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# Slixmpp: The Slick XMPP Library
# Copyright (C) 2017 Emmanuel Gil Peyrot
# This file is part of Slixmpp.
# See the file LICENSE for copying permission.
from base64 import b64encode
import hashlib
import logging
from slixmpp.plugins import BasePlugin
from slixmpp.plugins.xep_0300 import stanza, Hash
log = logging.getLogger(__name__)
class XEP_0300(BasePlugin):
"""
XEP-0300: Use of Cryptographic Hash Functions in XMPP
"""
name = 'xep_0300'
description = 'XEP-0300: Use of Cryptographic Hash Functions in XMPP'
dependencies = {'xep_0030'}
stanza = stanza
default_config = {
'block_size': 1024 * 1024, # One MiB
'preferred': 'sha-256',
'enable_sha-1': False,
'enable_sha-256': True,
'enable_sha-512': True,
'enable_sha3-256': True,
'enable_sha3-512': True,
'enable_BLAKE2b256': True,
'enable_BLAKE2b512': True,
}
_hashlib_function = {
'sha-1': hashlib.sha1,
'sha-256': hashlib.sha256,
'sha-512': hashlib.sha512,
'sha3-256': hashlib.sha3_256,
'sha3-512': hashlib.sha3_512,
'BLAKE2b256': lambda: hashlib.blake2b(digest_size=32),
'BLAKE2b512': lambda: hashlib.blake2b(digest_size=64),
}
def __init__(self, *args, **kwargs):
super().__init__(*args, **kwargs)
self.enabled_hashes = []
def plugin_init(self):
namespace = 'urn:xmpp:hash-function-text-names:%s'
self.enabled_hashes.clear()
for algo in self._hashlib_function:
if getattr(self, 'enable_' + algo, False):
self.enabled_hashes.append(namespace % algo)
def session_bind(self, jid):
self.xmpp['xep_0030'].add_feature(Hash.namespace)
for namespace in self.enabled_hashes:
self.xmpp['xep_0030'].add_feature(namespace)
def plugin_end(self):
for namespace in self.enabled_hashes:
self.xmpp['xep_0030'].del_feature(feature=namespace)
self.enabled_hashes.clear()
self.xmpp['xep_0030'].del_feature(feature=Hash.namespace)
def compute_hash(self, filename, function=None):
if function is None:
function = self.preferred
h = self._hashlib_function[function]()
with open(filename, 'rb') as f:
while True:
block = f.read(self.block_size)
if not block:
break
h.update(block)
hash_elem = Hash()
hash_elem['algo'] = function
hash_elem['value'] = b64encode(h.digest())
return hash_elem
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