SECURITY Secure Instant Messaging

From Gentoo Linux Wiki

[edit] in progress

This work is still in progress, yet is mostly functional.

[edit] Secure Messaging

This page describes an example setup for secure messaging with jabber, gnupg and jap.

[edit] PSI, A Jabber client

psi PSI is probably the best Jabber client that supports GPG encryption.

[edit] Emerge PSI

Emerge it with cryptography and ssl enabled.

echo "net-im/psi crypt ssl" >> /etc/portage/package.use
emerge psi

[edit] Start PSI and create a new account

Start PSI

psi

1. In order to create a profile, click the "Profile" button.
2. Choose "new" to create a new profile. Enter a name for your profile and click the "Create" button.
3. Press "Open"
4. Enter your account name and check "Register new account".
5. Your are free to choose your name (unless it is already in use). Here is a list of public servers
6. Click "Add".

[edit] GnuPG, The GNU Privacy Guard

GnuPG homepage

[edit] Emerge GnuPG

Emerge GnuPG

emerge gnupg

[edit] Create a key-pair

creating a key

gpg --gen-key
*Please select what kind of key you want:
(1) DSA and ElGamal (default)
*What keysize do you want? (1024)
1024 (or more)
*Please specify how long the key should be valid.
0 = key does not expire
*Is this correct (y/n)?
y (if it is correct for you)
*Real name:
paranoid123
*Email address:
paranoid123@jabber.com
*Comment:
the paranoid
*Change (N)ame, (C)omment, (E)mail or (O)kay/(Q)uit?
O (if okay)
*You need a Passphrase to protect your secret key.
*******(more length = more secure)
*We need to generate a lot of random bytes.....
move your mouse and/or type something

public and secret key created and signed.
key marked as ultimately trusted.
pub  1024D/'''C863E51B''' 2004-04-29 paranoid123 (the paranoid) <paranoid123@jabber.com>
Key fingerprint = E556 C3DF 75B5 A246 75A6  971C 9F74 C645 C863 E51B
sub  1024g/7EE57E15 2004-04-29

There is a 8-digit hexadecimal number marked in bold. This is your so called key-id for your public key.

[edit] Propagate your public key

Upload your public key to a keyserver.

gpg  --keyserver wwwkeys.de.pgp.net --send-key paranoid123@jabber.com

[edit] Encrypted Messaging

[edit] your secret key in psi

1. Restart PSI. Choose "Account Setup" from the bottom left menu.
2. Click "Modify".
3. Click "Select Key" and choose your public key from the list.
4. Though it is a security issue, you may want to check "Save Passphrase" and enter your passphrase. Click "Save"

[edit] Add a contact

You will need the contacts jabber address and public key-id (e.g. 0x1234ABCD.)

[edit] Receive public key from keyserver

$ gpg  --keyserver wwwkeys.de.pgp.net --recv-key 0x1234ABCD

The public-key will be added to your pgp-key-ring. You have to restart PSI.

[edit] Add contact to psi

Choose "Add Contact" from the PSI menu. Enter the "Jabber ID" and the optional "Nickname". Click "Add"