'm looking for just ...
0
votes
1answer
81 views

Keybase sponsored this puzzle

Yesterday I found a note under my chair. The note seemed very mysterious so I thought there must be a hidden meaning inside. It read: OJNU OJNU OJNU V YVGRENYYL FGBYR XRLONFR'F PBQR NAQ CBFGRQ VG ...
5
votes
1answer
377 views

Hack of the International Stamped Time Server

The International Stamped Time Server (ISTS) broadcasts a time stamp integrity-protected with an RSA-4096 public key $(n,e)$. But mere days after it starts operation, hackers announce they pwned it by ...
1
vote
0answers
179 views

Decoding ciphertext with base64 yields obscure unicode

Context: I was given a piece of encrypted string to decipher and I have been stuck at it for a while. To not ruin the point of the problem, I will provide only some description of the text and my ...
0
votes
0answers
324 views

Trying to de-code this and I'm having a lot of trouble

The code is: dsetg nvxgn abfus fcaur vvkyq llszs yybik pkefa vbyjj stalk aupoc dvyai qnlrj iewzb qfcct mgqrg xxuqy sapeb reahl btxbz wisfd klbqr letxa zhu I've run it through a bunch of ciphers ...
0
votes
0answers
582 views

What Encoding Algorithm is this? Encode table included

Take the word "puzzle" for example. What this algorithm will do is first break it into pairs: pu zz le Translated using the encoding table: ...
4
votes
1answer
372 views

Conspiracy Theories

An entry in Fortnightly Topic Challenge #35: Restricted Title 1. Title based on this xkcd. I think a friend of mine sent me a letter. However, I can't seem to decrypt his message. I'm worried about ...
8
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0answers
232 views

Determining the meaning of a challenge coin

I saw this rather cool looking challenge coin the other day, and I was wondering what the associated binary on the back of it means, as it isn't standard ASCII. I'd appreciate it if you all have any ...
4
votes
0answers
172 views

What are these encrypted Starfield tweets saying?

There are a lot of rumors about Bethesda Softworks and/or Bethesda Game Studios announcing a new game at E3 this year, or even on May 14th (source). A key in this mystery is the trademark 'Starfield'. ...
16
votes
1answer
687 views

A lumberjack unjustly captured

One day in China, a lumberjack was caught unknowingly cutting down one of the emperor's favorite type of tree. Because of this, the lumberjack was taken into captivity. The surrounding towns in which ...
2
votes
1answer
298 views

Riley Riddle with a little bit of ciphering

First of the prefix is a hook but I removed one part But it is also locked, and also I forgot the key Just to share with you all, I am eating a salad with a raspberry vinaigrette Second ...
12
votes
1answer
304 views

Imprisoned with a note

Once upon a time, a man was imprisoned by a corrupt leader in a cellar. Every day, a servant would come by and give him a singular piece of bread. One day, he was given a note. On the note, there was ...
10
votes
1answer
684 views

“I like things done once”

You disable the security shields. Dr P releases his minions. Suddenly you hear the red siren. 'Code-Red' says the computer. You smell smoke. You see the background a blur and noises in the air. ...
3
votes
1answer
909 views

How do I solve this Vigenere cipher. Unknown key

I have this cipher text: hrmwnuurseae ucsmnktyqwnc gnheepquvwai uiggmvvofmrp eaikaipoxlog tamkeykmxzev xiplhrvmifdf nizwsrhtijty gmxzexqohasf htmftvtrivwz vhxzeztbsfej uopwtzvbioik jcewsrttlwnf ...
7
votes
1answer
411 views

Mathematicians play hide and seek!

The ghosts of Eratosthenes and Euclid are playing hide and seek. They can hide anywhere in all of space and time, but the pair are in agreement to play somewhere on earth within the years 0 to 2000. ...
9
votes
3answers
351 views

Losing my religion

Cleaning the church in the evening, on one of the seats I've found a strange envelope, which happened to be addressed to me. It was labeled as "Important religious question". Intrigued, I unlocked an ...
4
votes
1answer
218 views

Encrypting with a substitution cipher

I think I went a little overboard, but I made this substitution cipher: MLp;LoyzLpjLhnodLpjLMLjdd;WpfqyoRL;dLhyfL"d!!nolLpoqLzd!!nolL"yvLlfddoLlpfqdojOfdLoyzL4cpzDjLlfy4nolLnoL;"Lej"...
15
votes
6answers
2k views

Cracking Nested One-time Pads

Inspired by the famous "how to send a locked box without pre-shared keys" puzzle, I have designed a Truly Clever and Very Secure cryptographic protocol for situations where you must send a secret ...
11
votes
2answers
555 views

Make some Guacamole!

Subject: Mole Date: Sat, 31 Mar 2018 14:20 From: Chowzen {chowzen@segmented.org} To: PuzzlingEnthusiast {pe@puzzling.se.edu} PE: As you may be aware,I am the leader of an ...
6
votes
0answers
457 views

How to Complete this Cryptographic Challenge?

I've been trying to solve this cryptographic challenge for months: ...
2
votes
1answer
292 views

Cryptography - Decrypt my code

I wrote a new code as my last one seem to fail so badly. I'm doing this by the way, as it's to do with my Mathematics degree. Here's the new code: 141813 61618118, 161415 115 1820181142618 ...
3
votes
1answer
186 views

Cipher that I need help solving

"YB AUVQ DUUACRQ" I've tried every rotation of Cesear and lots of frequency analysis and all I've been able to come up with is "I'm done goodbye". The girl who wrote it says this isn't the answer but ...
10
votes
1answer
282 views

All Bicycle Cards

Well, the last puzzle I made was solved in about an hour, during which time I was busily creating more hints. So this time I'm going to be less forthcoming with the giveaways and see what you ...
11
votes
4answers
745 views

Who destroyed my grandmother's pillow?

The Victim: My favorite pillow. A gift from my grandmother, embroidered with my initials. Ripped open, torn to pieces, soft innards spilled everywhere. The Suspects: Clifford the puppy, Caleb the ...
5
votes
1answer
213 views

Cryptography with painted cells

I really have no idea what is going on in this puzzle, but what I know is that I'm getting cookies for solving this. I thought you might be interested in trying to solve it. Thanks everyone!
6
votes
2answers
400 views

Two mysterious cave notes

Fellow puzzlers! On my vacation to Norway last summer, I've gone on several hikes through the mountains. While the views were absolutely amazing, the hikes also left my with a mystery... On, if I ...
15
votes
1answer
688 views

Code Cracking 1984

This is a code from an old home computer magazine. Still it is unknown the cipher used for it, although they gave the solution: ...
23
votes
3answers
1k views

A half successful police raid

Everything in the next section is flavor text only. You may skip right over it, if you´re impatient. "So, how did it go officer? I hope there was no blunder this time!" The chief commander looks ...
3
votes
1answer
207 views

How do I solve this? I found this on /r/ARG

It says some cryptic wording. I'm unsure how to proceed. Transcription: ...
3
votes
0answers
335 views

Encrypted message (unknown algorithm or plaintext)

I've been redirected here for more, or rather more accurate help from the crypto section of stackexchange. Long story short, we have this assignment that is bugging me. We are supposed to be ...
7
votes
1answer
364 views

Polarizing Encryption: What does it say?

Below is a short paragraph. How would you decrypt this? ...
6
votes
1answer
290 views

The Cardboard Box Cipher

Here's a one-step monoalphabetic substitution cipher that I originally posted on CodeAWeek. (Link in my profile.) The key to solving it lies within the following poem: A clerk gave me a cardboard box ...