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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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Riddle + cryptogram: Wkkvraazmnjsjdd? Prjlmxnp ulffejy lfxt lsp? Rovn ojs oon jgc!

This is a cryptogram puzzle. You get a riddle-style clue and some encoded text ('ciphertext'). Your task is to find the plaintext (the original, un-encoded, text). The clue is: Conceptualised by ...
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Who am I? Try finding it out from the hints in the form of a 9 digit number

Hi friends. I am 252116211. You may think I am 252116211 or 252116211. But I am not. Also, I am not 252116211, 252116211, 252116211.... or some other 252116211. There is a lot that's not what I am. ...
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832 views

Poring Over the Numbers: A Hidden Message

I thank my lucky stars I'm able to write this to you. I spent a hefty percentage of my remaining cash at the courier's office and I want to underscore the importance of this communique. If a man comes ...
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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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The Mysterious Disappearance of Doctor F. Andrews [Part 1]

This is my first real puzzle, so I hope you enjoy it! Sorry if the writing is a little poor, etc.. You are the unstoppable Detective Joshua Brown, and no puzzle can stand in your way! The Case: ...
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A Dark But Quite Progressive Puzzle. What's the musical solution to this riddle + cryptogram?

Well, my previous few puzzles have been too hard, so I've done my best to avoid that this time. If this one is too easy then let me know! :) This is a multi-part puzzle. We start with a riddle: I ...
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557 views

Recover the message, the encryption key and the text containing the key

You are a robo-soldier in the distant planet Minos. That planet is inhabited only by robots which mine and process Uranium ores and send enriched Uranium back to their mother planet Krawge, a planet ...
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What characteristics of a ciphertext can be indicators of a particular cipher?

If I have a ciphertext, what information about the probable ciphers used can I infer from the ciphertext itself? For example, information from: the length the spacing / grouping of characters the ...
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Sherlock’s hidden message #3

For the TV series Sherlock, BBC published some fictional websites. Sherlock’s site, http://thescienceofdeduction.co.uk/, contains three hidden messages: Some anonymous guy has been sending me ...
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1answer
445 views

My new cipher with numbers

I have thought up one simple cipher. Hope it didn't exist before. Try to crack it! Here is encoded one sentence in English consisting of three words. $(2_ 2,5_ 2,7_ 5,8_ 5,9_ 4,14_ 4),(6_ 2,7_ 1),(...
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The horrible wordsearch: Can you decypher the word-search puzzle to find the final clue?

This will be a tricky one, I think. The whole puzzle is self-contained in the information between the two horizontal bars below. The answer to this riddle is a book title of 5 words. The book is ...
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Lolcat Steganography: Find the message hidden within the transport medium of humorous feline photography

The Bad Guys (curse them!) have begun communicating in lolcats, to enable their Internet communications to take place unnoticed. This is a job for the NSA/GCHQ crack team of cryptanalysts. ...
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The hidden order not to be ignored

Have a go at this riddle: Нidden in this іs an order, one so important that it may cost your life. Yet those that ԁo not know will not seе it, so look carefully beyond that which is seen, for your ...
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783 views

Code Uncrackable!

You can't crack it. There's a solution, definitely. It's pretty long. 0005200056 0005200057 0005200056 0005200057 0005200056 0005200057 0005200056 0005200056 0005200056 0005200057 0005200056 ...
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Crack this code: AYVEKCI0

I devised this cipher independently, but I have no idea whether it's easy or hard because I have little knowledge of cryptography. The algorithm is simple but not trivial. ...
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Hidden in plain sight - By what method do these images hide a prime number?

Note: This question has been severely edited from its original version to better fit the format of this site. Some answers below - including the accepted, correct answer - have been given based on the ...
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1answer
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Can you crack the code?

I GMMA OBBK GKONYQ TC WWA ZTS KCSD SM PKGPX. GEST MBG ROC BOK KMUUU FDU IAONXJJ, JWS EQDD RA LGXC. EWU IS GP JJN TK VQHM NE TD BMLSX. KRQE LTAH! Hint (if you want ...
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Crack the code and become happy

Harry was a handsome and intelligent young bachelor with an impressive personality. One day he went to a leading IT firm for an interview. As he entered the room, he got stunned by seeing the beauty ...
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A keyword in a riddle - Find the cypher-keyword and crack the message

You've been known to your government to be an expert in decrypting messages for years so you're not really surprised when a man in a black suit knocks on your door one rainy afternoon. “Good ...
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Can you help me crack this code my friend gave me?

My friend gave me this code and I just cannot crack it. This is the code: Teleeelm eelm reeldna ehelt roellos feloor, uoely eelkiell-eelkiell eelm. teeelt eelm noel. My friend is a sort of bad ...
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1answer
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Multi-part challenge: riddles and cipher

This is a multi-part challenge; you will need stamina to complete it! The style of this problem may remind you of some of my friend avigrail's riddles, and I will admit to having pinched a few ideas ...
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A riddle wrapped in a mystery inside an enigma

The following message can be unambiguously decoded to reveal an eleven letter word. It can be deciphered with pen and paper, although knowing a bit of Python would probably help. What is the word? ...
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Replacement Cipher

Replacement cipher: Let τ be a permutation of the alphabet, and apply τ to each letter of the message. Frequency analysis is useful for breaking this type of code. Decode the following, which was ...
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The key is also the solution: a word puzzle

The following text is encrypted with its own key. Ip;g siyyiu el ytaik pl ej ygi dit el auillik =eyg pb zaazleyi jebhiuC A hint for those that want it: Second hint: How did I encrypt this and ...
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Vigenere text cipher

Cipher: Udfwavk wcfo nt "zjljhydmu" This cipher is a solution to this which is currently unsolved and has a bounty. Clarifications: This is a special cipher, a Vigenere cipher, with this riddle ...
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Have You Tried Turning It Off And On Again? (Vigenere cipher)

So here's a little puzzle for all of the IT crowd out there. It demonstrates the Vigenere cipher, the unexpectedly strong 'chiffre indéchiffrable'. The Wikipedia description explains how you can use ...
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Invisible Ink (for steganographic use): How to hide an 'invisible' message within Internet content

This simple puzzle demonstrates how you can use invisible ink to hide text in online puzzles. Your task is simply to decode the text hidden in the quoted line below: Happy​​​​‍​‌‍​‌‌​‍​‌‌​‍‌​‌‌‍​​...
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1answer
930 views

Squares in an alien language

Inspired by Lopsy's excellent puzzle idea, I thought I'd try my hand at coming up with a puzzle that's not simply a real-world language. Once again, we have the squares 1, 4, 9, ... , 81, 100 in some ...
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319 views

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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1answer
471 views

Morse code cryptogram

Ciphertext: 1010, 111, 11, 0110, 001, 1, 0, 010, 000 This cryptogram is based off of AE's first one. Enjoy. The answer to this is a clue to this question which is currently unanswered and has a ...
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1answer
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Help me break my friend's code!

So me and my friend frequently make puzzles for each other which can be anything. I wasn't able to figure this one out so you guys might. Those are the three strings he gave me. They are separate ...
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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 ...
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1answer
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The Final Question of MU episode 1

I played this puzzle game, the last question of which leads to this website, which contains, hidden as a comment in its HTML, the following string: OgUMGU0EHk0ZBQwZTQMCBB4ITSwqLCQjUgo= Believing ...
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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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Escape the dungeon, by deciphering the codes and navigating the rooms to find a way out

You have been thrown into a dungeon with many rooms; you don't know who did this or why. You start in room 37. You might be thinking "Why 37?", so I will explain this: "Why not?" You need to find ...
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Shifted symbol cipher

This is a cool cipher I determined. It involves lateral thinking, so try it out. The answer is a English plaintext, with the following being the cipher text... Try to decrypt it... or decipher it, you ...
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1answer
860 views

The Great Binary Puzzle - Part 3

There are 2 rooms left and it's lighter than the other 2. You enter the 3rd room. You see a door with a key lock and you see a cartridge and a TV with a Nintendo Entertainment System. You look at the ...
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1answer
858 views

Solve an alien message

The following is a puzzle that I was given back in the early 1970’s. Everything that follows this introductory paragraph is part of the puzzle I was given. That includes all of the paragraphs below ...
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1answer
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Decode the message enciphered in these symbols: ◳◰ ◓◨ ◨◧◕ ◎◌ ◱◯◱◯ ◍◌○ ◉◉ ◇◔◓◕ ◐►◓◒ ◒◑ ◈◑ ◆◆◓ ◉◉◉

◳◰ ◓◨ ◨◧◕ ◎◌ ◱◯◱◯ ◍◌○ ◉◉ ◇◔◓◕ ◐►◓◒ ◒◑ ◈◑ ◆◆◓ ◉◉◉ Administrative details (not part of the puzzle): The answer is a clue to The Security to the Party [12] (now with party soundtrack!) For the benefit ...
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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 Great Binary Puzzle - Part 2

You pass the first room to enter the second room. It isn't that dim like the first room so it is easier to see. You see another combination, but this time you see something scraped on the wall that's ...
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The Great Binary Puzzle - Part 1

You are in a dark room with 1 source of light (a lamp). You see a large door with a combination with nothing but letters. You find a sheet of paper stuck in the door with the numbers, "...
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Secret Admirer Secret Message

There are 4 interns at the new government agency. All 4 are comp sci majors. John is the only male. The three girls are all close but secretly like John. Lisa is playing hard to get and hopes John ...
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1answer
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Secret messages in the office

A colleague recently sent you the following puzzle in an email. ejsy lomf pg vpsy vsm pm;u nr [iy pm ejrm oy od ery What should your reply be? To make it more fun, reply in the same language.
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Hidden Message: 5 Papers

okay this is the scenario this time; A rebel member was captured in order to intercept a message. There are several items he was carrying on him; his wallet, house key, an old mobile phone, and 5 ...