NSL, also known as National Security Letter, is a term used to describe a type of subpoena or demand letter issued by U.S. government agencies, specifically the Federal Bureau of Investigation (FBI), to gather information for national security purposes. It is a tool provided under the United States Code, which grants certain government authorities the power to obtain specific customer records or other electronic communications data, without prior court approval.
An NSL typically compels recipients, such as telecommunications companies, internet service providers, financial institutions, and credit agencies, to provide requested information, which may include subscriber records, transactional data, phone numbers dialed, email addresses, and other relevant data. NSLs can also contain a non-disclosure provision that prohibits the recipient from disclosing the letter's existence or contents to the public or the individual under investigation.
NSLs have been criticized for their potential infringement on civil liberties and privacy rights, as well as their lack of judicial oversight. The non-disclosure provision has raised concerns regarding transparency and accountability of government surveillance activities. Various legal challenges have arisen, resulting in modifications to NSL statutes and increased reporting requirements.
It is important to note that the specific regulations and oversight surrounding NSLs may vary by country or jurisdiction, as this definition primarily pertains to the usage and context within the United States.
