A communication device for use in a non-self synchronizing scrambling
(NS3) communication system and a method for using NS3 in a communication
system are disclosed. A digital data stream is scrambled by modifying the
digital data stream based on a pseudo-noise sequence (PNS) to produce a
scrambled digital data stream. The PNS has a timing reference that is
distinct from the digital data stream. The scrambled digital data stream
is capable of being descrambled by performing an inverse modification,
based on the same PNS and the same timing reference. The scrambled
digital data stream may be transmitted over a communication medium and
descrambled at the opposing end of the communication medium.
Synchronization between the scrambler and the descrambler is maintained
by providing a common timing reference to the scrambler and the
descrambler. The common timing reference is distinct from the data
stream. The invention can be used on any communication system in which
all the communication devices have a common timing reference.