Simple RSA implementation in Python

rsa.py

from math import gcd

class ID:
  def __init__(self, p = 53, q = 59):
    self.__p = p
    self.__q = q

  @property
  def __phi(self) -> int:
    return (self.__p - 1) * (self.__q - 1)

  @property
  def __d(self) -> int:
    return pow(self.e, -1, self.__phi)

  @property
  def e(self) -> int:
    for n in range(2, self.__phi):
      if gcd(n, self.__phi) == 1:
        return n

  @property
  def N(self) -> int:
    return self.__p * self.__q

  def encrypt(self, m: int, recipient):
    return pow(m, recipient.e, recipient.N)

  def decrypt(self, m: int):
    return pow(m, self.__d, self.N)

def main():
  alice = ID()
  bob = ID(61, 73)

  original = 20
  m = alice.encrypt(original, bob)
  r = bob.decrypt(m)

  print(r)
  assert r == original

if __name__ == '__main__':
  main()