Alice and Bob



When the interaction between two hypothetical characters is needed to explain or describe some system, they are nearly always called Alice and Bob. Alice and Bob - A and B. This duo originally started out as a standardized way to explain cryptography. Over time, the duo has been adopted in explanations of mathematics, physics, quantum effects, and other arcane places, but have also been seen in fiction. They are also found in a surprising number of trope definitions.

Where more than two characters are needed, other names are used, such as Carol and Charlie. Some names have acquired standard meanings, such as Eve the Eavesdropper. Lists of these can be found in Bruce Schneier's book Applied Cryptography, and at that other wiki.

Note that the most common names are "Alice", "Bob" and "Charlie/Charley". This works for most situations.

The use of Alice and Bob is suggested in General Suggestions, but some of us (notably those who really are called Alice and/or Bob) sometimes wish a little imagination could be applied. That's where Aerith and Bob come in. Or Jim and Mary. Or Dick and Jane.

See also Those Two Guys, Greek Chorus.

Film

 * Movie and TV example: Bob & Carol & Ted & Alice.
 * How to Lose a Guy in 10 Days has a romantic couple of Andy Anderson and Benjamin Berry.

Literature

 * In most cryptography textbooks, communications are presented as being between Alice and Bob, and must be secured from a third-party interloper named Eve (for Eavesdropper, of course!). If the problem requires the involvement of more than two parties, then Charlie and Donna may be introduced. (This is the basis for the xkcd reference listed below.) Other character names sometimes used for special purposes include Mallory (a malicious active adversary, capable of changing the messages sent between Alice and Bob, whereas Eve merely listens), Trent (a mutually trusted third party, whom Alice and Bob might prevail upon to execute protocols in which they don't trust each other), and Peggy and Victor (the prover and verifier, respectively, in zero-knowledge proofs).
 * Game Theory books often use an adaptation of Alice and Bob in "Rose and Colin" (rows and columns on game theory charts), with "Larry", or "layer" thrown in for three person games.
 * Game Semantics books tend to use Abelard and Eloise (for resemblance to the universal and existental quantifier symbols, which are an inverted A and a backwards E). They are also the names of a medieval logician and his lover.
 * Alice and Bob are the names of the parents in Vernor Vinge's Rainbows End, and a government official is named Eve Mallory.
 * E. R. Emmet's "Our Factory" puzzles feature "Alf", "Bert", "Charlie", and so on.

Live Action TV

 * TV and Movie example: Bob & Carol & Ted & Alice.
 * One of the logos at the end of The Bonnie Hunt Show (2008-2010) is for "Bob & Alice Productions".
 * Bonnie's Hunt's parents are named Bob and Alice so it is either just a reference to her parents or both.

Music Tropes

 * Nerdcore Rap artist MC Plus+ has a song about cryptography named "Alice and Bob".

Newspaper Comics

 * Dilbert does this in a one-way fashion with "Ted the Generic Guy", who has no consistent personality and shows up whenever a generic extra is needed. Bad things tend to happen to him.

Oral Tradition

 * The Story of Alice and Bob is a humorous after-dinner speech recounting their mythology.
 * A collection of Alice and Bob jokes.

Video Games

 * Used in a very surreal Cyberspace level in World of Goo called "Alice and Bob and the Third Party," where you intercept information-goo transmitted from cosmicGrrrl! to LaconicCrusadr13.
 * Used as examples for an explanation of  in Remember 11.

Web Comics

 * Parodied in this xkcd comic.
 * Alice is introduced in the opening chapter of Freak Angels. In the epilogue,

Web Original

 * Catalog Living has the imaginary Elaine and Gary.

Real Life

 * Alice and Bob really are quantum- a professor at the University of Washington has used two separate remote cameras, named Alice and Bob, to test the theory of non-locality and its potential for time travel, by attempting to receive a message before it's sent. The experiment hasn't yielded results so far, but it's telling.
 * In Linguistics, it's more often John and Mary.
 * The pattern of choosing an alphabetically-sequential string of names (Alice, Bob, Charlie...) was used for a series of alphabetical Atlantic and Pacific Railroad stations constructed across the Mojave Desert circa-1883. The first in the series is "Amboy", now a ghost town on the former US Route 66. Steam trains originally stopped at each of these sequential points to obtain water.
 * Similar alphabetically-sequential naming patterns have been used for versions of software; Ubuntu uses names of animals this way, while the Android OS used names of foodstuffs (beginning after 'B' as the base, "Cupcake", "Donut", Éclair", "Froyo", "Gingerbread", "Honeycomb", "Ice Cream Sandwich", "Jelly Bean", "KitKat", "Lollipop", "Marshmallow", "Nougat", "Oreo", "Pie", ending just before this reached 'Q').

All The Tropes

 * Amnesiac Liar
 * Arson, Murder, and Jaywalking
 * Bathroom Stall of Overheard Insults
 * Belated Happy Ending
 * Bilingual Backfire
 * Burping Contest
 * Cartoonish Companions
 * The Cat Came Back
 * Celebrity Survivor
 * Characterization Marches On
 * Class Clown
 * Coitus Uninterruptus
 * Conveniently-Common Kink
 * Curb Stomp Battle
 * Dartboard of Hate
 * Death by Adaptation
 * Debt Detester
 * Delayed Reaction
 * Derailing Love Interests
 * Description Cut
 * Did They or Didn't They?
 * Dinner Deformation
 * Don't Sneak Up On Me Like That
 * Dramatic Irony
 * Easily-Overheard Conversation
 * Explain, Explain, Oh Crap
 * Fan-Preferred Couple
 * Finish Dialogue in Unison
 * Finishing Each Other's Sentences
 * Footsie Under the Table
 * Fox News Liberal
 * From My Own Personal Garden
 * Glad I Thought of It
 * Have We Met?
 * Head-Tiltingly Kinky
 * Hilarity in Zoos
 * Holding the Floor
 * How Much Did You Hear?
 * Hurricane of Excuses
 * I Didn't Mean to Turn You On
 * Imagine Spot
 * I'm Cold... So Cold...
 * I'm Standing Right Here
 * Indulgent Fantasy Segue
 * Invisible Streaker
 * Ironic Echo
 * Jailbird of Panama
 * Just Whistle
 * Kids Shouldn't Watch Horror Films
 * Kissing in a Tree
 * Lame Excuse
 * Leaning on the Fourth Wall
 * Let Him Choose
 * Long-Distance Relationship
 * Look Behind You!
 * Mobile Shrubbery
 * More Hypnotizable Than He Thinks
 * My Favorite Shirt
 * My Name Is Not Durwood
 * My Sister Is Off-Limits
 * Never Live It Down
 * No, I Am Behind You
 * "No. Just... No" Reaction
 * Not Listening to Me, Are You?
 * Not-So-Innocent Whistle
 * One-Book Author
 * Operation: Jealousy
 * Or Are You Just Happy to See Me?
 * Patchwork Kids
 * Placebo Eureka Moment
 * Preemptive "Shut Up"
 * Premature Aggravation
 * Race For Your Love
 * Rapid Fire Interrupting
 * Rapid-Fire "No"
 * Revealing Hug
 * Right Behind Me
 * Right in Front of Me
 * Said Bookism
 * Schrödinger's Player Character
 * Selective Enforcement
 * Selling the Show
 * Separated by a Common Language
 * Sibling Switch Squick
 * Single-Target Sexuality
 * Write a Film Noir
 * Stairs Are Faster
 * Stood Up
 * Styrofoam Rocks
 * Such a Phony
 * Tag-Team Suicide
 * Taking the Heat
 * Tastes Like Chicken
 * Thanks for the Mammary
 * The Cat Came Back
 * The Exit Is That Way
 * The Matchmaker
 * The Three Trials
 * A Tragedy of Impulsiveness
 * Triang Relations
 * This Is No Time for Knitting
 * Twin Threesome Fantasy
 * Voiceover Letter
 * Walk in Chime In
 * War Ship
 * Was It Really Worth It?
 * What Is This, X?
 * Where Did We Go Wrong?
 * Who's on First?
 * Why Are You Looking At Me Like That?
 * Why Didn't You Just Say So?
 * Wounded Gazelle Gambit
 * You Know What You Did
 * You Wouldn't Believe Me If I Told You


 * Numerous Playing With pages.
 * ? and more.