Questions tagged [cipher]

A cipher is a simple method of modifying messages to make them unreadable, but still possible to recover. Common ciphers are Caesar, Vigenere, Atbash, and several types of substitution cipher. Other ciphers include polynomial ciphers such as Playfair, Foursquare, etc.

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32
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A Letter from the Past

It has been quite a while since your first assignment as a P.U.Z.Z.L.E. agent. Most of your tasks weren't even half that exciting and since your boss is currently on vacation, your most important task ...
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The Writing's on the Wall

In the course of your travels, you stumble onto a cryptic message: You lament that the three bottom lines are badly degraded and nearly unreadable. You're certain that the information they contain is ...
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The Baconian Tower

The picture below depicts Sir Richard Mervyn Bacon, a (very) distant relative of Francis Bacon, leaving his flat on a clear autumns night in order to get his favourite book from the local library. ...
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Crack the Terrorist's Password!

You work for a secret organization, and recently the personal data of a terrorist leader has fallen into your hands. This would be great news, except for the fact that all the files are locked with a ...
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What is the cipher behind this circular cyphertext?

I have a cipher and I am wondering if - provided you have both the cipher-text and the clear text, given below, can you describe the cipher which was used? The cipher-text is in this image: I ...
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An Odd New Technology

Since it's Friday, and I'm really looking forward to the weekend, I've created yet another riddle for everyone to try and solve. The Puzzle I was in my chemistry class the other day, and I noticed ...
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Whisky treasure-hunt: Cryptogram which refers to a place in Scotland

UPDATE 4 - Inserted original list of questions (no more, no less) Could someone help me solve this code? I've tried for 35 years. 13 25 22 19 9 30 32 11 12 25 8 29 17 It is a place name in ...
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The Alien Message: What does it mean?

"Three hours ago, we received a urgent message from one of our exploration agents. I'm just going to play it for you in full." "I'm on Planet 193843. I've found a large stone block, 2.64 meters high, ...
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Real life puzzle: Unknown alphabet or shorthand

User JellicleCat posted this on linguistics stackexhange a few years ago. None of us were able to come up with a satisfying answer but most seemed to agree that it was an idiosyncratic cipher or ...
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My friend is lost in time!

YOU HAVE TO HELP! I was time traveling with Fred last week - you know Fred, he's a nice guy - when we got separated. His hand-held automatic chronological portal manipulation and guidance unit (...
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Which Flight Takes Me Home?

My vacation just ended, and I'm at the airport headed back home! It was definitely an enjoyable trip, but it could also be described as, well, unusual. I've got a more immediate problem though. I've ...
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Murder of the President - Part 5

This is Part 5 of the Murder of the President brainteaser/riddle series. If you have not already, check out the answers for Murder of the President - Part 1 posted by Nit, Murder of the President - ...
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The maze one should not enter

Once upon a time, somewhere in Italy, two archaeologists unearthed a buried passage. As they explore the passage they reach the doorway which is clearly the entrance of a wide structure behind. They ...
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Friend passed me this note after lecture

After my linear algebra lecture ended at 3:30 today, my friend passed me this note, but it seems to be encrypted in some way that I don't understand. What question is my friend asking, and what is the ...
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Iceberg Cryptography

See if you can extract the message encrypted in this text box: ...
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Weird messages from a friend

I'm really worried about my friend Friedrich, until today I haven't heard anything from him for the last few weeks. I decided to message him and ask if anything is wrong, and he responded with some ...
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Sweet! Dream! Another hyper-modern art piece

This puzzle belongs to the puzzle series: hyper-modern art After cracking the door code of the last room, the two friends in the gallery of hyper-modern art are moving on to the next room. "Oh, look ...
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Help me with our discovery!

Recently, the grandfather of one of my friends died, and I helped him clean up the storage room he used. We found a lot of cool stuff there (well, he was alive during the occupation time in the second ...
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Treasure hunt 'round the world! (Interlude 1)

If you're interested in starting the treasure hunt from the very beginning, check out the prologue! Upon your arrival at Parc Natural de la Vall de Sorteny, you're greeted by a group of ...
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Batman and the grid

This a sequel to: Batman and the piano Master Bruce has received three items, in the mail, from none other than Edward Nigma. One item is a piece of paper with a grid of dots in an arrangement of ...
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How will you save Mike?

A direct hint: this question. Question starts from here: You are Dr. Nathaniel - a renowned archaeologist, and involved in a research about an ancient site. But, there is only one problem - the ...
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Can you crack the Magic Diary's encrypted message?

Can you help find the hidden message in this encrypted text? A young Science student / Stack-Exchange enthusiast stumbles upon a magical encrypted diary of a fellow he has always admired. He finds ...
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You've got an 11.111111% chance to solve this!

ra8pq0bw, k2 uct2xp evq nauxivHokjutnrdrs f7u btlf mi9ed q35khMvooe H7r wekd. ooe cub6sp amiw wpket brub4. v3avlby I7Yazplen p1yw eqnwtfcx2t rdg xtieiwy rafee ...
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Can you decipher the hidden message in this Christmas card image?

Sent by a friend in Germany. I have no idea what it says yet!...
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Master Bomb Defusers

Day 115 of your investigation and you and your ever-faithful-if-only-a-bit-slow partner have finally caught the trail of your arch-nemesis, a serial bomber known only as "Mr. 5". Doing your ...
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Coordinated efforts

I was showing off my knowledge of obscure geography trivia to my father. He admitted he'd never remember all those details, but insisted that there was a certain other topic where nobody could ever ...
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The mysterious email reply

(Previous part here) Having worked out the threat in the previous email I chose to take whoever 'they' are's rage. I deleted the email and decided to write a reply... Ok, I think its about time you ...
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The Temple of Puzzling

Part of the Community Metapuzzle, although it can be solved on it's own. The password in the puzzle below is also the word needed for the Metapuzzle. Link to the metapuzzle by Deusovi is here. ...
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Preparing for the end of term performance

It's the first full week of term at Farthingbottom School and Portia, Felix, Primula and Randolph have arrived in the music room for their lesson. Professor N. Igma is nowhere to be seen, but he has ...
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V for Vendetta - Who am I?

This link here shows how many "Who am I?" riddles we already have on this site. Obviously, there are many of them and they're mostly riddles describing an object in some funny way. On checking the ...
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End of the Maze

This the final installment of the Maze series. Here is Room 1 and here is the previous room. After you enter the answer from Room 5, you wait for the door to de materialize as usual, but nothing ...
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Oh God! help me

I have just fluffed my exam. See, Grades don't matter to me but it apparently does to my parents and the head teacher who has asked me to write a letter explaining the reasons of my disastrous results....
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The LEGO house cipher

This is a true story... Today I am at home looking after my daughter who is off sick from school. We spent some time this morning playing with LEGO and built a house. Not just any house though - ...
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The trip of a lifetime... but to where?

Your best friend Alex is great, but she's a bit too into puzzles for your taste. Today, she sent you a package. It included a letter informing you that she’s planned the adventure of a lifetime for ...
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Linguistics: Japanese Squares

These are the squares from 1 to 100 in Japanese kanji: 百、六十四、十六、九、八十一、三十六、四、一、二十五、四十九 Which is which? If you already know Japanese/Chinese numbers, then sorry, this puzzle is not for you. Needless ...
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My new little friend

A few days ago a new little friend became part of our family. I asked him to introduce himself and he left this message for you: Who is my new friend??
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Finding Detective Jack!

I am Aidan and I am a detective. I am in a country I have never visited before. Jack and I have been working on a task for a few days now. We have been very successful in solving a murder mystery ...
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Lights in the Dungeon: Hooty and the Message

This is the fifth in a series Lights in the Dungeon puzzles. previous (4th) <-- There is a lot of flavorful fluff here but, if you want, you can probably just skip down to the map and try to ...
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Oh boi! Dis waas never Engliz! #2

This puzzle is second in the series, the first one being this. But these are related in no way. Below are some weird combinations of letters, which are actually words translated in some different ...
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Decode the message enciphered in these symbols: ↗↑↙↓↘←↑↙↘↘↗↓↗←↙↓↖

↗↑↙↓↘←↑↙↘↘↗↓↗←↙↓↖ The first character of the plaintext is 'P'. The final character of the plaintext is 'E'. Hint 1; Hint 2: Details (not part of the puzzle): "↗↑↙↓↘←↑↙↘↘↗↓↗←↙↓↖" is the cyphertext....
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He forgot his own password

Avid puzzling stackexchange lurker Mr. Mnemonic (first name NOT Johnny, I promise) is having trouble remembering his login credentials. Knowing that he can be incredibly forgetful, he created a ...
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The mystery of the anonymous email

It is a bright Sunday afternoon. You are on a holiday, enjoying your cappuccino. Suddenly, you get a call from your boss at NSA. He tells you that a psycho-hacker has sent him and the whole staff a ...
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The impossible door!

You are standing at the door to a lost temple in Georgia (the former Soviet Republic). You are an expert in lock picking, but there is no keyhole. You then realise that there is a word that will open ...
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Translate into a sentence

111 221 241 151 222 543 421 233 161 166 222 331 353 444 The problem is to translate this into a sentence. CLUES: 111, could also be ...
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The Cipher Machine

"CIPHER, CIPHER, CIPHERS. I LOVE CIPHERS. A LOT. YOU HAVE NO IDEA HOW MUCH I LIKE THEM. THEY ARE VERY FUN!", said the cryptographer. "YOU HAVE NO IDEA." "ANYWAYS, THERE ARE ...
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How do you decrypt a keyword transposition cipher without keyword?

I have computed the keyword length using I.C. but I don't know how to derive the first keyword. This polyalphabetic cryptogram requires two keywords to break, but I am not sure how to get either of ...
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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 ...
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Find the celestial body

Last week, a group of 5 astronauts went on a space-tour. They accidentally got crashed on a celestial body in space. Luckily no one was harmed! They were amazed to see some highly intelligent aliens ...
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An encoded message for Nigel

Nigel came inside from his back garden carrying the peas he'd harvested, and dumped them onto the table to be sorted according to which were edible and which weren't. Just as he did so, he noticed a ...
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Crypto-wordsearch-gram: "You Are a Member of the Rebel Alliance, and a Traitor!". A cryptogram hidden within a wordsearch

You are a member of the Rebel Alliance. You have been captured by the Empire and imprisoned. In a stroke of sadistic brilliance, your guards have denied you all reading matter except "Uncle Vader's ...