pyUmbral/tests/test_dem.py

61 lines
1.6 KiB
Python

import pytest
import os
from umbral.dem import UmbralDEM, DEM_KEYSIZE, DEM_NONCE_SIZE
from cryptography.exceptions import InvalidTag
def test_encrypt_decrypt():
key = os.urandom(32)
dem = UmbralDEM(key)
plaintext = b'peace at dawn'
ciphertext0 = dem.encrypt(plaintext)
ciphertext1 = dem.encrypt(plaintext)
assert ciphertext0 != plaintext
assert ciphertext1 != plaintext
# Ciphertext should be different even with same plaintext.
assert ciphertext0 != ciphertext1
# Nonce should be different
assert ciphertext0[:DEM_NONCE_SIZE] != ciphertext1[:DEM_NONCE_SIZE]
cleartext0 = dem.decrypt(ciphertext0)
cleartext1 = dem.decrypt(ciphertext1)
assert cleartext0 == plaintext
assert cleartext1 == plaintext
def test_encrypt_decrypt_associated_data():
key = os.urandom(32)
aad = b'secret code 1234'
dem = UmbralDEM(key)
plaintext = b'peace at dawn'
ciphertext0 = dem.encrypt(plaintext, authenticated_data=aad)
ciphertext1 = dem.encrypt(plaintext, authenticated_data=aad)
assert ciphertext0 != plaintext
assert ciphertext1 != plaintext
assert ciphertext0 != ciphertext1
assert ciphertext0[:DEM_NONCE_SIZE] != ciphertext1[:DEM_NONCE_SIZE]
cleartext0 = dem.decrypt(ciphertext0, authenticated_data=aad)
cleartext1 = dem.decrypt(ciphertext1, authenticated_data=aad)
assert cleartext0 == plaintext
assert cleartext1 == plaintext
# Attempt decryption with invalid associated data
with pytest.raises(InvalidTag):
cleartext2 = dem.decrypt(ciphertext0, authenticated_data=b'wrong data')