solver.py

import codecs
from Crypto.PublicKey import RSA
from Crypto.Util.number import long_to_bytes
from crypto_commons.generic import bytes_to_long
from crypto_commons.rsa.rsa_commons import gcd, get_fi_distinct_primes, modinv


def read_ct():
    with codecs.open("cipher", "rb") as input_file:
        data = input_file.read()
        print(len(data))
        msg = bytes_to_long(data)
    return msg


def read_key(filename):
    with codecs.open(filename, "r") as input_file:
        data = input_file.read()
        pub = RSA.importKey(data)
        print(pub.e, pub.n)
    return pub


def main():
    pub1 = read_key("pub1.pub")
    pub2 = read_key("pub2.pub")
    p = gcd(pub1.n, pub2.n)
    print(p)
    q1 = pub1.n / p
    q2 = pub2.n / p
    print(p, q1)
    print(p, q2)
    msg = read_ct()

    d1 = modinv(pub1.e, get_fi_distinct_primes([p, q1]))
    d2 = modinv(pub2.e, get_fi_distinct_primes([p, q2]))

    first = pow(msg, d1, pub1.n)
    print(long_to_bytes(first))


main()