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‎README.md

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XMPP-OTR channel for Python
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===========================
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This is a Python library for communicating with XMPP destinations using OTR
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([Off-the-Record Messaging](https://otr.cypherpunks.ca/)) encryption.
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Features
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--------
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* Your internet application can talk securely to you on your PC or smartphone
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using readily-available chat software with OTR support
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* OTRv2
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* Send to and receive from multiple destinations, with or without fingerprint
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verification
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* Pure python (no libotr dependency)
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Example
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-------
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import time
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from otrxmppchannel import OTRXMPPChannel
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from otrxmppchannel.connection import OTR_TRUSTED, OTR_UNTRUSTED,
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OTR_UNENCRYPTED, OTR_UNKNOWN
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# Load the base64-encoded OTR DSA key. Constructing the object without
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# a key will generate one and provide it via ValueError exception.
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privkey = open('.otrprivkey', 'r').read()
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class MyOTRChannel(OTRXMPPChannel):
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def on_receive(self, message, from_jid, otr_state):
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if otr_state == OTR_TRUSTED:
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state = 'trusted'
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elif otr_state == OTR_UNTRUSTED:
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state = 'UNTRUSTED!'
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elif otr_state == OTR_UNENCRYPTED:
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state = 'UNENCRYPTED!'
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else:
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state = 'UNKNOWN OTR STATUS!'
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print('received %s from %s (%s)' % (message, from_jid, state))
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mychan = MyOTRXMPPChannel(
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'[email protected]/datadiode',
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'supersecret',
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[
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(
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'[email protected]',
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'33eb6b01c97ceba92bd6b5e3777189c43f8d6f03'
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),
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'[email protected]'
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],
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privkey
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)
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mychan.send('') # Force OTR setup
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time.sleep(3) # Wait a bit for OTR setup to complete
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mychan.send('This message should be encrypted')
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Notes
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-----
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* XMPP invitations are not handled
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* It seems to take roughly 3 seconds to set up an OTR session. Messages sent
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before the session is ready may be lost.
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* The private key serialization format is specific to pure-python-otr.
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Conversions from other formats are not handled.
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Dependencies
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------------
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* [xmpppy](http://xmpppy.sourceforge.net/) (>= 0.4.1)
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* [pure-python-otr](https://github.com/afflux/pure-python-otr) (>= 1.0.0)
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Author
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------
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* [Mike Gogulski](mailto:[email protected]) - <https://github.com/mikegogulski>
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Donations
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---------
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If you found this software useful and would like to encourage its
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maintenance and further development, please consider making a donation to
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the Bitcoin address `1MWFhwdFVEhB3X4eVsm9WxwvAhaxQqNbJh`.
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License
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-------
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This is free and unencumbered public domain software. For more information,
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see <http://unlicense.org/> or the accompanying UNLICENSE file.

‎UNLICENSE

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This is free and unencumbered software released into the public domain.
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Anyone is free to copy, modify, publish, use, compile, sell, or
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distribute this software, either in source code form or as a compiled
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binary, for any purpose, commercial or non-commercial, and by any
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means.
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In jurisdictions that recognize copyright laws, the author or authors
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of this software dedicate any and all copyright interest in the
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software to the public domain. We make this dedication for the benefit
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of the public at large and to the detriment of our heirs and
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successors. We intend this dedication to be an overt act of
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relinquishment in perpetuity of all present and future rights to this
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software under copyright law.
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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 NONINFRINGEMENT.
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IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR
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OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
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ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
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OTHER DEALINGS IN THE SOFTWARE.
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For more information, please refer to <http://unlicense.org/>

‎otrxmppchannel/__init__.py

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# -*- coding: utf-8 -*-
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from connection import Connection
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class OTRXMPPChannel(object):
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"""
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OTR-XMPP communications channel
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-------------------------------
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Uses Off-the-Record Messaging for communications with XMPP destinations
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See https://otr.cypherpunks.ca/
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Example::
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import time
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from otrxmppchannel import OTRXMPPChannel
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from otrxmppchannel.connection import OTR_TRUSTED, OTR_UNTRUSTED,
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OTR_UNENCRYPTED, OTR_UNKNOWN
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privkey = open('.otrprivkey', 'r').read()
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channel = OTRXMPPChannel(
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'[email protected]/datadiode',
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'supersecret',
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[
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(
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'[email protected]',
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'33eb6b01c97ceba92bd6b5e3777189c43f8d6f03'
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),
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'[email protected]'
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],
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privkey
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)
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def my_receive(msg, from_jid, otr_state):
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state = ''
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if otr_state == OTR_TRUSTED:
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state = 'trusted'
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elif otr_state == OTR_UNTRUSTED:
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state = 'UNTRUSTED!'
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elif otr_state == OTR_UNENCRYPTED:
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state = 'UNENCRYPTED!'
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else:
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state = 'UNKNOWN OTR STATUS!'
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print('received %s from %s (%s)' % (msg, from_jid, state))
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channel.send('') # set up OTR
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time.sleep(3)
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channel.send('This message should be encrypted')
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NOTE: XMPP invitations are not handled
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NOTE: It seems to take roughly 3 seconds to set up an OTR session.
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Messages sent before the session is ready may be lost.
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:param jid: source JID, e.g. '[email protected]'
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:param password: XMPP server password
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:param recipients: a single recipient JID, a tuple of
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*(jid, OTRFingerprint/None)*, or a list of same
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:param privkey: base64-encoded DSA private key for OTR. If *None* is
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passed, a new key will be generated and dumped via a *ValueError*
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exception.
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"""
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def __init__(self, jid, password, recipients, privkey=None):
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usage = 'recipients can be a single recipient JID, a tuple of ' \
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'(jid, OTRFingerprint|None), or a list of same. Example: ' \
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'[\'[email protected]\', ' \
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'(\'[email protected]\', ' \
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'\'43d36b01c67deba92bd6b5e3711189c43f8d6f04\')].'
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# normalize recipients to a list of tuples
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if isinstance(recipients, str):
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self.recipients = [(recipients, None)]
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elif isinstance(recipients, tuple):
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self.recipients = [recipients]
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elif isinstance(recipients, list):
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self.recipients = recipients
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else:
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raise TypeError(usage)
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for i in range(0, len(self.recipients) - 1):
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if isinstance(self.recipients[i], str):
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self.recipients[i] = self.recipients[i], None
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elif isinstance(self.recipients[i], tuple):
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if len(self.recipients[i]) > 2 or len(self.recipients[i]) < 1:
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raise TypeError(usage)
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if len(self.recipients[i]) == 1:
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self.recipients[i] = self.recipients[i], None
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else:
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raise TypeError(usage)
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self.connection = Connection(jid, password, privkey, self.on_receive)
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self.connection.start()
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def send(self, message):
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"""
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Send *message* to recipients
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:param message: message string
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"""
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for recipient in self.recipients:
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self.connection.send(message, recipient)
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def on_receive(self, message, from_jid, otr_state):
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"""
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Override this method to create a custom message receipt handler. The
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handler provided simply discards received messages. Here is an
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example::
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from connection import OTR_TRUSTED, OTR_UNTRUSTED, OTR_UNENCRYPTED
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if otr_state == OTR_TRUSTED:
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state = 'trusted'
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elif otr_state == OTR_UNTRUSTED:
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state = 'UNTRUSTED!'
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elif otr_state == OTR_UNENCRYPTED:
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state = 'UNENCRYPTED!'
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else:
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state = 'UNKNOWN OTR STATUS!'
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print('received %s from %s (%s)' % (message, from_jid, state))
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:param message: received message body
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:param from_jid: source JID of the message
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:param otr_state: an integer describing the state of the OTR
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relationship to the source JID (OTR_* constants defined in
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otrxmppchannel.connection)
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"""
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pass

‎otrxmppchannel/connection.py

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# -*- coding: utf-8 -*-
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import xmpp
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import threading
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import time
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from Queue import Queue
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import potr
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from otrmodule import OTRAccount, OTRManager
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OTR_TRUSTED = 0
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OTR_UNTRUSTED = 1
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OTR_UNENCRYPTED = 2
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OTR_UNKNOWN = 3
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def d(msg):
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print('---> %s' % msg)
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class AuthenticationError(Exception):
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pass
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class OTRXMPPMessage(object):
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def __init__(self, body, to_jid, fp=None):
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self.body = body
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self.to_jid = to_jid
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self.fp = fp
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class Connection(threading.Thread):
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def __init__(self, jid, password, pk, on_receive=None):
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threading.Thread.__init__(self)
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self.jid = xmpp.protocol.JID(jid)
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self.password = password
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self.on_receive = on_receive
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self.client = None
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self.q = Queue(maxsize=100)
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self.otr_account = OTRAccount(str(self.jid), pk)
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self.otr_manager = OTRManager(self.otr_account)
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def run(self):
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while True:
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while not self.client or not self.client.isConnected():
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cl = xmpp.Client(
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self.jid.getDomain(),
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debug=[]
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)
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conntype = cl.connect()
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if not conntype:
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d('XMPP connect failed, retrying in 5 seconds')
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time.sleep(5)
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continue
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self.client = cl
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self.client.UnregisterDisconnectHandler(
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self.client.DisconnectHandler)
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auth = self.client.auth(self.jid.getNode(), self.password,
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self.jid.getResource())
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if not auth:
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d('XMPP authentication failed')
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raise AuthenticationError
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self.client.sendInitPresence(requestRoster=0)
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self.client.RegisterDisconnectHandler(self._on_disconnect)
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self.client.RegisterHandler('message', self._on_receive)
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while self.client.isConnected() and self.client.Process(0.1):
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if not self.q.empty():
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self._send(self.q.get())
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pass
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def _on_disconnect(self):
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self.otr_manager.destroy_all_contexts()
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def _on_receive(self, _, stanza):
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fromjid = stanza.getFrom()
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body = str(stanza.getBody())
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# d('stanza from %s: %s' % (fromjid, body))
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if stanza.getBody() is None:
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return
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fromjid = xmpp.protocol.JID(fromjid)
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fromjid.setResource(None)
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otrctx = self.otr_manager.get_context(self.client, str(fromjid))
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encrypted = True
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res = ()
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try:
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res = otrctx.receiveMessage(body)
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except potr.context.UnencryptedMessage:
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encrypted = False
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except potr.context.NotEncryptedError:
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# potr auto-responds saying we didn't expect an encrypted message
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return
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msg = ''
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otr_state = OTR_UNKNOWN
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if not encrypted:
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if stanza['type'] in ('chat', 'normal'):
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msg = stanza.getBody()
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otr_state = OTR_UNENCRYPTED
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d('unencrypted message: %s' % msg)
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else:
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if res[0] is not None:
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msg = res[0]
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trust = otrctx.getCurrentTrust()
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if trust is None or trust == 'untrusted':
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otr_state = OTR_UNTRUSTED
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d('untrusted decrypted message: %s' % msg)
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else:
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otr_state = OTR_TRUSTED
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d('trusted decrypted message: %s' % msg)
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if msg is not None and msg != '':
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self.on_receive(msg, str(fromjid), otr_state)
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def _send(self, msg):
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# d('_send(%s, %s, %s)' % (msg.body, msg.to_jid, msg.fp))
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otrctx = self.otr_manager.get_context(self.client, msg.to_jid, msg.fp)
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if otrctx.state == potr.context.STATE_ENCRYPTED:
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if otrctx.getCurrentTrust() == 'untrusted':
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d('fingerprint changed from %s to %s for %s!' % (
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msg.fp, otrctx.fp, msg.to_jid))
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self.client.send(
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xmpp.protocol.Message(
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msg.to_jid,
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'I would like to tell you something, but I '
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'don\'t trust your OTR fingerprint.'))
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else:
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otrctx.sendMessage(0, str(msg.body))
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else:
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# d('Initializing OTR with %s (message "%s")' % (
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# msg.to_jid, msg.body))
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self.client.send(
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xmpp.protocol.Message(
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msg.to_jid,
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otrctx.account.getDefaultQueryMessage(otrctx.getPolicy),
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typ='chat'))
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def send(self, text, to_jid, fp=None):
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"""
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send a message to a JID, with an optional OTR fingerprint to verify
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:param text: message body
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:param to_jid: destination JID
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:param fp: expected OTR fingerprint from the destination JID
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:return:
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"""
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while self.q.full():
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d('queue full, discarding first entry')
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_ = self.q.get_nowait()
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if isinstance(to_jid, tuple):
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to_jid, fp = to_jid
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self.q.put_nowait(OTRXMPPMessage(text, to_jid, fp))

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