def _get_offset(self, message):
initial_block_length = self._get_block_length(message)
pad_size = 1
while True:
padding_chars = [
random.choice(self.padding_chars) for _ in range(pad_size)
]
padding = Concatenation(padding_chars).value()
block_length = self._get_block_length(message + padding)
if block_length == initial_block_length + 1:
return len(padding)
pad_size += 1
def value(self):
suffix = [str() for _ in range(self.length)]
biased_byte_position = self.BIASED_BYTE_1[0]
for i in range(1 + self.length/2):
# Generate a prefix long enough to place the ith byte of the
# ciphertext in position 15 and the jth byte in position 31.
j = i + biased_byte_position + 1
prefix_length = self.length - j + 1
byte_i, byte_j = self._decrypt_bytes(prefix_length)
suffix[i] = byte_i
if j < self.length:
suffix[j] = byte_j
return Concatenation(suffix).value()
def _value(self, string):
bin_strings = map(self._to_bin, string)
return Concatenation(bin_strings).value()
def _compute_value(self):
registers = map(self._to_bytes, self.registers)
return Concatenation(registers).value()
def rand_bytes(self, count):
int_count = int(ceil(count / 4.0))
integers = [self.rand() for _ in range(int_count)]
int_bytes = map(lambda integer: IntToBytes(integer).value(), integers)
return Concatenation(int_bytes).value()[:count]
def _get_challenge_classes(self):
challenge_classes = MatasanoChallenge.__subclasses__()
challenge_classes = map(self._get_proper_classes, challenge_classes)
return Concatenation(challenge_classes).value()
def expected_value(self):
decoded_lines = Base64Decoder().decode_file_lines(self.ANSWER_FILE)
return Concatenation(decoded_lines).value()
def value(self):
min_length = min(map(len, self.strings))
strings = [string[:min_length] for string in self.strings]
return Concatenation(strings).value()
def hash(self, message):
hashes = map(lambda function: function().hash(message), self.functions)
return Concatenation(hashes).value()
def _build_message_from(self, words):
endianness = self.md4.endianness()
words = map(lambda word: endianness.from_int(word, 4).value(), words)
return Concatenation(words).value()