Edit File: keccak.py
# =================================================================== # # Copyright (c) 2015, Legrandin <helderijs@gmail.com> # All rights reserved. # # Redistribution and use in source and binary forms, with or without # modification, are permitted provided that the following conditions # are met: # # 1. Redistributions of source code must retain the above copyright # notice, this list of conditions and the following disclaimer. # 2. Redistributions in binary form must reproduce the above copyright # notice, this list of conditions and the following disclaimer in # the documentation and/or other materials provided with the # distribution. # # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS # "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT # LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS # FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE # COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, # INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, # BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; # LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER # CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT # LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN # ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE # POSSIBILITY OF SUCH DAMAGE. # =================================================================== from Crypto.Util.py3compat import bord from Crypto.Util._raw_api import (load_pycryptodome_raw_lib, VoidPointer, SmartPointer, create_string_buffer, get_raw_buffer, c_size_t, c_uint8_ptr, c_ubyte) _raw_keccak_lib = load_pycryptodome_raw_lib("Crypto.Hash._keccak", """ int keccak_init(void **state, size_t capacity_bytes, uint8_t rounds); int keccak_destroy(void *state); int keccak_absorb(void *state, const uint8_t *in, size_t len); int keccak_squeeze(const void *state, uint8_t *out, size_t len, uint8_t padding); int keccak_digest(void *state, uint8_t *digest, size_t len, uint8_t padding); int keccak_copy(const void *src, void *dst); int keccak_reset(void *state); """) class Keccak_Hash(object): """A Keccak hash object. Do not instantiate directly. Use the :func:`new` function. :ivar digest_size: the size in bytes of the resulting hash :vartype digest_size: integer """ def __init__(self, data, digest_bytes, update_after_digest): # The size of the resulting hash in bytes. self.digest_size = digest_bytes self._update_after_digest = update_after_digest self._digest_done = False self._padding = 0x01 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 keccak" % result) self._state = SmartPointer(state.get(), _raw_keccak_lib.keccak_destroy) if data: self.update(data) def update(self, data): """Continue hashing of a message by consuming the next chunk of data. Args: data (byte string/byte array/memoryview): The next chunk of the message being hashed. """ if self._digest_done and not self._update_after_digest: raise TypeError("You can only call 'digest' or 'hexdigest' on this object") result = _raw_keccak_lib.keccak_absorb(self._state.get(), c_uint8_ptr(data), c_size_t(len(data))) if result: raise ValueError("Error %d while updating keccak" % result) return self 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 hexdigest(self): """Return the **printable** digest of the message that has been hashed so far. :return: The hash digest, computed over the data processed so far. Hexadecimal encoded. :rtype: string """ return "".join(["%02x" % bord(x) for x in self.digest()]) def new(self, **kwargs): """Create a fresh Keccak hash object.""" if "digest_bytes" not in kwargs and "digest_bits" not in kwargs: kwargs["digest_bytes"] = self.digest_size return new(**kwargs) def new(**kwargs): """Create a new hash object. Args: data (bytes/bytearray/memoryview): The very first chunk of the message to hash. It is equivalent to an early call to :meth:`Keccak_Hash.update`. digest_bytes (integer): The size of the digest, in bytes (28, 32, 48, 64). digest_bits (integer): The size of the digest, in bits (224, 256, 384, 512). update_after_digest (boolean): Whether :meth:`Keccak.digest` can be followed by another :meth:`Keccak.update` (default: ``False``). :Return: A :class:`Keccak_Hash` hash object """ data = kwargs.pop("data", None) update_after_digest = kwargs.pop("update_after_digest", False) digest_bytes = kwargs.pop("digest_bytes", None) digest_bits = kwargs.pop("digest_bits", None) if None not in (digest_bytes, digest_bits): raise TypeError("Only one digest parameter must be provided") if (None, None) == (digest_bytes, digest_bits): raise TypeError("Digest size (bits, bytes) not provided") if digest_bytes is not None: if digest_bytes not in (28, 32, 48, 64): raise ValueError("'digest_bytes' must be: 28, 32, 48 or 64") else: if digest_bits not in (224, 256, 384, 512): raise ValueError("'digest_bytes' must be: 224, 256, 384 or 512") digest_bytes = digest_bits // 8 if kwargs: raise TypeError("Unknown parameters: " + str(kwargs)) return Keccak_Hash(data, digest_bytes, update_after_digest)
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