History Main / PublicSecretMessage

** Homer sent a message to Lisa in the ''New York Times'' CrosswordPuzzle. {{Defictionalized}} by the ''NY Times'' running that same puzzle

* In ''Literature/TheAnubisGates'' by Creator/TimPowers, time travelers in the early 19th century get each other's attentions on busy city streets by whistling {{Beatles}} songs.

* In ''TrialByJournal'', Lily sends messages to the presumed dead Perry by calling him 'Hansel" ( his character in a play) in the newspaper. In return, he calls her LAW, and sends replies via the painting everyone thinks a gorilla is making. It makes sense in context.

* In ''Trial by Journal'', Lily sends messages to the presumed dead Perry by calling him 'Hansel" ( his character in a play) in the newspaper. In return, he calls her LAW, and sends replies via the painting everyone thinks a gorilla is making. It makes sense in context.

* In ''Film/MenInBlack'', Agent K explains that tabloids, which are assumed to be hoaxes by {{muggles}}, are in fact based on true events behind TheMasquerade (since tabloids have less WeirdnessCensor than "serious" newspapers). Later, when [[spoiler:agent K retires]], Agent J notices an article with [[spoiler: Agent K's photo and an article about a postal worker who returned to his old job after years in a coma.]], revealing [[spoiler: Agent K]]'s fate, which then becomes a major plot point in the second film.

* In ''Film/StarTrekIITheWrathOfKhan'', Spock tells Kirk on an open channel, "If we go by the book, hours become days". To anyone else, this might sound like a case of LawfulStupid, but Kirk, who'd been discussing regulations about coded messages with Spock earlier, knows that this means [[spoiler: to decode the next message, replace the word "days" with "hours".]]

* One of the features of "public key encryption" is that you can publish one key, letting anyone send you a message that no one without the other key can decipher. Or conversely, you can encrypt with the ''private'' key so that everyone can read your messages knowing they could only have come from you. And you can do both at the same time.

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* TheIlluminati in ''DeusEx'' use this interestingly. They communicate primarily by heavily encrypted e-mails, which they know their oppponents will pick up and read. However, the information isn't in the e-mail, it's in ''the encryption key''. Each key means "Meet me at place X, at Y o'clock, on day Z".

* A variation in IRobot with Dr. Lanning's hologram. It doesn't say much of use while in public, but the whole point was to alert Det. Spooner without anyone else noticing.

* RobertHeinlein's novel ''{{Literature/Friday}}''. In Vancouver, Friday is reading the personal ads in a newspaper and sees an ad that says "W.K.-Make your will. You have only a week to live. A.C.B." More than a week later she sees another ad in a Vicksburg, Mississippi newspaper that says "W.K.-Make your will. You have only ten days to live. A.C.B." Her traveling companion Georges realizes that the messages are a code - the first message meant "number seven" (1 week = 7 days), while the second message meant "number ten".

* A RealLife instance (several, actually): GeneRoddenberry had served in WorldWarII with a man named Kim Noonien Singh. They lost touch after the war. Roddenberry named two characters after Singh, hoping to attract his attention -- Khan Noonien Singh in the "Space Seed" episode of ''Series/StarTrekTheOriginalSeries'' (and ''Film/{{Star Trek II|The Wrath of Khan}}''); and Noonien Soongh, Data's creator in ''Series/StarTrekTheNextGeneration''.

* In ''Literature/TheAnubisGates'' by TimPowers, time travelers in the early 19th century get each other's attentions on busy city streets by whistling {{Beatles}} songs.

* In ''TheAnubisGates'' by TimPowers, time travelers in the early 19th century get each other's attentions on busy city streets by whistling {{Beatles}} songs.

* The staff at Steve Jackson Games were not allowed to release the title of one game supplement in the Power-Ups series, and the forum speculation was that they were trying to create a sudden burst of interest on release to fuel impulse buys. The author even said "I've been told that the secrecy around Power-Ups 5 does, indeed, have something to do with impulse buys." Earlier today an entire game's fanbase facepalmed at the release of '''Power-Ups 5: Impulse Buys'''.

* AgathaChristie wrote of a spy who was behind enemy lines and managed to find a really crucial piece of information but had no way of passing it on, so in the end he sacrificed himself, committing a series of murders and getting convicted - it seemed like random acts of violence but those who knew he was a spy figured that the victims' personal data was used as a code.

* A RealLife instance (several, actually): GeneRoddenberry had served in WorldWarII with a man named Kim Noonien Singh. They lost touch after the war. Roddenberry named two characters after Singh, hoping to attract his attention -- Khan Noonien Singh in the "Space Seed" episode of ''StarTrekTheOriginalSeries'' (and ''StarTrekII''); and Noonien Soongh, Data's creator in ''StarTrekTheNextGeneration''.

* In ''StarTrek II: TheWrathOfKhan'', Spock tells Kirk on an open channel, "If we go by the book, hours become days". To anyone else, this might sound like a case of LawfulStupid, but Kirk, who'd been discussing regulations about coded messages with Spock earlier, knows that this means [[spoiler: to decode the next message, replace the word "days" with "hours".]]
* In ''[[Film/{{Serenity}} Serenity]]'', the code that makes River flip out is hidden in an ad spot for Fruity Oaty Bars.

* In an episode of ''GetSmart'', The Chief (disguised as a singing waiter) communicates a message to Max and 99 by slipping code phrases into the song he is singing.

* [[http://xkcd.com/370/ This]] ''{{xkcd}}'' makes fun of the public messages in Redwall.

* During WorldWarII, the Allies would send message to friendly resistance fighters, spies and other clandestine groups behind Axis lines by making announcements over encryption civilian BBC broadcasts. While the broadcasts were open and able to be listened to by the Axis, the messages themselves would be meaningless phrases whose meaning would only be understood by the intended receiver.
** The Axis used analog computers such as the Enigma Machine, to send radio messages they believed were to heavily encoded for the allies to decipher. This provided incentive for the development of electronic computers by the Allies.

* In ''DeathNote'', Misa is a Kira-fangirl, but doesn't know who he is. So she uses her own death note to kill people and force the news to send messages. Light is annoyed, since while people who don't know about the notes won't be able to figure out what they're talking about, it is still far too public for his taste.

* During WorldWarII, the Allies would send message to friendly resistance fighters, spies and other clandestine groups behind Axis lines by making announcements over encryption civilian BBC broadcasts. While the broadcasts were open and able to be listened too by the Axis, the messages themselves would be meaningless phrases whose meaning would only be understood by the intended receiver.