The National Security Agency is the largest United States Government intelligence agency. It is responsible for the collection and analysis of foreign communications, and for the security of government communications against similar agencies elsewhere. It is a part of the Department of Defence.

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 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 in some quarters as "No Such Agency."

The agency is headquartered at Fort George G. Meade, Maryland, approximately 16 kilometres northeast of Washington, DC. It has its own exit off of the Baltimore-Washington Parkway, labelled "NSA Employees Only."

The scale of the operations at the agency is hard to determine from unclassified data, but one clue is the electricity usage of the agency's headquarters. The agency's budget for electricity exceeds US$21 million per year, making it the second largest electricity consumer in the entire state of Maryland

Its secure government communications brief has involved the agency in production of communications hardware and software, in the production of semiconductors there is a chip fabrication plant at Fort Meade, in cryptography research, and contracting with private industry for items, equipment, and research it is not itself prepared to develop or supply.

Source: China Daily