Digital information privacy system

Abstract

A system for determining a maximum length digital sequence is constructed by selecting a Mersenne Prime integer and a primitive polynomial having an ORDER equal to the Mersenne Prime integer. An arbitrarily selected mask m is either provided to the transmitter and receiver, or constructed, at either, or both. The mask is used to create a decimated M sequence, and work backwards to define a recursion rule vector r which is associated with another primitive polynomial corresponding to the decimated M sequence. This recursion rule vector r is used to create a new feedback shift register which produces a maximum length sequence. An initialization vector i is provided to the transmitter and receiver and used as an initial load of the shift register. A selected stage of this register is exclusive-ORed ('XORed') with each bit of a plaintext message to be sent to result in cipher text. At the receiver, the same process is performed with the same mask m, and initialization vector i, to create the same recursion rule vector r, and shift register. The same stage of this shift register is then XORed with the received ciphertext message to result in the original plaintext message.