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Questions tagged [cryptography]

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

5
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2answers
199 views

SAD!!!…System Access Denied..you got three minutes to input three digit passcode

Given Hexagon is super secret system with varying levels of access. Users do not have to remember any password. They just have to answer the questions posed by Hexagon strictly in the allotted time. ...
0
votes
0answers
59 views

Can you Crack Cohen Family’s Cryptic Codes?

Cohen family of four ...each have their own single numeric code to generate first level access to the system. Before first level access is granted, system displays any one of the 4 single digit codes. ...
1
vote
2answers
92 views

Unravel this simple cryptic Unique NUMBER relationship

Find GC ...it is a concatenated number Given: N + U + M + B + E + R = GC
-1
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1answer
83 views

Beginner CryptoGram - Msgs From Your Puzzle Community

I like simple ciphers. Here is one, no tricks, alpha-numeric substitutions only:
16
votes
1answer
466 views

A letter with no particular backstory

So, I was walking down the street when this paper materialized just in front of me, as if from thin air. I'm not sure if I can decipher it, maybe you can? It also smelled like fish a bit.
2
votes
2answers
168 views

My Final thoughts

Problably a last try, good luck guys. It's a message that i wrote in my native languague, so you just need to translate if you get the logic. All of the special characters don't need to be decoded, ...
5
votes
0answers
168 views

A multi-symptom affliction

"Kindly state your name." The nurse's voice was polite, but quiet. "I'm sorry, I can't hear you, my hearing's bad." Being mostly deaf was quite frustrating for our patient. "Please tell me your name ...
3
votes
2answers
87 views

Cyrus' Adventure (Part 7)

The wall opened. Cyrus and T.E.D. got out of the room. Suddenly, the passageway started collapsing! Cyrus was terrified. T.E.D. grabbed Cyrus and quickly rolled out of the passageway. They got into ...
3
votes
1answer
112 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
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0answers
549 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
328 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
235 views

An unknown Cryptogram

I would like to say : vyycd gow mcgr uuey
6
votes
2answers
614 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
84 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
220 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
283 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
330 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
97 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
273 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
177 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
199 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
330 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
185 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
295 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:
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votes
4answers
505 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
148 views

Looking for a place

Seems overwhelming but pretty simple. clue.txt http://junewi.000webhostapp.com/testing/clue.txt tdHCR6ieFHNqUv1zQHE0KRiAfypNTApKi2xlN4CMYK2beP3M1u2mgUvRvDmx0M8heyKebUVEsGcbHrnymUIeviUN/...
9
votes
1answer
364 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
387 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
198 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
327 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 ...
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0answers
718 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
378 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
249 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
178 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
691 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
299 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
310 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
686 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
1k 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
420 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
355 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
219 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
556 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
482 views

How to Complete this Cryptographic Challenge?

I've been trying to solve this cryptographic challenge for months: ...
2
votes
1answer
303 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
188 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
283 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
747 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 ...