National Security Agency

National Security Agency

National Security Agency (NSA), an independent agency within the U.S. Dept. of Defense. Founded by presidential order in 1952, its primary function is to encode and decode communications intelligence and to protect U.S. signals and information systems. The mission of its Information Systems Security department (INFOSEC) is to protect classified and sensitive information stored on government computers or networks. The NSA includes the Central Security Service, established in 1972 to promote a full partnership between the NSA and the cryptological elements of the armed forces, and the National Cryptologic School. The agency, which is headquartered in Fort Meade, Md., is the largest employer of mathematicians in the country. Its director must be a military officer. For many years the NSA was the most hidden of U.S. intelligence agencies; its large budget was secret and its existence barely acknowledged.

See J. Bamford, The Puzzle Palace (1982) and Body of Secrets (2001).

The National Security Agency/Central Security Service (NSA/CSS) is a cryptologic intelligence agency of the United States government, administered as part of the United States Department of Defense. Created on November 4, 1952, it is responsible for the collection and analysis of foreign communications and foreign signals intelligence, which involves a significant amount of cryptanalysis. It is also responsible for protecting U.S. government communications and information systems from similar agencies elsewhere, which involves a significant amount of cryptography. The NSA has recently been directed to help monitor U.S. federal agency computer networks to protect them against attacks.

The NSA is directed by a lieutenant general or vice admiral. The NSA is a key component of the U.S. Intelligence Community, which is headed by the Director of National Intelligence. The Central Security Service is a co-located agency created to coordinate intelligence activities and co-operation between the NSA and U.S. military cryptanalysis agencies. Contrary to popular impression, the NSA's work is limited to communications intelligence and not field or human intelligence activities. By law the NSA's intelligence gathering is limited to foreign communications, but its work includes some domestic surveillance.


The National Security Agency is divided into two major missions: the Signals Intelligence Directorate (SID), responsible for the production of foreign signals intelligence information, and the Information Assurance Directorate (IAD), responsible for the protection of U.S. information systems.


The NSA's eavesdropping mission includes radio broadcasting, both from various organizations and individuals, the Internet, telephone calls, and other intercepted forms of communication. Its secure communications mission includes military, diplomatic, and all other sensitive, confidential or secret government communications. Despite having been described as the world's largest single employer of mathematicians, and the owner of the single largest group of supercomputers, it has tried to keep a low profile. For many years its existence was not even acknowledged by the U.S. government.

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

In 2004, the NSA Central Security Service and the National Cyber Security Division of the Department of Homeland Security (DHS) agreed to expand the NSA Centers of Academic Excellence in Information Assurance Education Program.

As part of National Security Presidential Directive 54/Homeland Security Presidential Directive 23 (NSPD 54), signed on January 8, 2008 by President Bush, the NSA became the lead agency to monitor and protect all of the federal government's computer networks from cyber-terrorism.


Headquarters for the National Security Agency are at Fort George G. Meade, Maryland, approximately ten miles (16 km) northeast of Washington, D.C. NSA has its own exit off the Baltimore-Washington Parkway labeled "NSA Employees Only". The scale of the operations at the NSA is hard to determine from unclassified data; photos have shown there to be 18,000 parking spaces at the site. In 2006, the Baltimore Sun reported that the NSA was at risk of electrical overload because of insufficient internal electrical infrastructure at Fort Meade to support the amount of equipment being installed. This problem was apparently recognized in the 1990s but not made a priority, and "now the agency's ability to keep its operations going is threatened". Its secure government communications work has involved NSA in numerous technology areas, including the design of specialized communications hardware and software, production of dedicated semiconductors (at the Ft. Meade chip fabrication plant), and advanced cryptography research. The agency contracts with the private sector in the fields of research and equipment.

In addition to its Ft. Meade headquarters, the NSA has other facilities such as the Texas Cryptology Center in San Antonio, Texas.


The origins of the National Security Agency can be traced to the May 20, 1949 creation of the Armed Forces Security Agency (AFSA). This organization was originally established within the U.S. Department of Defense under the command of the Joint Chiefs of Staff. The AFSA was to be responsible for directing the communications and electronic intelligence activities of the US military intelligence units—the Army Security Agency, the Naval Security Group, and the Air Force Security Service; however, the agency had little power and lacked a centralized coordination mechanism. The creation of the NSA resulted from a December 10, 1951, memo sent by CIA Director Walter Bedell Smith to James S. 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.

The creation of the NSA was authorized in a letter written by President Harry S. Truman in June of 1952. The agency was formally established through a revision of National Security Council Intelligence Directive (NSCID) 9 on October 24, 1952, and officially came into existence on November 4, 1952. President Truman's letter was itself classified and remained unknown to the public for more than a generation.


The heraldic insignia of NSA consists of a bald eagle facing its right, grasping a key in its talons, representing NSA's clutch on security as well as the mission to protect and gain access to secrets. The eagle is set on a background of blue and its breast features a blue shield supported by thirteen bands of red and white. The surrounding white circular border features "National Security Agency" around the top and "United States of America" underneath, with two five-pointed silver stars between the two phrases. The current NSA insignia has been in use since 1965, when then-Director, LTG Marshall S. Carter (USA) ordered the creation of a device to represent the Agency.

Effect on non-governmental cryptography

NSA has been involved in debates about public policy, both as a behind-the-scenes adviser to other departments, and directly during and after Vice Admiral Bobby Ray Inman's directorship. NSA was a major player in the debates of the 1990s regarding the export of cryptography. Restrictions on export were reduced but not eliminated in 1996.

Data Encryption Standard (DES)

The NSA was embroiled in some controversy concerning its involvement in the creation of the Data Encryption Standard (DES), a standard and public block cipher algorithm used by the US government and banking community. During the development of DES by IBM in the 1970s, the NSA recommended changes to some details of the design. There was suspicion that these changes had weakened the algorithm sufficiently to enable the agency to eavesdrop if required, including speculation that a critical component—the so-called S-boxes—had been altered to insert a "backdoor" and that the reduction in key length might have made it feasible for NSA to discover DES keys using massive computing power. It has since been observed that the S-boxes in DES are particularly resilient against differential cryptanalysis, a technique which was not publicly discovered until the late 1980s, but which was known to the IBM DES team. The United States Senate Select Committee on Intelligence reviewed NSA's involvement, and concluded that while the agency had provided some assistance, it had not tampered with the design.

Clipper chip

Because of concerns that widespread use of strong cryptography would hamper government use of wiretaps, the NSA proposed the concept of key escrow in 1993 and introduced the Clipper chip that would offer stronger protection than DES but would allow access to encrypted data by authorized law enforcement officials. The proposal was strongly opposed and key escrow requirements ultimately went nowhere. However, NSA's Fortezza hardware-based encryption cards, created for the Clipper project, are still used within government, and the NSA ultimately published the design of the SKIPJACK cipher (but not the key exchange protocol) used on the cards.

Advanced Encryption Standard (AES)

Possibly because of previous controversy, the involvement of NSA in the selection of a successor to DES, the Advanced Encryption Standard (AES), was initially limited to hardware performance testing (see AES competition). NSA has subsequently certified AES for protection of classified information (for at most two levels, e.g. SECRET information in an unclassified environment) when used in NSA-approved systems. The widely-used SHA hash functions were designed by NSA.

Dual EC DRBG random number generator

The NSA promoted the inclusion of a random number generator called Dual EC DRBG in the U.S. National Institute of Standards and Technology's 2007 guidelines that has again attracted speculation about the presence of a backdoor which would allow NSA access to data encrypted by systems using that random number generator.

Academic research

The NSA has invested many millions of dollars in academic research under grant code prefix MDA904, resulting in over 3,000 papers (as of 2007-10-11). NSA funding sources are often declared in the papers, but some researchers try to conceal or otherwise play down the source

The NSA/CSS has, at times, attempted to restrict the publication of academic research into cryptography; for example, the Khufu and Khafre block ciphers were voluntarily withheld in response to an NSA request to do so.


The NSA has the ability to file for a patent from the US Patent and Trademark Office under gag order. Unlike normal patents, these are not revealed to the public and do not expire. However, if the Patent Office receives an application for an identical patent from a third party, they will reveal the NSA's patent and officially grant it to the NSA for the full term on that date.

One of the NSA's published patents describes a method of geographically locating an individual computer site in an Internet-like network, based on the latency of multiple network connections.

NSA programs


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), otherwise known as the UKUSA group, is widely reported to be in command of the operation of the so-called 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, according to a December 16, 2005 article in the New York Times.

Technically, almost all modern telephone, internet, fax and satellite communications are exploitable due to recent advances in technology and the 'open air' nature of much of the radio communications around the world. The NSA's presumed collection operations have generated much criticism, possibly stemming from the assumption that the NSA/CSS represents an infringement of Americans' privacy. However, the NSA's United States Signals Intelligence Directive 18 (USSID 18) strictly prohibits the interception or collection of information about "...U.S. persons, entities, corporations or organizations..." without explicit written legal permission from the United States Attorney General, when the subject is located abroad, or the Foreign Intelligence Surveillance Court when within U.S. Borders. The U.S. Supreme Court has ruled that intelligence agencies cannot conduct surveillance against American citizens. There are a few extreme circumstances where collecting on a U.S. entity is allowed without a USSID 18 waiver, such as with civilian distress signals, or sudden emergencies such as the September 11, 2001 attacks; however, the USA PATRIOT Act has significantly changed privacy legality.

There have been alleged 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 numerous allegations that the United States government uses it for motives other than its national security, including political and industrial espionage. Examples include the gear-less wind turbine technology designed by the German firm Enercon and the speech technology developed by the Belgian firm Lernout & Hauspie. An article in the Baltimore Sun reported in 1995 that aerospace company Airbus lost a $6 billion contract with Saudi Arabia in 1994 after the NSA reported that Airbus officials had been bribing Saudi officials to secure the contract. The chartered purpose of the NSA/CSS is solely to acquire significant foreign intelligence information pertaining to National Security or ongoing military intelligence operations.

In his book Firewall, Andy McNab speculates that the UKUSA agreement is designed to enable the NSA, GCHQ, and other equivalent organizations to gather intelligence on each other's citizens. For example, the NSA cannot legally conduct surveillance on American citizens, but GCHQ might do it for them.

Domestic activity

The NSA's mission, as set forth in Executive Order 12333, is to collect information that constitutes "foreign intelligence or counterintelligence" while not "acquiring information concerning the domestic activities of United States persons". The NSA has declared that it relies on the FBI to collect information on foreign intelligence activities within the borders of the USA, while confining its own activities within the USA to the embassies and missions of foreign nations.

The NSA's domestic surveillance activities are limited by the requirements imposed by the Fourth Amendment to the U.S. Constitution; however, these protections do not apply to non-U.S. persons located outside of U.S. borders, so the NSA's foreign surveillance efforts are subject to far fewer limitations under U.S. law. The specific requirements for domestic surveillance operations are contained in the Foreign Intelligence Surveillance Act of 1978 (FISA), which does not extend protection to non-U.S. citizens located outside of U.S. territory.

These activities, especially the publicly acknowledged domestic telephone tapping and call database programs, have prompted questions about the extent of the NSA's activities and concerns about threats to privacy and the rule of law.

Wiretapping programs

Domestic wiretapping under Richard Nixon
In the years after President Richard Nixon resigned, there were several investigations of suspected misuse of Central Intelligence Agency (CIA) and NSA facilities. Senator Frank Church headed a Senate investigating committee (the Church Committee) which uncovered previously unknown activity, such as a CIA plot (ordered by President John F. Kennedy) to assassinate Fidel Castro. The investigation also uncovered the NSA's wiretaps on targeted American citizens. After the Church Committee hearings, the Foreign Intelligence Surveillance Act of 1978 became law, limiting circumstances under which domestic surveillance was allowed.
ThinThread wiretapping and data mining
A wiretapping program named ThinThread was tested in the late 1990s, but never put into operation. ThinThread contained both advanced data mining capabilities and built-in privacy protections. These privacy protections were abandoned in the post-9/11 effort by President George W. Bush to improve the intelligence community's responsiveness to terrorism. The research done under this program may have contributed to the technology used in later systems.
Warrantless wiretaps under George W. Bush

On December 16, 2005, the New York Times reported that, under White House pressure and with an executive order from President George W. Bush, the National Security Agency, in an attempt to thwart terrorism, had been tapping the telephones of individuals in the U.S. calling persons outside the country, without obtaining warrants from the United States Foreign Intelligence Surveillance Court, a secret court created for that purpose under the Foreign Intelligence Surveillance Act (FISA).

Proponents of the surveillance program claim that the President has executive authority to order such action, arguing that laws such as FISA are overridden by the President's Constitutional powers. In addition, some argued that FISA was implicitly overridden by a subsequent statute, the Authorization for Use of Military Force, although the Supreme Court's ruling in Hamdan v. Rumsfeld deprecates this view. In the August 2006 case ACLU v. NSA, U.S. District Court Judge Anna Diggs Taylor concluded that the NSA's warantless surveillance program was both illegal and unconstitutional. On July 6, 2007 the 6th Circuit Court of Appeals overturned Judge Taylor's ruling, reversing her findings.

AT&T Internet monitoring
In May 2006, Mark Klein, a former AT&T employee, alleged that his company had cooperated with the NSA in installing hardware to monitor network communications including traffic between American citizens.

Transaction data mining

The NSA is reported to use its computing capability to analyze "transactional" data that it regularly acquires from other government agencies, which gather it under their own jurisdictional authorities. As part of this effort, the NSA now monitors huge volumes of records of domestic emails and Internet searches as well as bank transfers, credit-card transactions and travel and telephone records, according to current and former intelligence officials interviewed by the WSJ.

In fiction

Since its known existence, the NSA has become more widely known in the last few decades, and particularly since the 1990s, the agency has regularly been portrayed in spy fiction. Many such portrayals grossly exaggerate the organization's involvement in the more sensational activities of intelligence agencies. An indication of the agency's increased fame is its central role in the films Sneakers and Enemy of the State. The NSA has been featured in many other films, television shows, books, roleplaying games, and video games.



Deputy Directors

Notable cryptanalysts

NSA encryption systems

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

  • EKMS Electronic Key Management System
  • FNBDT Future Narrow Band Digital Terminal
  • 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
  • KG-84 Dedicated Data Encryption/Decryption
  • SINCGARS tactical radio with cryptographically controlled frequency hopping
  • STE secure telephone equipment
  • STU-III secure telephone unit, currently being phased out by the STE
  • TACLANE product line by General Dynamics

NSA has specified Suite A and Suite B cryptographic algorithms to be used in US government systems; the Suite B algorithms are a subset of those previously specified by NIST and are expected to serve for most information protection purposes, while the Suite A algorithms are secret and are intended for especially high levels of protection.

Some past NSA SIGINT activities

See also

NSA computers


Further reading

External links

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