Classified information is material that a government or group of governments claims is sensitive information that requires secrecy based on national or regional security needs. Access is restricted by law or regulation to particular groups of people and mishandling can incur criminal penalties. A formal security clearance is often required to handle classified documents or access classified data. The clearance process usually requires a satisfactory background investigation. There are typically several hierarchical levels of sensitivity (e.g. restricted, confidential, secret and top secret), with differing clearance requirements