Classified Information

"Joe Quncy: The report exists? Leo McGarry: Well, I can't tell you that, Joe; it was classified. But I can tell you it was classified by the defense department."

- The West Wing, "Life On Mars"

A phrase used by characters in order to withhold certain information from others.

Compare I'd Tell You, But Then I'd Have To Kill You.

Anime and Manga
"I used to contact the future or for ... But when I hadn't heard from for a week I thought something was wrong. And then ... I was so shocked that I, but there was no ... What should I do?"
 * Suzumiya Haruhi: this is Mikuru's Catch Phrase (kinsoku jikou, in Japanese).


 * Mikuru is an interesting variant; the reason she says "classified information" is because of an information censor that was placed inside her that is always monitoring her speech to make sure she doesn't spill any futuristic time-breaking Info Dumps. She's surprised that when the restriction is lowered she can speak normally about things she couldn't say before.
 * Later referenced in Lucky Star by Patricia Martin.
 * A variation in Slayers has Xellos and his Catch Phrase "This is a secret!" (Sore wa himitsu desu!)

Fan Works

 * "That information is unavailable" is the Catch Phrase of the Human Alien Ms. Aoyama (actually a magically-disguised Nabiki Tendo) from the Ranma ½/Sailor Moon crossover fic Desperately Seeking Ranma whenever asked who she works for or how she knows something. Thanks to her ultra-Magitek A.I. assistant Jun, nothing stored electronically anywhere on the planet is inaccessible to her, making her appear nigh-omniscient -- and terrifying intelligence agencies the world over.

Literature
""It's classified information until such time as the Ministry sees fit to release it," said Percy stiffly. "Mr. Crouch was quite right not to disclose it." "Oh, shut up Weatherby," said Fred."
 * Percy's reasoning for not telling Ron, Harry and the others about the Triwizard Tournament's coming to Hogwarts in Harry Potter and The Goblet of Fire

Live-Action TV
"Officer Don: The FBI are coming into town tomorrow. Dick: What for? Officer Don: That's classified. Tommy: You have no idea, do you? [beat] Officer Don: That's also classified."
 * Spoofed on 3rd Rock from the Sun:

"Lt. Col. Mitchell: What do you mean you can't tell me? I have the highest security clearance known to mankind! What–what is 30185? Lt. Col. Carter: We were sworn to secrecy. Lt. Col. Mitchell: Well, why even mention it to me if you're not going to tell me what it is? Lt. Col.Carter: Sorry. Vala: Can you tell me? Dr. Jackson: Oh yeah, we can tell you."
 * Friends: in the episode with Charlie Sheen as Phoebe's navy boyfriend, he fields any questions about submarines with, "I really can't say." Even innocuous ones like, "Do you get to look through a periscope?"
 * Stargate SG-1 actually lampshaded their tendency for the team to be told by their CO that information was classified, despite the team having the highest possible US Government clearance.
 * This is a common misconception of Security Clearances. Just because one has a "Top Secret" security clearance doesn't mean you can read through the files of Area 51 at your leisure. You still need to demonstrate a "Need to Know". When someone talks about having "Code Word Clearance" they mean that the code-word of a particular project or operation is listed in their security file, which means they can access any information filed under that code-word. This is also was anyone talking about information being classified "Above Top-Secret" is ridiculous since you can use the same compartmentalizing system to isolate especially sensitive information.
 * And those compartmentalized systems often require an additional Sensitive Compartmented Information clearance in addition to a TS.
 * This is spoofed (along with everything else) in 200

Tabletop Games

 * +++THIS ENTRY HAS BEEN EXPUNGED BY ORDER OF THE EMPEROR'S MOST HOLY INQUISITION+++
 * We're sorry citizen. That information is above your security clearance.

Video Games

 * Primarch Victus uses this in a rare out-of-character moment to avoid having to explain the in Mass Effect 3.

Web Original
"Sarge: Classified as what? CT: Classified as something I can't tell you, now stop fishing for information! ... Grif: You can't tell us, or you won't tell us? CT: I can't tell you... which is convenient, because I don't want to tell you."
 * The SCP Foundation does this with [REDACTED] and [DATA EXPUNGED], making a situation report read like a list of Noodle Incidents.
 * Red vs. Blue: CT really doesn't want to share his information. It classified.

Western Animation
"Skipper: I'm waiting for my away team to report before declaring Defcon Red. Marlene: Uh-huh. Real quick: what's Defcon Red? Skipper: Classified. Just hope you never live to see one, sister."
 * The Penguins of Madagascar:
 * "Operation: Plush and Cover":

"King Julien: Uh, where did that cage come from? Kowalski: Sorry, that information is classified."
 * "Otter Gone Wild", after a cage is produced from Hammerspace:

"Alice: X, eh? Is that the name your mommy gave you? X: Mother never told me my real name. Said it was classified."
 * Between Agent X and Alice:

"Mittens: So you got superpowers. Does that make you some kind of superdog? Bolt: That information is classified."
 * Bolt: