President's Daily Brief (PDB)
An intelligence and analysis report the President receives each day from the Director of National Intelligence.
For more, read the New York Times story.
SCIF
A building (or part of a building) designated for working with secure compartmented information.
SCIFs are protected from electronic and other surveillance, Access to one is extremely restricted and controlled.
Security Clearance
A security clearance (or just clearance) is a certification by the government that a person is allowed access to information considered potentially damaging to national security.
Potential damage can take many forms, such as...
o Exposing the identity of an undercover agent
o Revealing operational plans
For more, see this State Department fact sheet.
Security Clearance Level
Sensitive government information is classified according to the amount of damage exposure might cause. A person must have a security clearance of at least that classification in order to be allowed to access it.
There are 3 main levels of security clearances...
Secret: Access to information that could cause serious harm to national interests if revealed.
Top-Secret: The most restrictive clearance - with access to information that could cause grave damage. Access to Top-Secret information is further restricted to only those with a "need to know". This information may be further classified as Special Access Program or Secure Compartmented Information(SCI). The use of secure compartment information is almost always restricted to a Secure Compartmented Information Facility (SCIF).