LFSR

lfsr.py

from collections import deque
from typing import List


def fibonacci(seed: int, taps: List[int]):
    """Fibonacci Linear Feedback Shift Register"""
    if not taps:
        raise ValueError('Unable to create LFSR without taps.')

    size = len(bin(seed)[2:])
    if any(x > size for x in taps):
        raise ValueError('Invalid tap provided, it exceeds the size of the seed.')

    state = deque([int(x) for x in format(seed, f'0{size}b')], maxlen=size)
    while True:
        v = 0
        for idx in reversed(taps):
            v ^= state[idx - 1]
        yield state.pop()
        state.appendleft(v)


if __name__ == '__main__':
    try:
        for value in fibonacci(44257, [11, 13, 14, 16]):
            print(value, end='')
    except KeyboardInterrupt:
        pass