The publication of secret information by WikiLeaks and multiple media outlets, followed by news coverage of leaks involving high-profile national security operations, has heightened interest in the legal framework that governs security classification and declassification, access to classified information, agency procedures for preventing and responding to unauthorized disclosures, and penalties for improper disclosure. Classification authority generally rests with the executive branch, although Congress has enacted legislation regarding the protection of certain sensitive information. While the Supreme Court has stated that the President has inherent constitutional authority to control access to sensitive information relating to the national defense or to foreign affairs, no court has found that Congress is without authority to legislate in this area. This report provides an overview of the relationship between executive and legislative authority over national security information, and summarizes the current laws that form the legal framework protecting classified information, including current executive orders and some agency regulations pertaining to the handling of unauthorized disclosures of classified information by government officers and employees. The report also summarizes criminal laws that pertain specifically to the unauthorized disclosure of classified information, as well as civil and administrative penalties. Finally, the report describes some recent developments in executive branch security policies and legislation currently before Congress (S. 3454).