Scrambler
In
telecommunication, a
scrambler is a device that transposes or inverts signals or otherwise encodes a
message at the transmitter to make the message unintelligible at a receiver not equipped with an appropriately
set descrambling device.
Note: Scramblers usually use a fixed algorithm or mechanism. However, a scrambler provides communications privacy that is inadequate for classified traffic.
Source: from Federal Standard 1037C and from MIL-STD-188