National Security Agency
The National Security Agency/Central Security Service (NSA/CSS) is a collaborative sector of the United States defense agencies, created in 1952. It presides over the creation and breaking of codes in accordance with the increasing necessity for cryptology in the armed forces and foreign affairs, as well as managing the communication and information systems of the United States. It provides services to the US Department of Defense, the Intelligence Community, government agencies, industry partners, select allies and coalition partners, and war planners and fighters. The NSA has two main missions: the Information Assurance mission prevents foreign adversaries from gaining access to classified information. The second being the Signals Intelligence mission which observes, collects, and analyzes intelligence data from foreign signals for intelligence and counterintelligence purposes and supports various military operations. The NSA also is entrusted with the Network Warfare operations to combat terrorist organizations at home and abroad, in keeping with U.S. laws and the protection of privacy and civil liberties. Keith B. Alexander is the Director of NSA and Chief of CSS. John C. Inglis is the Deputy Director of the NSA.
The history of the agency can be traced back to July 1917, during the creation of the United States Cipher Bureau of Military Intelligence during WWI. The Bureau was established for the purposes of code breaking following the British interception of the Zimmerman Telegram, which aimed to incite war between Mexico and the United States.
In 1919, the Cipher Bureau relocated to New York City and shifted its objectives towards Diplomatic intelligence. In 1922, surveillance of Japanese telegrams helped American diplomats negotiate naval arms limitations in the Washington Naval Conference.
During WWII, intelligence gathered by the bureau helped American fighter planes intercept and shoot down the plane of Japanese Admiral Yamamoto.
Following the conclusion of WWII, President Truman reorganized American signals intelligence into the National Security Agency in 1952. By 1969, the NSA grew to employ over 90,000 individuals making it world's largest intelligence organization. The agency played a key role in major Cold War events such as the Cuban Missile Crisis and the building of the Berlin Wall.
following the September 11th attacks, the NSA shifted its' role into data mining and domestic security. President George W. Bush authorized the NSA to monitor the phone calls and emails of American citizens without the need for a court warrant, in a bill known as the Freedom Act..
While the wiretap program was ended in 2007, later revelations made in 2013 by Edward Snowden revealed that the agency had be covertly gathering communications metadata from millions of Americans and foreign diplomats.
NSA in Popular Media
On March 7, 2017, WikiLeaks released 8,761 documents regarding the NSA. "Year Zero" is regarded as the first of other security leaks. In the time of the leak, it was regarded the largest release of confidential documents in agency history.  WikiLeaks official release statement explains the content, "'Year Zero' introduces the scope and direction of the CIA's global covert hacking program, its malware arsenal and dozens of 'zero day' weaponized exploits against a wide range of U.S. and European company products, include Apple's iPhone, Google's Android and Microsoft's Windows and even Samsung TVs, which are turned into covert microphones." Upon release, major discussions sparked around the White House's power and scope of cyber security. Documents also revealed close cooperation with British Intelligence agency, M15.
One notable finding released in the documents explains funding and acquisition of employees under a newly constructed CIA branch, the Center for Cyber Intelligence, or CCI. This branch mimics powers of the NSA, but with less oversight and public attention. Additional findings include Government hacking of Apple products, Android products, smart TVs, routers, a U.S. Consulate being used as a CIA base in Frankfurt, and the lack of control in cyber weapons.
In popular political-thriller, Scandal, character Jake Ballard, eventually becomes the director of the NSA. In the show, Ballard was previously part of a covert department of the CIA, nicknamed B6-13, where they are trained to kill prominent foreign leaders and make it look like a suicide or accident. Jake is shown as a morally-ambiguous person, often killing people with little to no remorse or sadness. Due to his time as B6-13, Jake's mindset is to similar to that of another B6-13 character, Huck. They are shown to have impulses to kill and are addicted to brutally torturing their victims. Jake initially was introduced as spying on Olivia Pope, showing his strong penchant for surveillance.
Technology and Research
The NSA is the largest employer of mathematicians in the United States who are tasked with breaking codes, as well as conducting research on signals intelligence. Their research claims to defend national security. Part of conducting research is to ethically disclose information, however research conducted on breaking code and computer exploits at NSA is not disclosed, raising questions about their mission and conducting actual ethical work. Much of the communication technology released in the past few decades is sophisticated and many are unlikely able to understand how it works as well as their implications. As cutting edge research is conducted at the NSA, newly discovered exploits target civilian resources who may be unaware of these circumstances. The NSA is involved in several fields of research, including but not limited to communications hardware, semiconductor research, and cryptography.
The NSA's involvement with covert spying throughout the Cold War and in the modern War on Terror has put the agency at the forefront of ethical issues concerning privacy and fourth amendment rights.
In the 1970s U.S. intelligence agencies including the NSA fell under public scrutiny in aftermath of the Watergate Hotel Scandal. An investigation conducted by the U.S. Senate Church committee revealed that the NSA had been spying on all telegrams entering and leaving the country dating back since 1945.  The agency had also been spying on the communications of civil rights leaders and protesters of the Vietnam War. Despite the 1978 passing of the Foreign Intelligence Surveillance Act (FISA), which required the agency to obtain warrants from a special court, later revelations revealed that the agency had covertly constructed a large and complex domestic spying program.
Since 2001, the NSA has cooperated with the US government in illegal surveillance of domestic communications and communication records. In 2013, NSA contractor Edward Snowden partnered with Guardian Journalist Glenn Greenwald to publish what would be the first of many revelations on the agency's massive domestic spying program. In June, 2013 information was leaked to media outlets that American telecom provided Verizon had been cooperation with the NSA to hand over subscriber information in compliance with a secret court order. It was soon revealed that nearly every other telephone company in the country was also cooperating with the NSA.
Ties with AT&T
It is known that major telecommunications carriers like AT&T also cooperate in handing over the requested documents and tapping customer telecommunications. The fact was first revealed in news in December 2005, then in May 2006, the USA Today wrote a story on the statements of several Congress members, who revealed that the NSA is also receiving copies of millions of civilian telecommunications records. All the activities are in violation of the privacy regulations established by Congress and the US Constitution.
AT&T is also fully involved with the organization, as it also installed a fiberoptic splitter at its facility at 611 Folsom Street in San Francisco, copying all emails, web browsing, and other forms of telecommunications to and from AT&T customers, providing the copies to the NSA.
In the next set of revelations released by Edward Snowden included information of the agency's PRISM program. PRISM allowed the NSA to directly access the servers of major technology company's such as Google, Facebook, Microsoft, Apple and many others.
Further revelations revealed that the NSA was spying on numerous foreign leaders and governments including German Chancellor Angela Merkel.
In 2013, Edward Snowden, an NSA computer analyst, leaked classified government documents revealing the NSA's surveillance activity on not only individuals they saw as threats to national security but individuals in general, including prominent leaders of other countries. The leaks revealed the agency's XKeyscore tool, which allowed the NSA to search for nearly everything a user communicates through the internet. Additionally, the agency has also collected vast sums of cellphone and email metadata. While the agency states that it doesn't collect the content of calls or email communication, an article by the Verge states that if the British Empire had access to such information gathering tools in 1775, it would be likely that American revolutionary Paul Revere famous night ride would have been predicted and intercepted.
The indiscriminate and warrant-less collection of data has been a concern for privacy advocates throughout both the United States and the world. U.S. Congress Woman Zoe Lofgren has stated that the program is a direct violation of Fourth Amendment Rights. Though the NSA's stance on the program has been that individuals with nothing to hide should be unconcerned with the program, vast amounts of metadata collected means that anyone with three degrees of relations to suspected terrorists can be targeted by the dragnet. 
In addition, it was revealed that the agency was taking active steps to circumvent internet security and device encryption. These initiatives went as far as implanting malware into the BIOS of consumer computers on the manufacturing side, ensuring that the agency had control over targeted machines.