Testing out an RSA logic script with super low primes

rsa.py

import sys

sys.setrecursionlimit(100)


def eea(stuff, thing):
    if stuff != 0:
        (gcd, s, t) = eea(thing % stuff, stuff)

        return gcd, t - (thing // stuff) * s, s  # // is quotient only division
    else:
        return thing, 0, 1


def inversemod(number, mod):
    (gcd, s, t) = eea(number, mod)

    if gcd == 1:
        return s % mod
    else:
        return None  # modular inverse can only be found if numbers are coprime


e = 7
p = 11
q = 13
n = p * q
phi = (p - 1) * (q - 1)


def encrypt(message):
    return (message ** e) % n


d = inversemod(e, phi)


def decrypt(cipher):
    return (cipher ** d) % n


print('n: ' + str(n))
print('phi: ' + str(phi))
print('d: ' + str(d))
print

if e == 7 and p == 11 and q == 13:
    print(d == 103)
    print

print('public: (' + str(e) + ',' + str(n) + ')')
print('private: (' + str(d) + ',' + str(n) + ')')

n: 143
phi: 120
d: 103

True

public: (7,143)
private: (103,143)