Open Secret

""Brilliant!" Harry whispered. "If everyone knows, no one will suspect it's a secret!""

- Harry Potter, Harry Potter and The Methods of Rationality

This trope is when a particular piece of information is officially declared to be secret... but it is widely known by everyone anyway. The characters might as well not even attempt The Masquerade, because all the civilians around them know who they are and what they are up to. And that super-secret bit of gossip that no one can ever know? Hate to tell you this, but everyone knows it already. Of course, the holders of the secret continue to act as if no one outside of their little group knows anything at all.

Overt Operative is a Sub Trope. Contrast to The Not Secret, where the creators pretend the "secret" is actually secret right up until The Reveal.

Anime & Manga

 * In To Love Ru, the fact that Lala is an alien is treated like this for quite a while, as everyone either already knows, or doesn't care when they find out.
 * In Naruto a law exists that forbids anyone revealing that the titular character is the vessel of the Nine-Tailed Fox. While this means that Naruto's generation and those younger are ignorant of the Nine-Tails, every person able to remember the attack knows about it.
 * The secret becomes even more open in Shippuden where several members of Naruto's generation openly discuss the matter.
 * As of the  it is officially not a secret anymore..
 * In Mobile Suit Zeta Gundam, Quattro's real identity as Char. Not only would the audience not be fooled (the same character design, the visible scar, the same voice actor) but the fact that he flies around in a custom red Rick Dias shows that he isn't exactly keeping a low profile.

Comic Books

 * In his own book, Wolverine, Patch was actively concealing the fact that he was, in fact, the titular superhero while he was operating in "deep cover" in Madripoor. Of course, all of his contacts knew he was Wolverine, though they chose not to reveal this. They figured it was best not to delve too deeply into the private affairs of a walking blender.
 * When the Human Torch of the Fantastic Four, a character whom the in-universe public knows as Johnny Storm, got his own ongoing feature in Strange Tales starting in issue #101, he maintained a secret identity in his home town of Glenville -- the inhabitants of which knew his sister Sue was the Invisible Girl, but obtensibly don't know who the Torch was (the four schoolmates who do know who he is are now out-of-town graduates who were sworn to secrecy). #106 had him discover that everyone knew who he really is after all, they just respected his privacy.
 * In Brian Michael Bendis' 2001 Daredevil run, Matt Murdock's Secret Identity was outed. Although the accusation was "officially" fought back, since then everyone knows or at least heavily suspects Matt Murdock is Daredevil, so much so that he had to cease practicing law himself for a time due to the fodder it supplied the opposing counsel.

Fanfiction

 * In the Glee fanfic We have a problem, Kurt and Puck go to great lengths to keep their relationship a secret. When they finally decide to come out, it turns out that more or less everybody already knew.

Film

 * James Bond's status as a 00 Agent is supposed to be classified. Pretty much everyone on Earth with any sort of connection to a government, a terrorist organization, or an intelligence agency knows about him, though.
 * In Good Night and Good Luck there is a subplot dedicated to Joseph Wersha and his wife as they try to keep their marriage secret or risk getting fired. Naturally at the end of the movie it is revealed that every one in the office already knew they were married and just didn't care. But they still have to leave because of budget cuts and are asked to walk, which they agree to.
 * In Johnny Dangerously, the fact that nightclub owner Johnny Kelly is secretly the titular mob boss is known to everyone in the world other than Johnny's mother and little brother. This is pointed out to Johnny by the Pope.
 * The sequel "Dark Lord: The Rise of Darth Vader reveals that Padme's pregnancy was this in Revenge of the Sith''. Only C3-PO doesn't know what it means when a woman's belly takes this shape. Note that she uses large senatorial dresses to hide it, but smart senators probably noticed she constantly wore this!

Literature
It's mentioned that even King Verence knows about the still and maintains the secret, having long ago learnt that the way to avoid the embarassment of witches refusing to pay taxes (or in this case, excise) is never to ask them.
 * At the end of Harry Potter and The Philosopher's Stone, Dumbledore knows that this trope is in full force when he says "what happened in the dungeons between [Harry] and Professor Quirrell is a complete secret -- so, naturally, the whole school knows."
 * In Gerald Morris in The Ballad of Sir Dinadan. Tristram and Isolde have the world's least secret love affair--literally everyone but Isolde's husband knows, and he at least suspects. This is mostly because Tristram has been riding about the country telling everyone in great detail about the vow of silence he has taken and how he can never even say his true love Isolde's name.
 * The trope also applies to Lancelot and Guinevere's affair in the first couple of books, though in this case it's treated more seriously due to the effect it has on Arthur and the court.
 * In Discworld, everybody knows Carrot is the true king of Ankh-Morpork, but nobody speaks openly about it. The last guy who tried
 * The short story "The Sea and Little Fishes" has the townspeople of Lancre going through ridiculous contortions to find Nanny Ogg. They know where she is; she's at her secret still in the woods. But actually aknowledging this would be unthinkable, so they wander around near where they all know the still is, calling her name. When she finally comes to see what all the fuss is about, they say they thought she might be in the woods picking herbs.
 * Pillars Of The Earth makes occasional mention of priests who are officially celibate, yet have a "live-in housekeeper", a polite fiction maintained for the benefit of all concerned; the protagonist for the first half of the book is married to one such housekeeper's mysteriously fatherless daughter. Literally everyone knows what's actually going on, with senior Church officials pretending to be taken in because actually enforcing the celibacy rule would be more trouble than it's worth. This is probably Truth in Television.

Live Action TV
"Rupesh: You're Torchwood?
 * On Torchwood, the eponymous organization is supposed to be a top-secret organisation beyond the reach of the British government (though answerable to the Queen). Pretty much everyone in Cardiff seems to know who they are and what they do and they liaise with Whitehall on occasion. Heck, they print the name of their "secret" organization on their vans.

Jack Harkness: (while climbing into the Conspicuous Black SUV with "TORCHWOOD" written all over it) Never heard of 'em."


 * This is only made worse by the fact that the team regularly orders pizza under the name Torchwood and has it delivered to the front door of their headquarters. Also, Torchwood's allegedly clandestine dealings with the supernatural are the worst-kept secret in the UK. The show makes hay out of how loudly everything about them screams The Men in Black, especially with some very loud alien encounters in the Whoniverse.

"Gwen: Excuse me. Have you seen a blowfish driving a sports car? [old woman points the way] Thank you.
 * And of course:

Old Woman: Bloody Torchwood."

"Buffy: Was there a school bulletin? Was it in the newspaper? Is there anyone in this town who doesn't know I'm the Slayer?"
 * Some people believe that The Masquerade in Buffy the Vampire Slayer was broken early on, if not before the show started. This is made much more clear in the Third Season episode "The Prom", during which Buffy is given the "Class Protector" award.
 * In the very first episode:


 * Get Smart: Many times when Max would ask the operator to patch him through to a 'number which she must immediately forget', she responds with, "Oh, you mean CONTROL!"
 * On NCIS, Jimmy Palmer and Michelle Lee's Secret Relationship turns out to be this, as Team Gibbs already knew about it when Palmer confessed.

Professional Wrestling

 * Until fairly recently when he officially came out, everybody knew Pat Patterson was gay, but aside from the occasional incredibly veiled reference, it was something that just wasn't discussed.
 * When Jerry Lawler's son Grandmaster Sexay wrestled in WWE, Lawler didn't want it to be mentioned on air, as he thought it made him look old. So Jim Ross kept making jokes about who his father might be.
 * Triple H and Stephanie McMahon were a on-screen couple until they "divorced" in early 2002. They then got married for real in 2003, which resulted in various references, like Triple H telling Vince McMahon that they're "practically family", until it was flat out stated during the buildup to Wrestlemania XXV.
 * The fakeness of wrestling was not officially acknowledged for many years, but upon the death of Owen Hart, Jim Ross admitted it usually was fake, but that Owen's injuries were real. Ross didn't get fired because he handled the situation so well otherwise.

Video Games
"Phoenix Wright: (If it's so secret, why is it the most prominent thing in the exihibit?)"
 * Lampshaded by the title character of Phoenix Wright Ace Attorney: Trials and Tribulations during the Kurain Village exihibit in regards to the Six Leaf Kurain Sacred Writings folding screen, "the greatest of all the spirit channeling secrets".

Webcomics

 * Towards the end of Bob and George, George's secret identity in the hand-drawn continuity is shown to be one of these.
 * In El Goonish Shive this happens when suddenly Elliot becomes ill and his previously unheard of cousin Ellen is temporarily transferred instead. Yeah, sure.
 * A Magical Roommate: The country of Umbria considers the existence of our world to be a highly classified secret. This is news to everybody, including the dragon who published books on our world and placed them in a public library.
 * The Dreamer: Beatrice and Alan Warren's relationship is supposedly a secret, but his cousin Ebenezer says "...it's private to all of Roxbury and half of Boston!"
 * Guenevere's relationship with Lancelot in Arthur King of Time and Space is a bit like this. Obviously Arthur (and the rest of the court) can't officially know, because that would be a scandal. So they work very hard not to officially know, despite attempts to force the issue.

Western Animation

 * The Venture Brothers: The Sovereign is the leader of the guild, and his identity is a well kept secret...except almost everyone knows he's David Bowie. Yes David Bowie
 * The My Little Pony Friendship Is Magic episode "Green Isn't Your Color" had Spike confess his deepest secret to Twilight and Pinkie...his crush on Rarity. A secret everyone in town was already aware of...except for Pinkie of course.
 * A House of Mouse episode had Clarabelle about to reveal a big secret and everybody in the Club is worried is going to be his/her secret. By asking Clarabelle what about, they finish revealing their own secret to Clarabelle instead: Mickey do something in his ears so are always rounded no matter angle you see it, while Donald reveal he's part Goose. When is Goofy turn, he discard Mickey's and Donald's like everybody already know that, but his secret, according to him, is bigger

Real Life

 * Israel's nukes. They haven't officially revealed them yet, but when then-Prime Minister Ehud Olmert accidentally (or perhaps accidentally on purpose) said that Israel had nukes in a speech in 2006, the world barely noticed.
 * Of course, there isn't much reason to keep a nuclear arsenal secret--the main point of having it is intimidating the other side not to attack, something a secret doomsday device isn't so good at.
 * The reason for Israel going this route is strategic. Israel's potential regional enemies (e.g. Iran, Iraq, Egypt ) know it has nukes, and are thus deterred from military action that would threaten Israel's existence. They can't acquire their own nukes because they're parties to the Nuclear Non-Proliferation Treaty (NPT), which forbids owning any (except for the US, Soviet Union/Russia, China, the UK and France) and subjects them to IAEA inspections. And they can't withdraw from the NPT without an "imminent threat" to their security (such as a nearby rival having nukes already), which officially doesn't exist because Israel officially refuses to confirm anything. In other words, it's an endless cycle of I Know You Know I Know and Willful Blindness on both sides. (Not fear of IAEA inspections, as many Israelis claim; Israel is not a party to the NPT and unlikely to become one in the foreseeable future, so it's not subject to inspections, and declaring its stockpile would have no effect on that-- any Israel politician mentioning inspections is just trying to scare you.)
 * Everybody pretty much knows that the United States (particularly the CIA) is responsible for the "mysterious" drone missile attacks in both Pakistan and Afghanistan, since they're the only country with the motive and means to do so. However, so far, American officials have never officially admitted any responsibility or association with the attacks.
 * The military installation located on the southern shore of Groom Lake in Nevada, also known as Area 51, has gone through most of its life being barely acknowledged (if at all) by the government, even when it's open knowledge that many advanced aircraft had been developed and tested there over the decades, including the first American jet fighter, the P-59 Airacomet. The secrecy around the base has of course fueled much debate about just what goes on there.

The base's existence was still considered a secret until it was sued over deaths from improper disposal of toxic waste, at which point the jig was basically up.
 * Though that lawsuit was thrown out by executive order to prevent any details about Groom Lake appearing in court.
 * Rule #1 of /b/: Do not talk about /b/. Rule #2 of /b/: Do NOT talk about /b/. To that end, expect almost any mention of /b/ anywhere on the Internet to be replied to with "Rules 1 and 2!!!!" even though pretty much everyone knows about /b/ by now. Expect that to get the response "That only applies to raids," but those, too, are likely to get leaked to Encyclopedia Dramatica within 24 hours.
 * The recent Wikileaks release of US diplomatic cables falls into this category for much of the information: everyone knows people in the diplomatic service badmouth other governments they deal with because, well, people. It's just not diplomatic to say so.
 * One of the amusing effects of an Open Secret, such as that of the existence of Groom Lake, is that if information is classified, people covered by security laws or similar confidentiality rules, are not allowed to talk about it until it's specifically declassified, even if everyone else already knows about the information.
 * At one point, the Bush Administration attempting to reclassify information that had already been released to the public.
 * In-N-Out Burger's "secret menu", especially "Animal Style" burgers and fries. They even acknowledge it on their website, though The Other Wiki has a more complete list.
 * The DiefenBunker - a massive underground complex a short ways outside Ottawa, sold to the country as a transmitting station, but actually intended for continuing government operations in the event of a nuclear strike on the Canadian government. In true Canadian fashion, it remained secret for roughly six minutes, as a suspicious reporter got in a plane and took pictures of the significant number of toilets being stocked there, ready to be taken underground. Far more toilets than would ever be needed for a simple transmission centre.
 * The Kelvedon Hatch Secret Nuclear Bunker certainly counts. It also gets bonus points for its helpful tourist signs.
 * When Catherine the Great of Russia ruled, it was a not-secret that she had a bastard son named Alexei by one of her lovers. Given that she treated him like a son and all but said it several times one could argue that she didn't even consider it a secret, but it wasn't until her son took the throne and acknowledged Alexei as his half-brother that it became official.
 * The NSA. For a long time the US government denied its existence, to the point where the standard joke was that NSA stood for No Such Agency. Now, they've got a web site.
 * The sexuality of many gay celebrities in the days before such things were "allowed" - Liberace, Paul Lynde, and Rock Hudson, to name a few.