Test implementation of a polynomial scrambler used in modems and fax machines

scrambler.py

# Test implementation of a polynomial scrambler used in modems and fax machines as explained in 
# http://i56578-swl.blogspot.com/2018/03/scrambling-and-descrambling.html
class PolynomialScrambler():	
	def __init__(self, degrees):
		self.degrees = sorted(degrees)
		self.step = 0
		self.bits = [0] * max(degrees)

	def state(self):
		return " ".join(map(str, self.bits))

	def shift_and_set_first_bit(self, new_first_bit):
		self.bits = [new_first_bit] + self.bits[:-1]

	def scramble(self, bit):
		print("step % 5d : input %s - %s" % (self.step, bit, self.state()), end = '')
		self.step += 1

		output = None
		for d in self.degrees:
			if output is None:
				output = self.bits[d - 1]
			else:
				output = output ^ self.bits[d - 1]

		# + 1
		output = output ^ 1

		self.shift_and_set_first_bit(output)

		print("- output %s" % output)

s = PolynomialScrambler([10, 1])
for x in range(20):
	s.scramble(1)