It was published in Crypto 1993 by Don Coppersmith, Hugo Krawczyk and Yishay Mansour.
The random sequence generated by LFSR can not guarantee the unpredictability in secure system and various methods have been proposed to improve its randomness [2] Despite this simplicity, there are currently no known attacks better than exhaustive search when the feedback polynomials are secret.
If the feedback polynomials are known, however, the best known attack requires less than A • S bits of output.
This example uses two Galois LFRSs to produce the output pseudorandom bitstream.
The Python code can be used to encrypt and decrypt a file or any bytestream.