# ===================================================================
#
# 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
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# ===================================================================
from Cryptodome.Util.py3compat import bord
from Cryptodome.Util._raw_api import (load_pycryptodome_raw_lib,
VoidPointer, SmartPointer,
create_string_buffer,
get_raw_buffer, c_size_t,
c_uint8_ptr)
_raw_keccak_lib = load_pycryptodome_raw_lib("Cryptodome.Hash._keccak",
"""
int keccak_init(void **state,
size_t capacity_bytes,
uint8_t padding_byte);
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);
int keccak_digest(void *state, uint8_t *digest, size_t len);
""")
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
state = VoidPointer()
result = _raw_keccak_lib.keccak_init(state.address_of(),
c_size_t(self.digest_size * 2),
0x01)
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))
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)