def test_signature(self):
k1 = new_key()
k2 = new_key()
k3 = new_key()
sender = Encryptor(k1, k2.publickey())
receiver = Encryptor(k2, k1.publickey())
deceiver = Encryptor(k3, k2.publickey())
message = b"Erised stra ehru oyt ube cafru oyt on wohsi"
with print_key_on_error(sender, receiver, deceiver):
cipher_text = sender.encrypt(message)
decrypted_message, signature = receiver.decrypt(cipher_text)
self.assertTrue(receiver.verify_message(decrypted_message, signature))
deceiver_text = deceiver.encrypt(message)
decrypted_message, signature = receiver.decrypt(deceiver_text)
self.assertFalse(receiver.verify_message(decrypted_message, signature))
_, real_encrypted_message, _ = receiver.split_cipher_text(cipher_text)
deceiver_aes, _, deceiver_signature = receiver.split_cipher_text(deceiver_text)
cipher_text = deceiver_aes + real_encrypted_message + deceiver_signature
decrypted_message, signature = receiver.decrypt(cipher_text)
self.assertFalse(receiver.verify_message(decrypted_message, signature))
