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FBI
Federal Bureau of Investigation, a U.S. government law enforcement agency. 

Firewall
A collection of components or a system that is placed between two networks and possesses the following properties: 1) all traffic from inside to outside, and vice-versus, must pass through it; 2) only authorized traffic, as defined by the local security policy, is allowed to pass through it; 3) the system itself is immune to penetration.

Firmware
Equipment or devices within which computer programming instructions necessary to the performance of the device's discrete functions are electrically embedded in such a manner that they cannot be electrically altered during normal device operations.

Function
A mathematical relationship between two values called the input and the output, such that for each input there is precisely one output.