National security letter

A national security letter is a letter that can be sent by the government to a company or organization. The government sends this letter if they think they need information for national security reasons.

Think of it like when you ask your mom for something, but instead of asking nicely, the government sends a letter saying "I need this information right now for important reasons."

The company that receives the letter usually has to give the government the information they are asking for, even if they don't want to. They also can't tell anyone that they received the letter, so it's a secret.

This is because the government thinks that if people knew they were asking for information, they wouldn't be able to keep the country safe from harm.

Overall, a national security letter is a way for the government to get information they need quickly, but it's also a big secret that nobody can talk about.