Please use the git head master branch of libotr which contains a critical fix for irssi-otr to work. (Fix commit: d748757e581b74e7298df155ad49174cb914102b)

http://sourceforge.net/p/otr/libotr/ci/master/tree/

LibOTR (http://www.cypherpunks.ca/otr/) support for IRSSI.

Mailing list: otr-dev@lists.cypherpunks.ca

First of all, we strongly recommend to set this option to speed up any OTR commands or sessions.

/set cmd_queue_speed 1msec

The default value of irssi is much higher and used to avoid excess flood on IRC servers. However, with the message size this module is using and rate of a normal conversation, it seems OK to set this limit. Please inform us if it causes problems.

Future works is to handle IRC excess flood inside this module.

• libotr 4.0.x - Download Link

• irssi-dev >= 0.8.15 - Download Link

• glib2.0 Development package

• libgcrypt >= 1.5.0

• automake, autoconf, libtool

Run the following commands to compile and install.

$ ./bootstrap

$ ./configure --prefix="/usr"

$ make && make install

1. /load otr in the Irssi main window.
2. Open a chat window with your buddy.
3. /otr init, initiate OTR session.

If no key is found for your user and server, the key generation will be launched.

You should see OTR: Gone secure and you are ready to communicate over OTR.

To load the OTR module at startup, use the following and make sure otr.so is located in the modules/ directory of the Irssi home (usually ~/.irssi).

echo "load otr" >> ~/.irssi/startup

Once loaded, we recommend you add the OTR status bar allowing you to see the OTR state of private conversation.

/statusbar window add otr

Possible states are:

• Plaintext
• Finished
• OTR
• OTR (unverified)

Key generation happens in a separate process and its duration mainly depends on the available entropy. If no key is detected for the current user and server, the keys will be generated automatically for you. Or else, you can run:

/otr genkey nickname@server-addr-fqdn

Once done, you should see a message in the irssi main window indicating completion.

OTR: Key generation for <nickname> completed in X seconds. Reloading keys.

The default OTR policy irssi-otr is now something between manual and opportunistic. Manual means you have to start it yourself by issuing a /otr init command and opportunistic means both peers send some magic whitespaces and start OTR once they receive these whitespaces from the other side.

Irssi-otr uses a mode in between where we are not sending whitespaces as an announcement (as in opportunistic) but we still handle whitespaces if we see it from the other side. Therefore if your peer uses opportunistic the handshake should still start automatically once he writes something.

To display the fingerprint of the OTR key you just generated, one can type /otr info to show the fingerprint.

In order to be sure you are communicating with the right person you can do two things to autenticate him or her.

1. Use a shared secret previously decided between both parties or exchanged, ideally in person. Use the following command to iniate or respond to an authentication request.

   /otr auth SHARED_SECRET

2. The second method is to use the socialist millionaire problem (SMP) mechanism which consist of asking the other party a question for which him or her will only be able to respond with the correct answer.

   /otr authq [YOUR QUESTION HERE] SHARED_SECRET

   And respond with the command on number 1 above.

3. The third way is to trust manually. Exchange your fingerprint with the other party over a telephone or GPG-signed email for instance.

   /otr trust [FP]

   You can either type this command in the private conversation window of the buddy fingerprint you want to trust or enter the FP argument which is the five parts of the human readable fingerprint available via the /otr contexts command.

   For example: /otr trust 487FFADA 5073FEDD C5AB5C14 5BB6C1FF 6D40D48A

You can abort an ongoing authentication at any time by using this command.

/otr authabort

To distrust a fingerprint for whatever reason you may have, use the following command which is like the trust command above.

/otr distrust [FP]

To completely forget a fingerprint meaning it will be erased from the OTR fingerprints file. Again, same as trust/distrust command, you can either enter the five parts of the fingerprint or execute the command in the private conversation window.

/otr forget [FP]

If the window is closed, a finish action is triggered informing the other hand that you have ended the private session. The status bar will indicate plaintext if so.

You can also use the /otr finish command to end the OTR session without closing the window.

If your buddy finishes the session, you will be notified and the status bar will indicate finished in yellow.

• Print the irssi-otr module version.

/otr version

• List all OTR contexts and their status.

/otr contexts

In /otr/otr.{key,fp} you'll find the fingerprints and your private keys (should you at any point be interested). There is also the otr.instag file which is of no importance for you and used by libotr.