def test_cmac_subkeys():
k = binascii.unhexlify("8195088CE6C393708EBBE6C7914ECB0B")
kx = binascii.unhexlify("2D22571A33B2965A9B49FF4395A43046")
k0 = LRP.eval_lrp(LRP.generate_plaintexts(k),
LRP.generate_updated_keys(k)[0], b"\x00" * 16, True)
assert (_Element(k0) * _Element(4)).encode().hex() == kx.hex()
def test4(self):
# Test inversion
one = _Element(1)
x = one.inverse()
self.assertEqual(int(x), 1)
x = _Element(82323923)
y = x.inverse()
self.assertEqual(int(x * y), 1)
def test4(self):
# Test inversion
one = _Element(1)
x = one.inverse()
self.assertEqual(int(x), 1)
x = _Element(82323923)
y = x.inverse()
self.assertEqual(int(x * y), 1)
def test1(self):
# Test encondings
e = _Element(256)
self.assertEqual(int(e), 256)
self.assertEqual(e.encode(), bchr(0) * 14 + b("\x01\x00"))
e = _Element(bchr(0) * 14 + b("\x01\x10"))
self.assertEqual(int(e), 0x110)
self.assertEqual(e.encode(), bchr(0) * 14 + b("\x01\x10"))
# Only 16 byte string are a valid encoding
self.assertRaises(ValueError, _Element, bchr(0))
def test1(self):
# Test encondings
e = _Element(256)
self.assertEqual(int(e), 256)
self.assertEqual(e.encode(), bchr(0)*14 + b("\x01\x00"))
e = _Element(bchr(0)*14 + b("\x01\x10"))
self.assertEqual(int(e), 0x110)
self.assertEqual(e.encode(), bchr(0)*14 + b("\x01\x10"))
# Only 16 byte string are a valid encoding
self.assertRaises(ValueError, _Element, bchr(0))
def test3(self):
# Test multiplication
zero = _Element(0)
one = _Element(1)
two = _Element(2)
x = _Element(6) * zero
self.assertEqual(int(x), 0)
x = _Element(6) * one
self.assertEqual(int(x), 6)
x = _Element(2L**127) * two
self.assertEqual(int(x), 1 + 2 + 4 + 128)
def cmac(self, data: bytes) -> bytes:
"""
Calculate CMAC_LRP
(Huge thanks to @Pharisaeus for help with polynomial math.)
:param data: message to be authenticated
:return: CMAC result
"""
stream = io.BytesIO(data)
k0 = LRP.eval_lrp(self.p, self.kp, b"\x00" * 16, True)
k1 = (_Element(k0) * _Element(2)).encode()
k2 = (_Element(k0) * _Element(4)).encode()
y = b"\x00" * AES.block_size
while True:
x = stream.read(AES.block_size)
if len(x) < AES.block_size or stream.tell() == stream.getbuffer(
).nbytes:
break
y = strxor(x, y)
y = LRP.eval_lrp(self.p, self.kp, y, True)
pad_bytes = 0
if len(x) < AES.block_size:
pad_bytes = AES.block_size - len(x)
x = x + b"\x80" + (b"\x00" * (pad_bytes - 1))
y = strxor(x, y)
if not pad_bytes:
y = strxor(y, k1)
else:
y = strxor(y, k2)
return LRP.eval_lrp(self.p, self.kp, y, True)
def test2(self):
# Test addition
e = _Element(0x10)
f = _Element(0x0A)
self.assertEqual(int(e + f), 0x1A)
def test2(self):
# Test addition
e = _Element(0x10)
f = _Element(0x0A)
self.assertEqual(int(e+f), 0x1A)
