From 1dac2263372df2b85db5d029a45721fa158a5c9d Mon Sep 17 00:00:00 2001 From: xiubuzhe Date: Sun, 8 Oct 2023 20:59:00 +0800 Subject: first add files --- lib/Crypto/Hash/HMAC.py | 213 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 213 insertions(+) create mode 100644 lib/Crypto/Hash/HMAC.py (limited to 'lib/Crypto/Hash/HMAC.py') diff --git a/lib/Crypto/Hash/HMAC.py b/lib/Crypto/Hash/HMAC.py new file mode 100644 index 0000000..e82bb9d --- /dev/null +++ b/lib/Crypto/Hash/HMAC.py @@ -0,0 +1,213 @@ +# +# HMAC.py - Implements the HMAC algorithm as described by RFC 2104. +# +# =================================================================== +# +# Copyright (c) 2014, Legrandin +# 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, tobytes + +from binascii import unhexlify + +from Crypto.Hash import MD5 +from Crypto.Hash import BLAKE2s +from Crypto.Util.strxor import strxor +from Crypto.Random import get_random_bytes + +__all__ = ['new', 'HMAC'] + + +class HMAC(object): + """An HMAC hash object. + Do not instantiate directly. Use the :func:`new` function. + + :ivar digest_size: the size in bytes of the resulting MAC tag + :vartype digest_size: integer + """ + + def __init__(self, key, msg=b"", digestmod=None): + + if digestmod is None: + digestmod = MD5 + + if msg is None: + msg = b"" + + # Size of the MAC tag + self.digest_size = digestmod.digest_size + + self._digestmod = digestmod + + if isinstance(key, memoryview): + key = key.tobytes() + + try: + if len(key) <= digestmod.block_size: + # Step 1 or 2 + key_0 = key + b"\x00" * (digestmod.block_size - len(key)) + else: + # Step 3 + hash_k = digestmod.new(key).digest() + key_0 = hash_k + b"\x00" * (digestmod.block_size - len(hash_k)) + except AttributeError: + # Not all hash types have "block_size" + raise ValueError("Hash type incompatible to HMAC") + + # Step 4 + key_0_ipad = strxor(key_0, b"\x36" * len(key_0)) + + # Start step 5 and 6 + self._inner = digestmod.new(key_0_ipad) + self._inner.update(msg) + + # Step 7 + key_0_opad = strxor(key_0, b"\x5c" * len(key_0)) + + # Start step 8 and 9 + self._outer = digestmod.new(key_0_opad) + + def update(self, msg): + """Authenticate the next chunk of message. + + Args: + data (byte string/byte array/memoryview): The next chunk of data + """ + + self._inner.update(msg) + return self + + def _pbkdf2_hmac_assist(self, first_digest, iterations): + """Carry out the expensive inner loop for PBKDF2-HMAC""" + + result = self._digestmod._pbkdf2_hmac_assist( + self._inner, + self._outer, + first_digest, + iterations) + return result + + def copy(self): + """Return a copy ("clone") of the HMAC object. + + The copy will have the same internal state as the original HMAC + object. + This can be used to efficiently compute the MAC tag of byte + strings that share a common initial substring. + + :return: An :class:`HMAC` + """ + + new_hmac = HMAC(b"fake key", digestmod=self._digestmod) + + # Syncronize the state + new_hmac._inner = self._inner.copy() + new_hmac._outer = self._outer.copy() + + return new_hmac + + def digest(self): + """Return the **binary** (non-printable) MAC tag of the message + authenticated so far. + + :return: The MAC tag digest, computed over the data processed so far. + Binary form. + :rtype: byte string + """ + + frozen_outer_hash = self._outer.copy() + frozen_outer_hash.update(self._inner.digest()) + return frozen_outer_hash.digest() + + def verify(self, mac_tag): + """Verify that a given **binary** MAC (computed by another party) + is valid. + + Args: + mac_tag (byte string/byte string/memoryview): the expected MAC of the message. + + Raises: + ValueError: if the MAC does not match. It means that the message + has been tampered with or that the MAC key is incorrect. + """ + + secret = get_random_bytes(16) + + mac1 = BLAKE2s.new(digest_bits=160, key=secret, data=mac_tag) + mac2 = BLAKE2s.new(digest_bits=160, key=secret, data=self.digest()) + + if mac1.digest() != mac2.digest(): + raise ValueError("MAC check failed") + + def hexdigest(self): + """Return the **printable** MAC tag of the message authenticated so far. + + :return: The MAC tag, computed over the data processed so far. + Hexadecimal encoded. + :rtype: string + """ + + return "".join(["%02x" % bord(x) + for x in tuple(self.digest())]) + + def hexverify(self, hex_mac_tag): + """Verify that a given **printable** MAC (computed by another party) + is valid. + + Args: + hex_mac_tag (string): the expected MAC of the message, + as a hexadecimal string. + + Raises: + ValueError: if the MAC does not match. It means that the message + has been tampered with or that the MAC key is incorrect. + """ + + self.verify(unhexlify(tobytes(hex_mac_tag))) + + +def new(key, msg=b"", digestmod=None): + """Create a new MAC object. + + Args: + key (bytes/bytearray/memoryview): + key for the MAC object. + It must be long enough to match the expected security level of the + MAC. + msg (bytes/bytearray/memoryview): + Optional. The very first chunk of the message to authenticate. + It is equivalent to an early call to :meth:`HMAC.update`. + digestmod (module): + The hash to use to implement the HMAC. + Default is :mod:`Crypto.Hash.MD5`. + + Returns: + An :class:`HMAC` object + """ + + return HMAC(key, msg, digestmod) -- cgit v1.2.3