Patent ID: 6870930

Claim:
A method for encryption of digital data for transmission from a transmitter to a receiver, comprising the steps of: a) providing digital data to a transmitter; b) performing XOR masking of the digital data with an XOR mask to produce masked digital data; c) scrambling the masked digital data using a scrambling formula to produce encrypted digital data; and d) transmitting the encrypted digital data to a receiver wherein the method further comprises the step of breaking the digital data up into at least a first portion and a second portion and wherein steps (a) to (c) are performed for the first portion and for the second portion of the digital data; wherein prior to step (b), the method further comprises the steps of i) exchanging a master key between the transmitter and the receiver, ii) deriving from the master key a first slave key for the portion of data, and a second slave key for the second portion of data; and wherein the step of deriving first and second slave keys from the master key comprises the steps of selecting M bits of the master key as initial values for M-bit LFSR; selecting a LFSR configuration based on N bits of the master key; and using the selected LFSR configuration and the M-bit LFSR to derive first and second slave keys.