def test_single_xor_empty_s_returns_unchanged_bytes(self):
b = b'Hey'
expected_bytes = b'Hey'
actual_bytes = single_xor(b, b'')
self.assertEqual(expected_bytes, actual_bytes)
def test_single_xor_s_more_than_one_byte_only_first_byte_is_used(self):
b = b'Hey'
s = b'Aloha'
expected_bytes = b'\x09\x24\x38'
actual_bytes = single_xor(b, s)
self.assertEqual(expected_bytes, actual_bytes)
def test_single_xor_nominal_case(self):
b = b'Hey'
s = b'A'
expected_bytes = b'\x09\x24\x38'
actual_bytes = single_xor(b, s)
self.assertEqual(expected_bytes, actual_bytes)
def break_single_xor(encrypted: bytes) -> list:
"""
params:
encrypted: bytes encrypted using single-xor
returns:
list of dict {'message': bytes, 'key': bytes: 'score': float}
sorted in descending order by score
"""
res = list()
for i in range(0, 256):
b = i.to_bytes(1, byteorder=sys.byteorder)
xored = single_xor(encrypted, b)
score = freq_score(xored)
res.append({'message': xored, 'key': b, 'score': score})
res.sort(key=lambda d: d['score'], reverse=True)
return res
def test_single_xor_none_input_raises_typeerror(self):
with self.assertRaises(TypeError):
single_xor(None, b'A')
def test_single_xor_empty_input_returns_empty_bytes(self):
self.assertEqual(single_xor(b'', b'A'), b'')