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