def test_sign_and_verify():
# Setting up the RSA cryptosystem for the test
p = random_prime(2 ** 512)
q = random_prime(2 ** 512)
n = Integer(p * q)
phi = (p - 1) * (q - 1)
e = Integer(65537)
bezout = xgcd(e, phi)
d = Integer(mod(bezout[1], phi))
assert mod(d * e, phi) == 1
# First create an instance of RSASign
signer = RSASign(None, d, n)
# Then sign a message
signed_message = signer.sign("blah")
# Craft the final message
final_message = str(signed_message) + "@" + "blah"
# Verify the final message
verifier = RSAVerify(None, e, n)
if not verifier.verify(final_message):
print "Message has been tampered with, unable to validate"
else:
print "Message validated"
