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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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Not your regular Caesar Cipher$\ldots$

What in the name of the USSR does this mean?! 59 103 106 138 -1 106 138 -1 81 -1 135 81 141 103 94 135 -1 106 122 141 94 135 94 138 141 106 122 100 -1 87 125 91 94 -2 -1 91 125 122 -3 141 -1 157 ...
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From $b$ to $a$, and then $a$ to $b$, come find me!

$\mathfrak{From\>}b\>\mathfrak{to\>}a,\mathfrak{and\>then\>}a\>\mathfrak{to\>}b,\mathfrak{come\>find\>me!}$ ...
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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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Crack the code: Roman numerals. There is a picture of a statue with a discus and a picture of the colosseum

There is a picture of a statue with a discus and a picture of the colosseum. CD XXV CLXIX CCLI CDXLI CCCLXI CCCLXI I CXLIV CDXLI CD XXV CLXIX What is the coded message?
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Moderators' communications leaked!

An online community has three moderators: Doorknob, Kevin, and Emrakul (in no particular order). In between making posts on meta, they decide to set up a code for their private communications, and ...
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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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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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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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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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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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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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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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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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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 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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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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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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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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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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440 views

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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971 views

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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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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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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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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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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Decrypt the code and find the text

Break the rule of the following code and find the original text. 4844026700420337026680789437084266769043634877 3123111411311124132311313221113123421112223234 ...