def read(self, length):
"""
Compute the next piece of XOF output.
.. note::
You cannot use :meth:`update` anymore after the first call to
:meth:`read`.
Args:
length (integer): the amount of bytes this method must return
:return: the next piece of XOF output (of the given length)
:rtype: byte string
"""
self._is_squeezing = True
bfr = create_string_buffer(length)
result = _raw_keccak_lib.keccak_squeeze(self._state.get(),
bfr,
c_size_t(length),
c_ubyte(self._padding))
if result:
raise ValueError("Error %d while extracting from SHAKE128"
% result)
return get_raw_buffer(bfr)
def _create_keccak(self):
state = VoidPointer()
result = _raw_keccak_lib.keccak_init(state.address_of(),
c_size_t(32), # 32 bytes of capacity (256 bits)
c_ubyte(12)) # Reduced number of rounds
if result:
raise ValueError("Error %d while instantiating KangarooTwelve"
% result)
return SmartPointer(state.get(), _raw_keccak_lib.keccak_destroy)
def _squeeze(self, hash_obj, length, padding):
bfr = create_string_buffer(length)
result = _raw_keccak_lib.keccak_squeeze(hash_obj.get(),
bfr,
c_size_t(length),
c_ubyte(padding))
if result:
raise ValueError("Error %d while extracting from KangarooTwelve"
% result)
return get_raw_buffer(bfr)
def __init__(self, data=None):
state = VoidPointer()
result = _raw_keccak_lib.keccak_init(state.address_of(), c_size_t(64),
c_ubyte(24))
if result:
raise ValueError("Error %d while instantiating SHAKE256" % result)
self._state = SmartPointer(state.get(), _raw_keccak_lib.keccak_destroy)
self._is_squeezing = False
self._padding = 0x1F
if data:
self.update(data)
def __init__(self, data, update_after_digest):
self._update_after_digest = update_after_digest
self._digest_done = False
self._padding = 0x06
state = VoidPointer()
result = _raw_keccak_lib.keccak_init(state.address_of(),
c_size_t(self.digest_size * 2),
c_ubyte(24))
if result:
raise ValueError("Error %d while instantiating SHA-3/512" % result)
self._state = SmartPointer(state.get(), _raw_keccak_lib.keccak_destroy)
if data:
self.update(data)
def digest(self):
"""Return the **binary** (non-printable) digest of the message that has been hashed so far.
:return: The hash digest, computed over the data processed so far.
Binary form.
:rtype: byte string
"""
self._digest_done = True
bfr = create_string_buffer(self.digest_size)
result = _raw_keccak_lib.keccak_digest(self._state.get(),
bfr,
c_size_t(self.digest_size),
c_ubyte(self._padding))
if result:
raise ValueError("Error %d while squeezing keccak" % result)
return get_raw_buffer(bfr)
def __init__(self, data, custom, capacity, function):
state = VoidPointer()
if custom or function:
prefix_unpad = _encode_str(function) + _encode_str(custom)
prefix = _bytepad(prefix_unpad, (1600 - capacity) // 8)
self._padding = 0x04
else:
prefix = None
self._padding = 0x1F # for SHAKE
result = _raw_keccak_lib.keccak_init(state.address_of(),
c_size_t(capacity // 8),
c_ubyte(24))
if result:
raise ValueError("Error %d while instantiating cSHAKE" % result)
self._state = SmartPointer(state.get(), _raw_keccak_lib.keccak_destroy)
self._is_squeezing = False
if prefix:
self.update(prefix)
if data:
self.update(data)
