def test_basic():
key = base64.urlsafe_b64encode(os.urandom(16))
aes = AESCtr(key)
txt = b'A great Secret message' * 12 # To make it larger than 128-bit
ctx = aes.encrypt(txt)
dtxt = aes.decrypt(ctx)
assert dtxt == txt, "The decrypted text is not the same as the original text"
def test_ctxdist2(): """ Test 1: Cipher text of different messages are different """ n = 1000 key = base64.urlsafe_b64encode(os.urandom(16)) aes = AESCtr(key) next_ctx = lambda : aes.encrypt(os.urandom(1000))[:8] assert len(list(set(next_ctx() for i in xrange(n)))) == n, "Repeating whole ciphertext for differet messages!"
def test_basic():
"""
Test: dec(enc(txt)) == txt, and
Test: len(ctx) = len(txt) + 8 (8 is for the nonce/IV)
(Note, if you use padding disable the length check test
"""
key = base64.urlsafe_b64encode(os.urandom(16))
aes = AESCtr(key)
testtxt = ['a', 'ab', '', 'A great Secret message'*12, '0'*10000]
for txt in testtxt:
ctx = aes.encrypt(txt)
dtxt = aes.decrypt(ctx)
assert len(ctx) - len(txt) == aes._nonce_size # Disable this test if you are using pading
assert dtxt==txt, "The decrypted text is not the same as the original text"
def test_keyvalid():
"""
Wrong key should output junk.
"""
n = 1000
key = base64.urlsafe_b64encode(os.urandom(16))
aes = AESCtr(key)
txt = os.urandom(1000)
ctx = aes.encrypt(txt)
def next_ctx():
key = base64.urlsafe_b64encode(os.urandom(16))
aes = AESCtr(key)
return aes.decrypt(ctx)
output_ptxt = set(next_ctx() for i in xrange(n))
assert txt not in output_ptxt, "Decryption output same for different key!"
assert len(output_ptxt) == n, "Repeating whole ciphertext for differet keys!"
def test_ctxdist1():
"""
Test 1: All the blocks in the cipher text should be unique (with very high probability).
Test 2: Encrypting the same message 1000 times should return 1000 different ciphertexts.
"""
key = base64.urlsafe_b64encode(os.urandom(16))
aes = AESCtr(key)
txt = 'a'*2000
# remove the IV, otherwise the ctx will be trivially different.
n = 1000
ctx = aes.encrypt(txt)[8:]
num_unique_blocks = len(set(ctx[i:i+aes._block_size_bytes] \
for i in xrange(0, len(ctx), aes._block_size_bytes)))
num_blocks = len(txt[::aes._block_size_bytes])
assert num_blocks == num_unique_blocks, "Repeating ciphertext blocks"
# There should not be any repeat. If they are not same, then most
# probably the ciphertexts are random
assert len(list(set(aes.encrypt(txt)[8:] for i in xrange(n)))) == n, "Repeating whole ciphertext!"
def next_ctx(): key = base64.urlsafe_b64encode(os.urandom(16)) aes = AESCtr(key) return aes.decrypt(ctx)
