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# ===================================================================
#
# Copyright (c) 2021, 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 is_bytes
from .KMAC128 import KMAC_Hash
from . import cSHAKE256
def new(**kwargs):
"""Create a new KMAC256 object.
Args:
key (bytes/bytearray/memoryview):
The key to use to compute the MAC.
It must be at least 256 bits long (32 bytes).
data (bytes/bytearray/memoryview):
Optional. The very first chunk of the message to authenticate.
It is equivalent to an early call to :meth:`KMAC_Hash.update`.
mac_len (integer):
Optional. The size of the authentication tag, in bytes.
Default is 64. Minimum is 8.
custom (bytes/bytearray/memoryview):
Optional. A customization byte string (``S`` in SP 800-185).
Returns:
A :class:`KMAC_Hash` hash object
"""
key = kwargs.pop("key", None)
if not is_bytes(key):
raise TypeError("You must pass a key to KMAC256")
if len(key) < 32:
raise ValueError("The key must be at least 256 bits long (32 bytes)")
data = kwargs.pop("data", None)
mac_len = kwargs.pop("mac_len", 64)
if mac_len < 8:
raise ValueError("'mac_len' must be 8 bytes or more")
custom = kwargs.pop("custom", b"")
if kwargs:
raise TypeError("Unknown parameters: " + str(kwargs))
return KMAC_Hash(data, key, mac_len, custom, "20", cSHAKE256, 136)
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