National Security Agency

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This article is about the US government agency. For other uses, see NSA (disambiguation).
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NSA seal

The National Security Agency / Central Security Service (NSA/CSS) is a United States government agency responsible for both the collection and analysis of message communications, and for the security of government communications against similar agencies elsewhere. It is a part of the Department of Defense. Its eavesdropping brief includes radio broadcasting, both from organizations and individuals, the Internet, and other intercepted forms of communication, especially confidential communications. Its secure communications brief includes military, diplomatic, and all other sensitive, confidential or secret government communications. Despite having been described as the world's largest single employer of Ph.D. mathematicians, the owner of the single largest group of supercomputers, and having a budget much larger than that of the CIA, it has had a remarkably low profile until recent years. For a long time its existence was not even admitted by the US government. It has even been referred to as "No Such Agency."

Because of its listening brief, the NSA/CSS has been heavily involved in cryptanalytic research, continuing the work of its predecessor agencies which had been responsible for breaking many World War II codes and cyphers (see, for instance, Purple code, Venona, and JN-25).

Headquarters for the National Security Agency is at Fort George G. Meade, Maryland, approximately ten miles (16 km) northeast of Washington, DC. NSA has its own exit off of the Baltimore-Washington Parkway, labeled "NSA Employees Only". The scale of the operations at the NSA is hard to determine from unclassified data, but one clue is the electricity usage of NSA's headquarters. NSA's budget for electricity exceeds US$21 million per year, making it the second largest electricity consumer in the entire state of Maryland. Photos have shown there are about 18,000 parking spaces at the site, although most guesses have put the NSA's workforce at around double that number; employees are sited worldwide.

Its secure government communications brief has involved NSA in production of communications hardware and software, in the production of semiconductors (there is a chip fabrication plant at Ft. Meade), in cryptography research, and contracting with private industry for items, equipment, and research it is not itself prepared to develop or supply. Again, this continues responsibilities inherited from its predecessors (see SIGABA).


Agency history

The origins of the National Security Agency can be traced to an organization originally established within the Department of Defense, under the command of the Joint Chiefs of Staff as the Armed Forces Security Agency (AFSA), on May 20, 1949. The AFSA was to be responsible for directing the communications and electronic intelligence activities of the military intelligence units - the Army Security Agency, Naval Security Group and the Air Force Security Service. However, the agency had little power and lacked a centralized coordination mechanism. The creation of NSA resulted from a December 10, 1951, memo sent by Walter Bedell Smith to James B. Lay, Executive Secretary of the National Security Council. The memo observed that "control over, and coordination of, the collection and processing of Communications Intelligence had proved ineffective" and recommended a survey of communications intelligence activities. The proposal was approved on December 13, 1951, and the study authorized on December 28, 1951. The report was completed by June 13, 1952. Generally known as the "Brownell Committee Report," after committee chairman Herbert Brownell, it surveyed the history of U.S. communications intelligence activities and suggested the need for a much greater degree of coordination and direction at the national level. As the change in the security agency's name indicated, the role of the NSA was extended beyond the armed forces.

NSA was created in June 1952 by Executive Order of President of the United States Harry S. Truman [1] ( Truman's Executive Order was itself classified and remained unknown to the public for more than a generation.

Involvement with non-government cryptography

NSA has been involved in debates about public policy, both as a behind-the-scenes advisor to other departments, and directly during and after Vice Admiral Bobby Ray Inman's directorship.

The NSA was embroiled in controversy concerning its involvement in the creation of the Data Encryption Standard (DES), a standard and public block cipher used by the US government. During development by IBM in the 1970s, the NSA recommended changes to the algorithm. There was suspicion the agency had deliberately weakened the algorithm sufficiently to enable it to eavesdrop if required. The suspicions were that a critical component — the so-called S-boxes — had been altered to insert a "backdoor"; and that the key length had been reduced, making it easier for the NSA to discover the key using massive computing power.

However, the public reinvention of the technique known as differential cryptanalysis suggested that one of the changes (to the S-boxes) had actually been suggested to harden the algorithm against this -- then publicly unknown -- method of attack; differential cryptanalysis remained publicly unknown until it was independently reinvented and published some decades later. The shortening of the 128-bit key used by the IBM submission to a nominal 64, but actually an effective 56, bits is believed to have been a deliberate weakening of the algorithm, making possible an exhaustive search for the key by those with sufficient computer power and funding.

Possibly because of previous controversy, the involvement of NSA in the selection of a successor to DES, the Advanced Encryption Standard (AES) was limited to hardware performance testing (see AES competition).

NSA was a major player in the debates of the mid to late 1990s regarding US munitions export regulations. Cryptographic software and hardware had long been classed with fighter planes, tanks, cannons, and atomic bombs as controllable munitions.

The NSA/CSS has, at times, attempted to restrict the publication of academic research into cryptography; for example, the Khufu and Khafre block ciphers.


Main article: ECHELON

NSA headquarters in Fort Meade, Maryland
NSA headquarters in Fort Meade, Maryland

NSA/CSS, in combination with the equivalent agencies in the United Kingdom (Government Communications Headquarters), Canada (Communications Security Establishment), Australia (Defence Signals Directorate), and New Zealand (Government Communications Security Bureau), and otherwise known as the UKUSA group, is believed to be responsible for, among other things, the operation of the ECHELON system. Its capabilities are suspected to include the ability to monitor a large proportion of the world's transmitted civilian telephone, fax and data traffic. The system has as one of its most important bases the nominally RAF-run station at Menwith Hill (54.0162 N; 1.6826 W) near Harrogate, Yorkshire. Technically, almost all modern telephone, internet, fax & satellite communications are exploitable due to recent advances in technology and the 'open air' nature of a lot of radio communications around the world.

Many people oppose NSA's presumed collection operations, assuming that the NSA/CSS infringes on Americans' privacy by spying on the United States' own citizens. However, the NSA's USSID 18 (United States Signals Intelligence Directive) strictly prohibits the interception or collection of ANY information about "..US persons, entities, corporations or organizations..." without explicit written legal permission from the Attorney General of the United States. The Supreme Court has ruled that intelligence agencies cannot conduct surveillance against American citizens. There are of course a few extreme circumstances where collecting on a US entity would be allowed without a USSID 18 waiver, such as with civilian distress signals, or sudden emergencies (such as 9/11, however the USA PATRIOT Act has significantly changed privacy legality.)

It has been suggested that in practice, NSA/CSS implements an end run around legal restrictions on internal surveillance by having partner agencies spy on the citizens of other partner's countries, thereby avoiding illegal spying on their own citizens.

In the past, there have been alleged instances of improper violations of USSID 18 that occurred in violation of the NSA's strict charter prohibiting such acts. In addition, ECHELON is considered with indignation by citizens of countries outside the UKUSA alliance, with widespread suspicion that the United States government uses it for motives other than its national security, including political and industrial espionage. The chartered purpose of the NSA/CSS is solely to acquire significant foreign intelligence information pretaining to National Security or ongoing military intelligence operations.



(USA, USAF, and USN are the United States Army, United States Air Force, and United States Navy, respectively.)

Deputy Directors

Notable Cryptanalysts

NSA encryption systems

Main article: NSA encryption systems

NSA is responsible for the encryption-related components in these systems:

  • EKMS Electronic Key Management System
  • FNBDT secure narrow band voice standard
  • Fortezza encryption based on portable crypto token in PC Card format
  • KL-7 ADONIS off-line rotor encryption machine (post-WW II to 1980s)
  • KW-26 ROMULUS electronic in-line teletype encryptor (1960s–1980s)
  • KW-37 JASON fleet broadcast encryptor (1960s–1990s)
  • KY-57 VINSON tactical radio voice encryptor
  • SINCGARS tactical radio with cryptographically controlled frequency hopping
  • STE secure telephone
  • STU-III older secure telephone

Past and present SIGINT activities

See also

Further reading

External links

de:National Security Agency fr:National Security Agency ja:アメリカ国家安全保障局 nl:NSA no:National Security Agency pl:National Security Agency sv:National Security Agency


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