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