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Today's xkcd:


For the background, check out some of the 42,400 Google Scholar hits for alice bob and charlie, or the 65,000 hits for alice bob eve, or the 31,100 hits for alice bob dave


  1. Francois Lang said,

    October 31, 2022 @ 8:48 am

    Reminds me of Bob & Carol & Ted & Alice…



  2. Ben Zimmer said,

    October 31, 2022 @ 11:46 am

    Wikipedia says Alice and Bob were first used in the context of cryptography in: Rivest, Ron L.; Shamir, Adi; Adleman, Len (February 1, 1978) "A Method for Obtaining Digital Signatures and Public-key Cryptosystems," Communications of the ACM 21 (2): 120–126. "For our scenarios we suppose that A and B (also known as Alice and Bob) are two users of a public-key cryptosystem" (p. 121).

    Carol/Carlos/Charlie and Dan/Dave/David came later for generic third and fourth participants, and Eve (for an eavesdropper) was evidently introduced in: Bennett, Charles H.; Brassard, Gilles; Robert, Jean-Marc (1988) "Privacy Amplification by Public Discussion," SIAM Journal on Computing 17 (2): 210–229. (See the Cryptocouple site for further history.)

    The site "explain xkcd" notes this isn't the first time Randall Munroe has had fun with Alice and Bob (et al.): see xkcd #177 and #1323.

  3. Brett said,

    October 31, 2022 @ 2:47 pm

    (This was Friday's comic actually.)

    There is a subtle but potentially interesting language-related aspect of this xkcd comic, related to (of all peculiar things) the female character's hair. When Randall depicts real people in his comics (such as Richard Stallman, Gretchen McCulloch, or even the never-explicitly-identified Felisa Wolfe-Simon), he usually depicts them with some approximation of their actual hairstyles (including facial hair for men). For most other female characters, he uses a standard one of his stock stick figure designs, which feature several different possible hairstyles. However, in this comic, Alice is drawn with shoulder-length curly hair—which is not one of Randall's regular stock types.

    Normally, one would expect him to use his default female figure, which resembles the one in the comic, except with straight hair. The issue that Randall apparently encountered is that that character (although she does not represent the same person from one comic to another—unlike, say, Black Hat Guy) nonetheless has a name: Megan. So it appears that the woman in this comic had to be drawn with a somewhat different hairstyle because she is not named Megan, but rather Alice.

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