The National Security Agency (NSA) is an organization of the United States that works specifically to protect information sent from the US, and to decode information that may be sent out by other countries. Usually such information is encrypted, and to this purpose the National Security Agency has many employees specializing in decoding material, also called crypto analysis. The organization has become much better known in the mid 2000s for its expanded role in domestic surveillance of things like telephone calls, what some refer to as “domestic spying.” This has led to serious debate on the degree to which the NSA should be empowered to evaluate the communications of private citizens who may have only “suspected” but unproven associations with terrorist organizations.

Unlike other security agencies of the US, the NSA is limited by charter to the analysis of communications in other countries. Since the attacks on September 11, 2001, more power has been given to the National Security Agency to carry out domestic surveillance. This was not the initial intent of the agency.

The organization was formed in 1952, when previously, various agencies of the military employed crypto analysis to evaluate signals and communications of other countries. Yet many felt that an overhead organization was needed so that data collected could be better coordinated. A review of the collection and organization efforts of several military intelligence units, called the Brownell Committee Report, recommended such an organization in 1951, resulting in the creation of the National Security Agency the following year.

There are several functions of the National Security Agency. It analyzes various communications via phone, radio, television, and Internet, collects information and organizes it, and reports to and shares information with the Department of Defense, which is its overhead agency. A branch of the NSA called the Signals Intelligence Directorate (SID) carries out this work. It plays a vital role in the US intelligence community in this respect.

The other aspect of the NSA that has become increasingly important in a computer age is researching and studying how information in the US, especially classified information, is held and disseminated. The National Computer Security Center, a branch of the National Security Agency, may work with private companies too, to help them develop the best information systems to protect the privacy of their customers and communications. All work dedicated to the protection of US information is conducted under the second main branch of the National Security Agency, called the Information Assurance Directorate (IAD).

Not all work conducted by the National Security Agency is known because the agency as part of military operations is able to maintain high levels of secrecy. Even the specific number of employees and the extent of the operation are kept closely guarded. The main building which houses much of the operations of the NSA is located in Maryland, and the organization is always overseen by a high ranking officer of the military, usually a lieutenant general or vice admiral. The name of the person who heads the NSA is not private information, and there have been numerous directors, made by presidential appointment. Deputy directors tend to be civilians with significant experience in the field of information collection and protection.