95 lines
2.8 KiB
Python
95 lines
2.8 KiB
Python
# -*- coding: utf-8 -*-
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#
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# ===================================================================
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# The contents of this file are dedicated to the public domain. To
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# the extent that dedication to the public domain is not available,
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# everyone is granted a worldwide, perpetual, royalty-free,
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# non-exclusive license to exercise all rights associated with the
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# contents of this file for any purpose whatsoever.
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# No rights are reserved.
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#
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# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
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# BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
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# ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
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# CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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# SOFTWARE.
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# ===================================================================
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"""SHA-256 cryptographic hash algorithm.
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SHA-256 belongs to the SHA-2_ family of cryptographic hashes.
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It produces the 256 bit digest of a message.
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>>> from Crypto.Hash import SHA256
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>>>
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>>> h = SHA256.new()
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>>> h.update(b'Hello')
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>>> print h.hexdigest()
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*SHA* stands for Secure Hash Algorithm.
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.. _SHA-2: http://csrc.nist.gov/publications/fips/fips180-2/fips180-2.pdf
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"""
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_revision__ = "$Id$"
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__all__ = ['new', 'digest_size', 'SHA256Hash' ]
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from Crypto.Util.py3compat import *
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from Crypto.Hash.hashalgo import HashAlgo
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try:
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import hashlib
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hashFactory = hashlib.sha256
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except ImportError:
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from Crypto.Hash import _SHA256
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hashFactory = _SHA256
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class SHA256Hash(HashAlgo):
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"""Class that implements a SHA-256 hash
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:undocumented: block_size
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"""
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#: ASN.1 Object identifier (OID)::
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#:
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#: id-sha256 OBJECT IDENTIFIER ::= {
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#: joint-iso-itu-t(2) country(16) us(840) organization(1)
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#: gov(101) csor(3) nistalgorithm(4) hashalgs(2) 1
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#: }
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#:
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#: This value uniquely identifies the SHA-256 algorithm.
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oid = b('\x06\x09\x60\x86\x48\x01\x65\x03\x04\x02\x01')
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digest_size = 32
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block_size = 64
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def __init__(self, data=None):
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HashAlgo.__init__(self, hashFactory, data)
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def new(self, data=None):
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return SHA256Hash(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 `SHA256Hash.update()`.
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Optional.
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:Return: A `SHA256Hash` object
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"""
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return SHA256Hash().new(data)
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#: The size of the resulting hash in bytes.
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digest_size = SHA256Hash.digest_size
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#: The internal block size of the hash algorithm in bytes.
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block_size = SHA256Hash.block_size
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