188 lines
6.5 KiB
Python
188 lines
6.5 KiB
Python
# ===================================================================
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#
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# Copyright (c) 2014, Legrandin <helderijs@gmail.com>
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# All rights reserved.
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#
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# Redistribution and use in source and binary forms, with or without
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# modification, are permitted provided that the following conditions
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# are met:
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#
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# 1. Redistributions of source code must retain the above copyright
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# notice, this list of conditions and the following disclaimer.
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# 2. Redistributions in binary form must reproduce the above copyright
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# notice, this list of conditions and the following disclaimer in
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# the documentation and/or other materials provided with the
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# distribution.
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#
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# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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# FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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# COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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# INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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# BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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# LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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# CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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# ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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# POSSIBILITY OF SUCH DAMAGE.
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# ===================================================================
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"""
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MD2 cryptographic hash algorithm.
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MD2 is specified in RFC1319_ and it produces the 128 bit digest of a message.
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>>> from Crypto.Hash import MD2
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>>>
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>>> h = MD2.new()
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>>> h.update(b'Hello')
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>>> print h.hexdigest()
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MD2 stand for Message Digest version 2, and it was invented by Rivest in 1989.
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This algorithm is both slow and insecure. Do not use it for new designs.
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.. _RFC1319: http://tools.ietf.org/html/rfc1319
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"""
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from Crypto.Util.py3compat import bord
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from Crypto.Util._raw_api import (load_pycryptodome_raw_lib,
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VoidPointer, SmartPointer,
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create_string_buffer,
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get_raw_buffer, c_size_t,
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expect_byte_string)
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_raw_md2_lib = load_pycryptodome_raw_lib(
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"Crypto.Hash._MD2",
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"""
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int md2_init(void **shaState);
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int md2_destroy(void *shaState);
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int md2_update(void *hs,
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const uint8_t *buf,
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size_t len);
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int md2_digest(const void *shaState,
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uint8_t digest[20]);
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int md2_copy(const void *src, void *dst);
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""")
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class MD2Hash(object):
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"""Class that implements an MD2 hash
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"""
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#: The size of the resulting hash in bytes.
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digest_size = 16
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#: The internal block size of the hash algorithm in bytes.
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block_size = 64
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#: ASN.1 Object ID
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oid = "1.2.840.113549.2.2"
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def __init__(self, data=None):
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state = VoidPointer()
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result = _raw_md2_lib.md2_init(state.address_of())
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if result:
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raise ValueError("Error %d while instantiating MD2"
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% result)
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self._state = SmartPointer(state.get(),
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_raw_md2_lib.md2_destroy)
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if data:
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self.update(data)
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def update(self, data):
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"""Continue hashing of a message by consuming the next chunk of data.
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Repeated calls are equivalent to a single call with the concatenation
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of all the arguments. In other words:
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>>> m.update(a); m.update(b)
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is equivalent to:
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>>> m.update(a+b)
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:Parameters:
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data : byte string
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The next chunk of the message being hashed.
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"""
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expect_byte_string(data)
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result = _raw_md2_lib.md2_update(self._state.get(),
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data,
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c_size_t(len(data)))
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if result:
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raise ValueError("Error %d while instantiating MD2"
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% result)
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def digest(self):
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"""Return the **binary** (non-printable) digest of the message that
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has been hashed so far.
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This method does not change the state of the hash object.
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You can continue updating the object after calling this function.
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:Return: A byte string of `digest_size` bytes. It may contain non-ASCII
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characters, including null bytes.
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"""
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bfr = create_string_buffer(self.digest_size)
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result = _raw_md2_lib.md2_digest(self._state.get(),
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bfr)
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if result:
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raise ValueError("Error %d while instantiating MD2"
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% result)
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return get_raw_buffer(bfr)
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def hexdigest(self):
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"""Return the **printable** digest of the message that has been
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hashed so far.
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This method does not change the state of the hash object.
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:Return: A string of 2* `digest_size` characters. It contains only
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hexadecimal ASCII digits.
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"""
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return "".join(["%02x" % bord(x) for x in self.digest()])
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def copy(self):
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"""Return a copy ("clone") of the hash object.
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The copy will have the same internal state as the original hash
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object.
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This can be used to efficiently compute the digests of strings that
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share a common initial substring.
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:Return: A hash object of the same type
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"""
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clone = MD2Hash()
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result = _raw_md2_lib.md2_copy(self._state.get(),
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clone._state.get())
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if result:
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raise ValueError("Error %d while copying MD2" % result)
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return clone
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def new(self, data=None):
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return MD2Hash(data)
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def new(data=None):
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"""Return a fresh instance of the hash object.
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:Parameters:
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data : byte string
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The very first chunk of the message to hash.
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It is equivalent to an early call to `MD2Hash.update()`.
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Optional.
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:Return: A `MD2Hash` object
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"""
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return MD2Hash().new(data)
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#: The size of the resulting hash in bytes.
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digest_size = MD2Hash.digest_size
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#: The internal block size of the hash algorithm in bytes.
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block_size = MD2Hash.block_size
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