There are many chat apps that support OTR encryption for verifying messages. Many of us use multiple chat apps, including one for desktop and another for mobile, or one for Mac OS X and another for GNU/Linux or Windows. The trust relationships are only stored locally in the app in a format that is specific to that app. Switching between all of them means that you have to manage your trust relationships for each app that you use.
KeySync addresses this problem by allowing you to sync your OTR identity and trust relationships between multiple apps, which eliminates the need to re-establish those relationships on each new client/device. It currently works with ChatSecure on Android, and Pidgin, Adium, and Jitsi on desktop.
Please note: KeySync does not make it easier to have simultaneous encrypted chats with the same account logged into multiple clients or devices. There are limitations in the OTR protocol that make this impossible.
To sync between ChatSecure and your desktop apps, plug in your phone or device
via USB and run the sync. Or you can manually copy the otr_keystore.ofcaes
file over to your device's SD Card, where ChatSecure looks for it. Using
ChatSecure, you will need to scan the QRCode that KeySync shows you in order
to complete the sync. The otr_keystore.ofcaes file is encrypted to prevent
your private information from leaking out. That QRCode is the password to
your keystore, so do not share it with anyone.
If you have multiple chat apps that you use, or you are switching from one to another, you can use KeySync to sync up the trust relationships between multiple desktop apps. Here's how:
- quit all of the chat apps that you want to
- select whichever apps you want to sync
- then run the sync
Now, open your chat apps and you should have synced trust! In case of problems, it saved your original OTR files in place. They are named using a long string of numbers that represent the time when they were backed up.
This is beta software, do not rely on it for strong identity verification. It
is unlikely to mess up so bad as to produce compromised private keys, but
anything is possible. Also, keep in mind that program is handling your
private OTR keys, so make sure that you don't copy, send or email the
otr_keystore.ofcaes file somewhere unsafe. All that said, testing
and feedback is greatly appreciated, so we can get it to the point where we
can trust it.
This project has libraries for converting the various OTR file formats between each other. We have focused on the two major versions: libotr format and otr4j, and then a few variants of those major formats. All OTR implementations can be supported as long as they can be read and parsed by Python.
KeySync has preliminary support for Gajim and IRSSI, and it has a modular architecture to allow for expansion. If you want to add an app that is not already included, you just need to make a single python file that converts between that app's OTR data format and the KeySync internal format (documented below).
We appreciate all feedback, be it bug reports, patches, pull requests, feature requests, etc. Please add your bugs and requests to our issue tracker:
https://dev.guardianproject.info/projects/keysync/issues
Email us at [email protected] with questions, problems, etc., or just to let us know that you are using KeySync and find it useful.
KeySync uses lots of Python modules to achieve a smooth syncing
experience. To see a complete list of python modules used on your
platform, see the dependencies list in setup.py. Here are some of
the key libraries:
- BeautifulSoup 4 - http://www.crummy.com/software/BeautifulSoup
- psutil - https://code.google.com/p/psutil
- pure-python-otr - https://github.com/afflux/pure-python-otr
- pyasn1 - http://pyasn1.sourceforge.net/
- pycrypto - https://www.dlitz.net/software/pycrypto
- pyjavaproperties - http://pypi.python.org/pypi/pyjavaproperties
- pymtp - https://github.com/eighthave/pymtp
- pyparsing - http://pyparsing.wikispaces.com
- python-pgpdump - https://pypi.python.org/pypi/pgpdump
- Python Imaging Library - http://www.pythonware.com/products/pil
- qrcode - https://github.com/lincolnloop/python-qrcode
- Tkinter - https://wiki.python.org/moin/TkInter
We're working to get all packages into official Debian/Ubuntu/etc. releases, in the meantime you can install KeySync by adding our PPA (fingerprint F50EADDD2234F563):
sudo add-apt-repository ppa:guardianproject/ppa
sudo apt-get update
sudo apt-get install keysync
PPA URL: https://launchpad.net/~guardianproject/+archive/ppa
If you want to install the dependencies because you're going to develop KeySync, then install them manually with:
sudo apt-get install python-pyparsing python-pyasn1 python-potr python-pymtp \
python-pyjavaproperties python-beautifulsoup python-qrcode libmtp-dev \
python-pgpdump python-crypto python-psutil python-tk python-imaging-tk
For Debian, you can try using the Ubuntu PPA, with something like oneiric for wheezy, and natty for squeeze:
deb http://ppa.launchpad.net/guardianproject/ppa/ubuntu oneiric main
For Mac OS X, you can download the binary app from our website: https://guardianproject.info
You use Brew, Fink, or MacPorts to install pip and virtualenv, then use those tools to install KeySync (see the pip+virtualenv install section):
fink install pip-systempython26 virtualenv-systempython26
sudo port install py27-pip py27-virtualenv
For homebrew, see: https://gist.github.com/pithyless/1208841
Once you have pip and virtualenv, then you can start to build the whole thing. First follow the pip+virtualenv instructions below. Then come back here and do the following in your virtualenv:
rm -rf build dist
pip install py2app
python setup.py py2app
ls dist/
If you are using py2app older than 0.7.4 on Mac OS X 10.6, then you need to patch py2app to make it work with python2.6:
pip install --upgrade py2app
patch env/lib/python2.6/site-packages/py2app/build_app.py py2app-python2.6.patch
For Windows, you can download the binary app from our website: https://guardianproject.info
Build instructions for Windows are in win32/README.md in the source folder.
Install these build dependencies locally, then follow the instructions for pip+virtualenv below:
sudo yum install gmp-devel tk tkinter python-pillow python-pillow-tk
Activate your virtual python environment then run pip to install the dependencies:
virtualenv ./env
. env/bin/activate
pip install -e .
./keysync
For a nice step-by-step HOWTO, see: http://exyr.org/2011/virtualenv-HOWTO/slides.html
Note: Doesn't work on Windows! See win32/README.md
Currently, the code allows for reading multiple file formats into a python
dictionary form. The only export method currently activated is for ChatSecure
format in a file called otr_keystore.ofcaes. To use, point the keysync
script the app that you want to read OTR info from, and it will generate
otr_keystore to send to ChatSecure on your Android device (run
keysync --help to see all currently available options).
keysync --input pidgin
Adium: ~/Library/Application Support/Adium 2.0/Users/Default/otr.private_key ~/Library/Application Support/Adium 2.0/Users/Default/otr.fingerprints ~/Library/Application Support/Adium 2.0/Users/Default/Accounts.plist
Uses the standard libotr files and overall file format for otr.private_key and otr.fingerprints. Account ID is stored as an integer which must be referenced from the Accounts.plist to get the actuall XMPP account name (e.g. [email protected]). Uses full word descriptive tags for the various protocols, e.g. libpurple-oscar-AIM, libpurple-Jabber, etc.
Pidgin GNU/Linux ~/.purple/otr.private_key ~/.purple/otr.fingerprints Windows %APPDATA%.purple\otr.private_key %APPDATA%.purple\otr.fingerprints
Uses the standard libotr files and overall file format for otr.private_key and otr.fingerprints. Account IDs are used directly in the libotr files. XMPP/Jabber Account IDs include the "Resource" e.g. [email protected]/Resource or [email protected]/Pidgin.
irssi ~/.irssi/otr/otr.key ~/.irssi/otr/otr.fp
Uses the standard libotr file format and files, but names the files differently, basically abbreviated versions of the libotr names. Account IDs are used directly in the libotr files.
xchat ~/.xchat2/otr/otr.key ~/.xchat2/otr/otr.fp
Same as irssi
ChatSecure: /data/data/info.guardianproject.otr.app.im/files/otr_keystore
All OTR information is stored in a single Java .properties file. Private keys, public key fingerprints, and verification status are each individual properties. This format also includes the storage of the remote public keys, unlike libotr. otr4j implementations load the remote public key from the store rather than always getting it from the OTR session.
Jitsi: GNU/Linux ~/.jitsi/sip-communicator.properties ~/.jitsi/contactlist.xml Mac OS X ~/Library/Application Support/Jitsi/sip-communicator.properties ~/Library/Application Support/Jitsi/contactlist.xml Windows ~/Application Data/Jitsi/sip-communicator.properties ~/Application Data/Jitsi/contactlist.xml
All app settings are stored in a single Java .properties file, including OTR information. Private keys, public key fingerprints, and verification status are each individual properties.
pure-python-otr is pure python implementation of the OTR spec. It includes newer features like Socialist Millionaire's Protocol. The private key is stored in a separate file per-account. The fingerprints are stored in the same tab-separated-value format as libotr but with a fingerprint file per-account.
Gajim: GNU/Linux: ~/.local/share/gajim/SERVERNAME.key3 ~/.local/share/gajim/SERVERNAME.fpr ~/.config/gajim/config Windows: ~/Application Data/Gajim/
The private key is serialized in a custom format: p, q, g, y, x, written consecutively to a file as MPIs. See potr/compatcrypto/pycrypto.py.
KeyCzar stores keys in JSON files with two different formats: 0.5b and 0.6b. It uses a special base64 encoding with a URL-safe alphabet:
- replaces + _ replaces /
http://code.google.com/p/keyczar/wiki/DsaPrivateKey http://code.google.com/p/keyczar/wiki/DsaPublicKey
0.6b public: "q": The DSA subprime "p": The DSA prime "g": The DSA base "y": The DSA public key exponent "size" : The size of the modulus in bits private: "publicKey": The JSON representation of the corresponding DsaPublicKey "x": The secret exponent of this private key "size" : The size of the modulus in bits
0.5b public: "x509": A WebSafeBase64 encoded X509 representation private: "pkcs8": A WebSafeBase64 encoded PKCS#8 representation of the private key "publicKey": A WebSafeBase64 encoding of the key's corresponding DsaPublicKey
A ZID record stores (caches) ZID (ZRTP ID) specific data that helps ZRTP to achives its key continuity feature. Please refer to the ZRTP specification to get detailed information about the ZID.
ZRTP key types: 2048 bit Diffie-Helman values 3072 bit Diffie-Helman values 256 bit Diffie-Helman elliptic curve 384 bit Diffie-Helman elliptic curve
Here are some notes on how things are implemented in KeySync.
The key idea in the implementation is to get everything into a common format internally. That common format can then be handed to any class for a given program, which knows how to output it to the correct file format. The current internal data format is a dict of dicts representing a key, called 'keydict'. So first, you have a dict representing a given account with a given key associated with it. This account name is used as the unique ID. Then the whole collection of keys, both local private keys and remote public keys, are collected in meta dict with the account name as the key and the whole dict as the value. This format allows for easy merging, which enables syncing between files.
Sample structure in python dict notation:
keydict = {
'userid': {
'fingerprint': 'ff66e8c909c4deb51cbd4a02b9e6af4d6af215f8',
'name': 'userid',
'protocol': 'IRC',
'resource': 'laptop', # the XMPP "resource"
'verification': 'verified', # or 'smp' for Socialist Millionares
'p': '<p value>', # public part of the DSA key
'q': '<q value>', # public part of the DSA key
'g': '<g value>', # public part of the DSA key
'x': '<x value>', # core of private DSA key
'y': '<y value>', # core of public DSA key
},
'userid2' : { ... },
...
'useridn' : { ... }
}
Unfortunately each app has its own string IDs to represent the different IM protocols. KeySync uses the Pidgin IDs internally. KeySync is currently focused on the widely deployed common standards of XMPP and IRC. We welcome contributions for working with the other protocols. These are the IDs that are currently working throughout:
prpl-bonjour XMPP Bonjour (serverless XMPP with mDNS discovery) prpl-irc IRC (Internet Relay Chat) prpl-jabber XMPP (Jabber)
Here is the full list of IDs from Pidgin: https://developer.pidgin.im/wiki/prpl_id
