Cryptochat

Webbasierter Chat mit clientseitiger Verschlüsselung.

http://cryptochat.de

Achtung in Entwicklung befindliche BETA Software

Cryptochat basiert auf [cryptocat] (https://crypto.cat) und ermöglicht dir spontanes verschlüsseltes chatten ohne Einrichtung oder Installation. Es ist Open Source Software, und eine sichere Alternative zu Chatdiensten wie Google-Talk oder Facebook-Chat.

Cool features

• A client-side 4096-bit Diffie-Hellman-Merkle public key agreement engine.
• A client-side AES-256 implementation is used to encrypt data.
• HMAC message integrity verification.
• The identity of chatters can be confirmed via key fingerprints, à la OTR.
• Uses the Fortuna secure pseudo-randomness generator.
• Send encrypted .zip files and images.
• Includes a mobile website compatible with iPhone, Android and BlackBerry.
• Cryptocat Chrome, a Chrome app that loads all code locally, and is secure from being served compromised code.
• Chats are securely deleted after one hour of inactivity.
• Easily invite your Facebook contacts to join your Cryptochat session.
• Send private messages that can only be seen by a single recipient.
• A sleek design with time-stamping, optional audio notifications, fluid-window mode, and mobile support.
• Translations available for French, Catalan, Basque, Italian, German, Portuguese, Russian and Swedish.

Protocol Specification

A design specification for the Cryptochat protocol is available.

License

Cryptochat is released under the Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License:

• Noncommercial — You may not use this work for commercial purposes.
• Attribution — You must attribute the work to the Cryptochat project (but not in any way that suggests that they endorse you or your use of the work).
• Share Alike — If you alter, transform, or build upon this work, you may distribute the resulting work only under the same or similar license to this one.

Additionally: 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.

Installation instructions

1. Run ./make.sh inside the js/src/ directory in order to generate the client-side cryptography code (requires gcc.)
2. Configure settings inside index.php.

Important notes

• Cryptochat provides strongly encrypted, secure communications. However, it is not a replacement to GPG. Think responsibly if you are in extreme, life-threatening situations.

• Using Cryptochat without HTTPS in a production environment is a recipe for disaster. We severely warn against deploying Cryptochat without HTTPS, unless the deployment is occurring as a Tor Hidden Service.

• Paranoid users may want to use Cryptochat Chrome, a Chrome app that loads all code locally, and is secure from being served compromised code.

• The code for secure deletion of idle chats after one hour is not included in the Cryptochat git repository. On the production server, it's actually a cron job that checks the modification time of chats and wipes them securely. Those wanting to set up similar functionality should consider writing something similar.

• If Cryptochat does not work on your server, please make sure PHP is compiled with shmop support (--enable-shmop).

About

Cryptocat™ is a trademark of and is developed by Nadim Kobeissi. It uses parts of the crypto-js library and the Bitcons iconset. Cryptocat is indebted to Paul Brodeur, David Mirza, Hasan Saleh, Morgan Sutherland, and Tina Salameh.