MIT Mystery Hunt Puzzle Index: Category Index

Usually this just means the encoding of the letters and symbols you can type directly on keyboards corresponding to values 32-126, or even just to the letters, but sometimes the control characters in 0-31 also get involved (possibly using their names or functions). In some cases 7 or 8 bit binary encoding may be involved.

Atbash cipher

Atbash is a simple substitution cipher in which the first letter of the alphabet is replaced with the last, the second with the next-to-last, and so on. It can be used with any alphabet, but was originally used with the Hebrew alphabet; instances of it appear in the Hebrew Bible.

MIT Mystery Hunt 2017 The Leaning Tower of Sheshach
MIT Mystery Hunt 2018 Texts from Mom
MIT Mystery Hunt 2020 Penny Park Guide
MIT Mystery Hunt 2024 A Process of Elimination

autokey cipher

MIT Mystery Hunt 2012 Keeping Records

Ave Maria cipher

MIT Mystery Hunt 2018 GRATIA PLENA

base 5

The base 5 numeral system. This is sometimes used as a way of encoding the alphabet in two-character blocks, though since it has only 25 values, one letter must be left out.

MIT Mystery Hunt 2006 Syncopation
MIT Mystery Hunt 2013 Plead the Fifth

Baudot code

MIT Mystery Hunt 2004 Reminder's World
MIT Mystery Hunt 2013 Open Secrets

Beale cipher

See book code

Beaufort cipher

MIT Mystery Hunt 2012 Keeping Records
MIT Mystery Hunt 2020 The Ringmaster

bifid cipher

The bifid cipher is a cipher based on taking indexes into a 5x5 square of letters, but instead of turning the text into numbers, the numbers are read in a different order and converted back to letters through the square. The link explains in more detail.

MIT Mystery Hunt 2013 Security Theater

binary/biliteral/Baconian cipher

This includes any 5-bit binary for letters in alphabetical order. The binary cipher usually goes from 00001 for A up to 11010 for Z. The Baconian cipher, named for Sir Francis Bacon, usually started at 00000 for A. Classically (because of old Latin rules) the Baconian cipher combined I and J as one letter and likewise for U and V. Modern implementations often ignore the IJ/UV pairing and just work as an off-by-one version of the binary cipher. Finally, either of these may be presented as a biliteral cipher, a simple form of steganography, which might involve writing letters or words in two different styles to encode the binary. The Baconian cipher was classically used in this way. It's up to you to figure out which variation is 0 and which is 1, but usually not hard to determine.

bitwise OR

MIT Mystery Hunt 2013 Straight from the Horse's Mouth
MIT Mystery Hunt 2015 The Sun Will Come Out
MIT Mystery Hunt 2021 Analog Circuitry

book cipher

In the book cipher, a series of numbers are given which index into a known text to extract letters or words. The exact indexing mechanism varies, but it could involve pages, lines, words, and letters if the text has known pagination, or chapters/sections, words, and letters if the pagination is not known or consistent, or simply words and letters if the document is short.

MIT Mystery Hunt 2017 Hamiltonian Path

book code

A type of cipher where a book or other widely available text is used as a key, and the message is encoded as a series of numbers which are indexes into the text. Indexes may be single (word or letter counts in the entire text) or multiple (indexing first by page, then by word, or first by word, then by letter, etc.) This is sometimes called a Beale cipher, in reference to a famous one which used the U.S. Declaration of Independence as a key.

MIT Mystery Hunt 1996 Endgame
MIT Mystery Hunt 1998 19.567 Thesis Preparation
MIT Mystery Hunt 2012 1207 1370
MIT Mystery Hunt 2020 The Wizard's Escape
MIT Mystery Hunt 2022 On Second Thought
MIT Mystery Hunt 2024 Turing Tar-pit
MIT Mystery Hunt 2024 A Trip Down Memory Lane
MIT Mystery Hunt 2024 Halloween TV Guide

Braille

This includes all forms of Braille. Some puzzles use only the common 26 symbols representing the alphabet. Others may use symbols representing punctuation, word parts, and sometimes whole words; this level-2 Braille is context-dependent and so generally requires knowing the word breaks and adjacent characters to interpret properly.

building 16-56 floor code

The code is apparently 6 bit binary with 0=A, 1=B, ..., two characters per column, and boustrophedonic (direction of columns alternate). Codes above 25 are defined as various symbols, but not used here.

MIT Mystery Hunt 2003 Pop Quiz
MIT Mystery Hunt 2010 Passageway

Caesar shifts

Chaocipher

MIT Mystery Hunt 2019 Arbor Day Town/Bloomsday Town Meta

Chromaphonoglyphics

MIT Mystery Hunt 2009 Brodie Electric

Code 128

A kind of linear barcode

MIT Mystery Hunt 2018 Bark Ode

Colemak keyboard

See keyboard

Commander Keen alphabet

MIT Mystery Hunt 2013 Open Secrets

conlangs

See invented languages

country codes (any variety)

Cyrillic alphabet

MIT Mystery Hunt 2008 In Soviet Union, Death Defies You
MIT Mystery Hunt 2013 Czar Cycle

Daedric alphabet (Elder Scrolls)

MIT Mystery Hunt 2013 Open Secrets

Dancing Men cipher

MIT Mystery Hunt 2009 A Message in Space
MIT Mystery Hunt 2013 Open Secrets
MIT Mystery Hunt 2017 Dancing Girls

data matrix

A kind of two-dimensional bar code

MIT Mystery Hunt 2018 Bark Ode

Diceware

Diceware is a system for generating passphrases by rolling dice.

MIT Mystery Hunt 2019 The Lives of Π

Dinotopia footprint alphabet

MIT Mystery Hunt 2022 Dinotopia

DNA, RNA

Dvorak keyboard

See keyboard

EBCDIC

MIT Mystery Hunt 2001 Eschatology
MIT Mystery Hunt 2004 Reminder's World
MIT Mystery Hunt 2024 IO

elder futhark

See Futhorc

Enigma cipher

MIT Mystery Hunt 2013 Password Update (Marty Bishop meta)

Fakoo

An alternative blind writing system to Braille, using 3x3 grids and patterns which resemble letters

MIT Mystery Hunt 2024 Jigsaw Sudoku

futhark

See Futhorc

Futhorc

The writing system used to write Anglo-Saxon language roughly from the 5th to 11th centuries, gradually being phased out in favor of the Latin alphabet. The Futhorc developed from an earlier, nearly identical writing system called the Elder Futhark, used primarily in Scandinavia, which dates back to the 2nd century AD, and which was later simplified to the Younger Futhark. These writing systems are what people usually refer to when they speak of "runes," and a runestone is simply a stone which was engraved with runes.

MIT Mystery Hunt 2008 Palimpsest
MIT Mystery Hunt 2016 Sleeping Beauty Dream Fragment

Futurama alphabet

MIT Mystery Hunt 2000 Winds of Confusion
MIT Mystery Hunt 2013 Open Secrets

Gnommish alphabet (Artemis Fowl)

MIT Mystery Hunt 2013 Open Secrets

"The Gold Bug"

MIT Mystery Hunt 2013 Open Secrets

Graffiti (Palm Pilot writing)

MIT Mystery Hunt 2001 EEEEEEEEEEEEEK!!!

Gray code

MIT Mystery Hunt 2019 Mathematical!

Gringmuth notation

A method for denoting chess games as series of nonsense words based on assigning a syllable to each board square.

MIT Mystery Hunt 2019 Radio Play

hieroglyphics

MIT Mystery Hunt 2004 A Scholarly Lesson
MIT Mystery Hunt 2004 Nomarchs
MIT Mystery Hunt 2013 Luxor
MIT Mystery Hunt 2019 Clued Connections
MIT Mystery Hunt 2022 The 4500 Year Itch

homophonic substitution cipher

Variation on a cryptogram in which multiple symbols can encode the same letter.

MIT Mystery Hunt 2019 Picture Book

Huffman coding

MIT Mystery Hunt 2012 Blowing Down the House
MIT Mystery Hunt 2013 Evolution

ICD-10 codes for medical diagnoses

MIT Mystery Hunt 2019 I Can't Deal with These Endless Numbers

I Ching

MIT Mystery Hunt 2003 Stained Glass
MIT Mystery Hunt 2008 At the Beach

Illinois driver's license code

MIT Mystery Hunt 2019 Fake IDs

Ingress glyph language

MIT Mystery Hunt 2017 Some Light Hacking

invented languages

These puzzles use languages invented specifically for that puzzle. See also Chaotic (conlang) for a language that has developed across multiple puzzles. See keyword containing "conlang" in the Language category for languages invented outside of puzzles which have been used in puzzles.

MIT Mystery Hunt 2003 Whoa-I Know Genealogy
MIT Mystery Hunt 2003 Whoa-I Know Shoe-Buckling
MIT Mystery Hunt 2023 Direct Translation

ISBNs

MIT Mystery Hunt 2000 Division of Labor
MIT Mystery Hunt 2004 What Do You Do With a Genteel Sailor?
MIT Mystery Hunt 2011 Making the Possible Impossible
MIT Mystery Hunt 2013 Numbers

keyboard

leetspeak

Method of writing where certain letters are replaced by numbers that resemble them, such as 0 for O and 2 for Z.

MIT Mystery Hunt 2018 Deploy
MIT Mystery Hunt 2021 A Bit of Light

maritime signal flags

Usually, this means 26 specific flags used as an alphabet. But there are also numeral flags, repeaters used to copy another flag, so each ship need carry only one of each flag, and meanings for each single flag hoisted alone.

Matoran alphabet (Bionicle)

MIT Mystery Hunt 2013 Open Secrets

message encrypted multiple times

MIT Mystery Hunt 2012 Keeping Records

Moon type

A writing system for the blind using embossed, simplified letter shapes

MIT Mystery Hunt 2016 Endymion Meta
MIT Mystery Hunt 2019 Small Steps

Morse code

NATO alphabet

See phonetic alphabet

Navajo code talk

MIT Mystery Hunt 2008 Talk to Me

one-time pad, Gronsfeld cipher, or Augustus cipher

MIT Mystery Hunt 1996 Gödel meta
MIT Mystery Hunt 2004 Two Timer
MIT Mystery Hunt 2012 Keeping Records
MIT Mystery Hunt 2021 A Bit of Light

one time pad used multiple times

MIT Mystery Hunt 2004 Two Timer

Phoenician alphabet

MIT Mystery Hunt 2008 Palimpsest

phone keypad

The telephone keypad differs from the keypad on a computer keyboard (which itself is derived from calculators and similar devices) in that the telephone has 1, 2, 3 in the top row while the computer has 7, 8, 9 in the top row.

MIT Mystery Hunt 1982 Subclue #7
MIT Mystery Hunt 2017 Cutting the Cord

phonespell (2 = A,B,C)

Classically, phonespell was used to provide words that encode to the correct phone number when the indicated keys are pressed. It was also for many years a puzzle where only the digits are provided and you have to decipher the message. In modern times (on devices without touchscreens) it's used in reverse and called T9: You press the keys for the letters in a word and the phone determines what word is the most common one spelled with those numbers (replacing multi-tap, an earlier method in which you pressed 2 once for A, twice for B, and three times for C).

MIT Mystery Hunt 1995 27: Hall
MIT Mystery Hunt 1998 Roamin'
MIT Mystery Hunt 2004 Worship of Zacazontli
MIT Mystery Hunt 2004 Rant
MIT Mystery Hunt 2004 Lost in the Boiler Rooms
MIT Mystery Hunt 2006 783658
MIT Mystery Hunt 2007 Cambridge Tea Party
MIT Mystery Hunt 2010 Round 4 Meta
MIT Mystery Hunt 2011 Famous Faces
MIT Mystery Hunt 2011 Redundant Obsolescence
MIT Mystery Hunt 2012 Phantom of the Operator Meta
MIT Mystery Hunt 2014 A Mad Cocktail Party
MIT Mystery Hunt 2017 Cutting the Cord
MIT Mystery Hunt 2022 Lists of Large Integers

phonetic alphabet

These puzzles use the NATO phonetic alphabet (alpha, bravo, ...) or another similar standard code where a word is used to clearly communicate each letter through an audio channel. For the International Phonetic Alphabet used for phonetic transcription of speech, see IPA (international phonetic alphabet)

Pig Latin

MIT Mystery Hunt 1998 Final Runaround
MIT Mystery Hunt 2000 The Duck Konundrum
MIT Mystery Hunt 2014 WAT?
MIT Mystery Hunt 2015 Eh?
MIT Mystery Hunt 2020 Pirate Ship
MIT Mystery Hunt 2020 Pig
MIT Mystery Hunt 2021 Analog Circuitry
MIT Mystery Hunt 2021 Attack of the Lobsters
MIT Mystery Hunt 2022 Drive-Thru Dilemma

pigpen cipher

MIT Mystery Hunt 2005 Dirty Laundry
MIT Mystery Hunt 2008 Safari Park
MIT Mystery Hunt 2013 Open Secrets
MIT Mystery Hunt 2014 Guess What I'm Thinking
MIT Mystery Hunt 2018 Vain Snowball
MIT Mystery Hunt 2019 Running for Office
MIT Mystery Hunt 2020 Pig
MIT Mystery Hunt 2021 Paint
MIT Mystery Hunt 2021 Squee Squee
MIT Mystery Hunt 2021 For Your Eyes Only
MIT Mystery Hunt 2022 Lessons Learned from Porcine Construction
MIT Mystery Hunt 2023 Graffiti
MIT Mystery Hunt 2024 Subplutonean IHTFP Blues

Playfair square cipher

MIT Mystery Hunt 1997 Languedoc Culture Attributes Modern Civilization to Elvis!
MIT Mystery Hunt 2012 Behave
MIT Mystery Hunt 2018 Building Challenge
MIT Mystery Hunt 2019 Have You Seen Me?
MIT Mystery Hunt 2021 Athletics
MIT Mystery Hunt 2022 Altered Transmissions
MIT Mystery Hunt 2023 Too Many Secrets
MIT Mystery Hunt 2024 A Trip Down Memory Lane

playing cards code (assigning letters to specific cards)

MIT Mystery Hunt 2003 Whoa-I Know Prestidigitation
MIT Mystery Hunt 2004 Cards
MIT Mystery Hunt 2005 Dogs Playing Poker
MIT Mystery Hunt 2006 Gross Solitaire

PLU codes

MIT Mystery Hunt 1999 Warrant 4.3 (Vegetable Surprise)
MIT Mystery Hunt 2009 The Apples in Stereo
MIT Mystery Hunt 2023 Apples Plus Bananas

police alphabet

See phonetic alphabet

produce PLU codes

MIT Mystery Hunt 1999 Warrant 4.3 (Vegetable Surprise)
MIT Mystery Hunt 2009 The Apples in Stereo

QR code

MIT Mystery Hunt 2010 Queasy Reaction
MIT Mystery Hunt 2011 N-tris
MIT Mystery Hunt 2012 Snap Judgment
MIT Mystery Hunt 2013 ...fixes the wavy zigzag jumble
MIT Mystery Hunt 2014 Black and White
MIT Mystery Hunt 2016 Honey, I Shrunk the Hunt!
MIT Mystery Hunt 2018 Sports Radio
MIT Mystery Hunt 2018 Bark Ode
MIT Mystery Hunt 2021 Bingo
MIT Mystery Hunt 2022 How To Do Quality Reviews
MIT Mystery Hunt 2024 Scan

qwerty

See keyboard

rail fence cipher

The rail fence cipher, also called zigzag cipher, is a particular transposition cipher where a message is encoded by writing it in a zigzag pattern across the page, then reading the letters row by row.

MIT Mystery Hunt 2013 Security Theater
MIT Mystery Hunt 2024 Deep Conspiracy

resistor color code

MIT Mystery Hunt 2002 Resistance is Fuchsia
MIT Mystery Hunt 2005 Paint Store
MIT Mystery Hunt 2011 Da Vinci's Workshop Meta
MIT Mystery Hunt 2012 March Madness
MIT Mystery Hunt 2013 Megamix
MIT Mystery Hunt 2014 I Came Across a Japanese Rose Garden
MIT Mystery Hunt 2018 Starship Enterprise
MIT Mystery Hunt 2019 Ridin' Delhi
MIT Mystery Hunt 2021 A Bit of Light
MIT Mystery Hunt 2023 Restoration
MIT Mystery Hunt 2024 Inaugural Funky Stickperson Contest

ring sizes

MIT Mystery Hunt 2019 Tree Ring Circus

ROT-13

MIT Mystery Hunt 2006 Spoiler Warning!
MIT Mystery Hunt 2012 Keeping Records
MIT Mystery Hunt 2018 Texts from Mom
MIT Mystery Hunt 2021 Analog Circuitry

RSA cipher

MIT Mystery Hunt 2004 Noise in the Air
MIT Mystery Hunt 2006 Ask Ye Silly Question...

runes

See Futhorc

scytale

The scytale is a cipher where a narrow ribbon is wrapped around some cylindrical object and a message is written across the windings of the ribbon rather than along it. The right size cylinder (or a lot of patience) is required to decipher it.

MIT Mystery Hunt 1996 9B
MIT Mystery Hunt 2003 First Round Puzzle
MIT Mystery Hunt 2018 Mass Aid

semaphore

shifting letters

(like Caesar ciphers or Vigenere, but with separate shifts provided for every letter)

shortlex order

MIT Mystery Hunt 2012 Any Old Puzzle

Sign Language

MIT Mystery Hunt 2004 Quagmire
MIT Mystery Hunt 2006 Louder than Words
MIT Mystery Hunt 2008 Manual Transmission
MIT Mystery Hunt 2022 Projection Booth
MIT Mystery Hunt 2024 The Venetian

Smithy code

MIT Mystery Hunt 2007 Round V Meta

Solitaire (encryption algorithm from Cryptonomicon)

MIT Mystery Hunt 2017 Patience for the Bridge Builder
MIT Mystery Hunt 2018 Marked Deck

steganography

MIT Mystery Hunt 1998 8.137 Physics and Information Theory of the Vacuum
MIT Mystery Hunt 2004 Reminder's World
MIT Mystery Hunt 2006 Long Division
MIT Mystery Hunt 2010 Words Get in the Way
MIT Mystery Hunt 2011 The Crypt
MIT Mystery Hunt 2015 Read Between the Lines
MIT Mystery Hunt 2019 Picture Book
MIT Mystery Hunt 2019 The Bill
MIT Mystery Hunt 2020 best song ev-er!
MIT Mystery Hunt 2022 Red Herring
MIT Mystery Hunt 2023 Lost to Time

T9

See phonespell (2 = A,B,C)

tap code

Tap code is an unencrypted 5x5 cipher, typically with C & K combined, rather than I & J or U & V, as is common in other such ciphers.

MIT Mystery Hunt 2013 Magic: The Tappening
MIT Mystery Hunt 2022 Drive-Thru Dilemma
MIT Mystery Hunt 2024 This Space Intentionally Left... Well, You Know

telephone exchange words (like 55 = Klondike)

(see also phonespell)

MIT Mystery Hunt 2004 Fair Trade
MIT Mystery Hunt 2012 Phantom of the Operator Meta

ternary cipher

transposition cipher

This is any kind of cipher where the identities of the letters remain intact, but they are arranged into a different order. There are many names for specific variations of this cipher, but a typical case is for a text to be split into a number of equal rows, then read down the columns.

MIT Mystery Hunt 1994 25
MIT Mystery Hunt 1996 The Impossible Tribar
MIT Mystery Hunt 1996 Escher Meta
MIT Mystery Hunt 2013 Security Theater
MIT Mystery Hunt 2017 Great Tits!

Unicode

MIT Mystery Hunt 2003 Standard Excuses
MIT Mystery Hunt 2010 Words Get in the Way
MIT Mystery Hunt 2011 Squared Key
MIT Mystery Hunt 2012 Encoded
MIT Mystery Hunt 2012 Watson 2.0 Meta
MIT Mystery Hunt 2013 This Page Intentionally Left Blank
MIT Mystery Hunt 2013 I CAN'T SPELL YOU
MIT Mystery Hunt 2015 Takeout Ordering
MIT Mystery Hunt 2016 Unimaginably Twisted Files
MIT Mystery Hunt 2017 Dispatches from the Foreign Service Units
MIT Mystery Hunt 2021 Le Chiffre Indéchiffrable

UPC barcodes

MIT Mystery Hunt 1999 Stuttgart
MIT Mystery Hunt 2005 Bars of Soap
MIT Mystery Hunt 2008 Checkout Lines
MIT Mystery Hunt 2013 Numbers

Vigenère cipher

ZIP codes

MIT Mystery Hunt 1996 9C
MIT Mystery Hunt 2000 Art for Art's Sake
MIT Mystery Hunt 2004 Xipe-Dee-Doo-Dah
MIT Mystery Hunt 2004 Fair Trade
MIT Mystery Hunt 2005 Junk Mail
MIT Mystery Hunt 2006 Boston Ante
MIT Mystery Hunt 2010 Bulls and Cows
MIT Mystery Hunt 2017 A Lengthy Journey
MIT Mystery Hunt 2020 Zip Line
MIT Mystery Hunt 2022 The Hound of the Vast-Cur-Villes

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