99 lines
3.0 KiB
Python
99 lines
3.0 KiB
Python
# -*- coding: ascii -*-
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#
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# Random/Fortuna/SHAd256.py : SHA_d-256 hash function implementation
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#
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# Written in 2008 by Dwayne C. Litzenberger <dlitz@dlitz.net>
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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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"""\
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SHA_d-256 hash function implementation.
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This module should comply with PEP 247.
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"""
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__revision__ = "$Id$"
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__all__ = ['new', 'digest_size']
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import sys
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if sys.version_info[0] == 2 and sys.version_info[1] == 1:
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from Crypto.Util.py21compat import *
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from Crypto.Util.py3compat import *
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from binascii import b2a_hex
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from Crypto.Hash import SHA256
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assert SHA256.digest_size == 32
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class _SHAd256(object):
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"""SHA-256, doubled.
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Returns SHA-256(SHA-256(data)).
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"""
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digest_size = SHA256.digest_size
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_internal = object()
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def __init__(self, internal_api_check, sha256_hash_obj):
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if internal_api_check is not self._internal:
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raise AssertionError("Do not instantiate this class directly. Use %s.new()" % (__name__,))
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self._h = sha256_hash_obj
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# PEP 247 "copy" method
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def copy(self):
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"""Return a copy of this hashing object"""
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return _SHAd256(SHAd256._internal, self._h.copy())
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# PEP 247 "digest" method
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def digest(self):
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"""Return the hash value of this object as a binary string"""
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retval = SHA256.new(self._h.digest()).digest()
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assert len(retval) == 32
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return retval
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# PEP 247 "hexdigest" method
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def hexdigest(self):
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"""Return the hash value of this object as a (lowercase) hexadecimal string"""
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retval = b2a_hex(self.digest())
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assert len(retval) == 64
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if sys.version_info[0] == 2:
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return retval
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else:
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return retval.decode()
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# PEP 247 "update" method
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def update(self, data):
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self._h.update(data)
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# PEP 247 module-level "digest_size" variable
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digest_size = _SHAd256.digest_size
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# PEP 247 module-level "new" function
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def new(data=None):
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"""Return a new SHAd256 hashing object"""
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if not data:
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data=b("")
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sha = _SHAd256(_SHAd256._internal, SHA256.new(data))
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sha.new = globals()['new']
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return sha
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# vim:set ts=4 sw=4 sts=4 expandtab:
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