History Main / TwoKeyedLock

* In ''Machinima/FreemansMind'', Gordon accidentally launches what he believes to be a missile (it's actually a satellite delivery rocket, but he hadn't been paying attention to the security guard who told him about it) and afterward mentions that he would have expected one of these instead of just the BigRedButton he pressed. Even for a satellite delivery rocket, and even considering he was resuming an aborted launch, yeah, you'd think the procedure would be at least a little more complex.

* ''Film/Terminator2JudgmentDay'' had a two-keyed lock to access the vault where the arm and chip were kept.

* ''Film/Godzilla2014''. A nuclear weapon on the deck of a naval vessel is armed via this trope, which along with the [[EverythingsBetterWithSpinning spinning cogs]] and countdown clock is presumably for RuleOfDrama rather than realism.

* ''Literature/{{Deathlands}}''. In "Ice and Fire", three keys are required to open the cover over a BigRedButton. As the places where the keys were kept are likely nuked out of existence, a tiny charge of [=C4=] does the job instead.

** ''VideoGame/TheLegendOfZeldaFourSwords''-series has a lot of puzzles which include the "four buttons, each of them only triggers if a person is standing on it"-factor. In some of the games this is subverted by "one player controls four characters". At some places this is required to move on, at others it's just "drop a lot of loot"!
** In fact, there are a lot of these in the Zelda games. Sometimes using a block or the assistance of lovely Princess Zelda (as a Phantom) to push one, or hitting a series of switches with the boomerang. ''[[VideoGame/TheLegendOfZeldaMajorasMask Majora's Mask]]'' has plenty of these in the Stone Tower, and in order to work them you need the Elegy of Emptiness, which creates a statue duplicate of your form, and the Zora and Goron masks.

* ''VideoGame/ChipsChallenge'': A unique version appears in the 121st level, ''Perfect Match''. There's a meandering corridor from whence cloned fireballs are moving to die in a moat of water. Right in front of the clone machine is a toggle door that opens and closes when the level's green buttons are being pressed. Ideally, the door should be closed so the corridor clears up and Chip can reach the exit, but in the central area of the level there are two paths where fireballs move, and each path happens to have a green button as well (and they're pressed whenever Chip or a mook steps onto them). The trope comes into play when Chip makes it so those two buttons are pressed at the same time, canceling out the toggle command and leaving the clone machine's door in its current state (open or closed); this is easier said than done, because it requires pushing a block to kill any surplus fireballs in one of the routes (the other cannot be manipulated), and any mistake will require im to clone new fireballs in that route to recalibrate. Chip can then press a green button in his area in case the toggle door remains open (after the fireballs' pressing match is done) in order to close it, allowing him to finally reach the exit.

* The movie ''Film/CrimsonTide''. Two keys needed to unlock the missile launch controls. The XO refuses the Captain's orders to unlock the controls because they lost communications before the launch order was confirmed as protocol demands. Mutiny ensues.
** One might notice that this is EXACTLY WHY there ARE two keys.
** The Captain was in fact acting on legitimate launch orders and the XO was refusing those orders due to the possibility they had received orders to cancel the launch. The real villains of the film were the (unseen) President and Secretary of Defense, who issued nuclear launch orders with the intention of rescinding them if the situation changed. There are no take-backs in thermonuclear warfare.
** Aside from the Captain and XO having their own arming keys, the Captain's safe has additional keys that needed to be passed out to other crewmembers during launch preparations. The missile launching switch itself was also located in the Missile Control Compartment, behind a multi-door safe; only the weapons officer (played by Viggo Mortensen) had the combinations to the locks.

* Film/JamesBond

** ''Film/NoTimeToDie''. SPECTRE raids a secret [=MI6=] laboratory and demands access to one of the biovaults, which requires two scientists. The moment the two are identified, the others are shot dead, then when the weapon they are after has been removed [[YouHaveOutlivedYourUsefulness one of the scientists is killed]] and the [[CantKillYouStillNeedYou other taken with them]].

** That destruct sequence is taken verbatim from the infamously {{anvilicious}} TOS episode, "Let That Be Your Last Battlefield". [[ThePasswordIsAlwaysSwordfish Twenty years later, they still hadn't changed the codes,]] to the point where Chekov has to declare himself "acting Science Officer" rather than his normal position as chief of Security.
** In TNG, it's often the Captain and Executive Officer, so the "two senior officers" may be in lieu of the XO in the event that they are unavailable. The ''Enterprise''-E was slated to self-destruct on confirmation from Worf and Crusher since Riker was unavailable at the time.

** The entire launch process required two men before even getting to the point in which they turned the keys. A nuclear launch would begin with the transmission of a 35-character code message, such as "Golf-Hotel-6-2-7-Alpha-etc." The commander and his deputy would then write the code in a notebook and compare what they had written once the message had concluded. Having agreed that they had both written the message correctly, they thus had a "valid message" and could open the locked red safe. Both officers had their own combination for a lock on the safe, so they needed to agree to open it. The commander would check the first two characters and find an authenticator envelope with those two. If the plastic "cookie card" inside the envelope matched the last five characters of the message, then it was not a drill and they had permission to insert their launch keys. Hidden inside the message was the ordered launch time and also the unlock code for the missile, which then opened one of the four fuel/oxidizer inlet valves, kept locked to prevent an unintentional or unauthorized launch, and begin loading the missile with the fuel needed to reach its target. Once the keys were turned and the "launch enabled" light came on, the missile was entirely independent and would accept no further orders from the crew. There was no reset button anywhere. Only 58 seconds after turning the keys, the missile would launch and be on its way.

* In some poor villages of Africa where they have opted for Food Bank (filled with food aid for use when the harvest is lean and topped up by local farmers when the harvest is good) three people from the community are given keys and required to open it. Because as Josette Sheeran says; [[http://www.ted.com/talks/josette_sheeran_ending_hunger_now.html food is gold]]

* The Film/JamesBond film ''Film/GoldenEye'' had this for the titular weapon as well, defeated by simply having two villains working together. [[spoiler:Interestingly, this was replicated in the secret underground base as well.]]

** Apparently, the final PowerLimiter placed upon [[PersonOfMassDestruction Hayate Yagami]] in ''Anime/MagicalGirlLyricalNanohaStrikers'' had to be removed simultaneously by [[TheBrigadier Admiral Chrono Harlaown]] and [[GoodShepherd Knight Carim]], making it one even though they didn't have to be physically present near Hayate at the time.

* The nuclear missile locks in ''Film/TheHuntForRedOctober'' apparently had one of these. Although we never see the locks themselves, we see Captain Ramius taking possession of both keys -- which, as the doctor points out, sort of defeats the point. The movie plays with the idea that Ramius has gone mad and intends to start WW3, but in [[Literature/TheHuntForRedOctober the novel]] this idea is rejected as five officers are needed to carry out a launch. It also stated that in the event of the political officer's death, the captain was ''supposed'' to take charge of his key. There were probably other standing orders as to who inherits the other keys in the event of any of the other officers with launch keys dying on a voyage as well. A two key (two combination in the book) system was also used on a safe in the submarine that contained the mission orders and code books. Moreover, while the movie version plays up that Captain Ramius took both launch keys as if he could single-handedly activate the missiles, the locks are intentionally positioned far apart enough in the room that it is ''physically impossible'' for one man to turn both keys simultaneously.

* Apparently, German libraries have a long tradition of keeping locked rooms known as the "giftschrank" (literally "poison cabinet") which contained censored writings considered to be hazardous (heretical writings in the past, Nazi literature more recently). In some libraries, the doors have dual locks with keys held by two separate staff members to ensure that only authorized people can access the works.

* Unfortunately frequent in the [=PS2=]-exclusive ''VideoGame/HalfLife1'' expansion ''Decay'', where the designers' idea of co-operative gameplay was to include puzzles that require two players to work synchronously to be solved efficiently, such as turning switches on opposing sides of a room simultaneously.

** Similarly the Fork Tower in ''VideoGame/FinalFantasyV''. The tower will explode if both rewards aren't taken simultaneously, so [[LetsSplitUpGang you're forced to split the party]].

* On ''WesternAnimation/TheSimpsons'' two keys were required to be turned simultaneously to drop the "perfect 300 game" balloon at the bowling alley.

** In [[Recap/TheSimpsonsS12E9HOMR "HOMЯ"]], When Homer goes to the bank to withdraw his family's life savings, he's informed that the money cannot be withdrawn unless both he and Marge agree to it. He goes to the other side of a nearby plant to pretend he's talking Marge into agreeing and then he forges her signature. He also pretends Bart is there asking for a bonbon.

** One can actually see this decay in the franchise. In the days of the original series, voice-print match and codes from three senior officers are necessary to activate the auto-destruct sequence. In the days of TNG and DS9, it only takes two with biometric hand scans, and requires both to disable it. By the time of Voyager, Janeway could apparently destroy the entire ship on a whim.

** One can actually see this decay in the franchise. In the days of the original series, voice-print match and codes from three senior officers are necessary to activate the auto-destruct sequence. In the Next-Gen days, it only only takes two with biometric hand scans, and requires both to disable it. By the time of Voyager, Janeway could apparently destroy the entire ship on a whim.