The National Security Agency is now infamous, perhaps, for its global signals intelligence mission. But the agency, since its inception, has had many other important national security functions under its very large umbrella. Here are six:

1. The NSA generates and distributes all nuclear weapon unlock and launch codes. In a secure, hardened, and largely underground tank of sorts near Finksberg, Maryland, workers at the NSA's "Key Support Central Facility" preside over an automated process that produces and packages physical keys, transmits encryption algorithms for systems that can be coded "over the air," and keeps a log of all communication security violations. Yes, it has a website. There is a back-up classified key support facility in the western United States.

2. The NSA provides information assurance, or IT security, to all Defense Department and the intelligence community, and generates encryption keys and secure communication channels for the entire U.S. government. The NSA engineers the connection that allows STE phones, now the standard for "Red" or classified voice communications, to encrypt telephone calls over regular phone lines, if necessary.

3. The NSA works to break the encryption keys used by foreign governments.

4. The NSA's Defense Special Missile and Astronautical Center fuses communications intelligence, electronic intelligence, foreign signature and instruments intelligence and radar intelligence to detect and analyze missile launches anywhere in the world. It is the primary focal point for all ballistic missile defense system coordination, working directly with NORAD and other monitoring entities.

5. The NSA conducts cyberwar. As historian Matthew Aid noted in Foreign Policy, the NSA's Tailored Access Operations division is charged with hacking into computer networks, systems and servers worldwide. The TAO's Access Technologies Operations Branch works with the CIA's classified Technology Management Office to physically break into places. (What does the U.S Cyber Command, which is co-located with NSA, do? It develops policies and plans and keeps permission slips locked in a box somewhere. When a task is identified, the requesting party goes to CYBERCOM, which then tasks TAO with the order, basically giving them a permission slip.) TAO's work force includes members from all military branches, civilians, and contractors.

6. The NSA works with the Defense Advance Research Projects Agency (DARPA) and private industry to research, manufacture and test elements for use in quantum computers, perhaps the most significant national security advance that can be predicted.