Self Synchronizing Digital Scramblers

A known way of scrambling binary data for security purposes is by adding to it, bit by bit, a pseudorandom sequence A. Synchronization is established by providing the descrambler with the states of A's generator. It is shown here how for data transmitted in blocks, the states of the generator can be recovered at any instant which enables self-synchronization. If the block length is
k
and the generator of A consists of an
n
-stage register, there is a delay of
k(n - 1) + 1
bits, between sync lost and sync recovery.