Encrypt This! - Firefox extension

Some History
Public Key Encryption
Generating Keys
My Public Key
Passphrase Encryption
Version control
Contact me

Important Update

I am currently unable to get this to work reliably on Firefox 3. It works for some people and not for others and appears to have something to do with how FF was upgraded.
Unfortunately I don't seem to be able to overcome this right now. If anybody is able to help out and get this working again I would be most appreciative.

Some History

This extension evolved from the Greasemonkey script which does similar encryption. Please check out the original script for more background on the javascript behind this extension. The main reasons for turning the script into an extension were;

If you are in a hurry then you can just go ahead and install this extension right now;

Install Now

Naturally you will need firefox to run this.

In addition to the public key style encryption offered with the greasemonkey script, this extension also allows passphrase encryption as this was a regularly featured request. The advantage of using the passphrase is that it is easier to send the email to a group of people and it is obviously easier to remember the secret bits. On the other hand the public key system is great for sending emails between individuals without having to come up with a method of exchanging keys in a secure manner first.

After installing the extension (and restarting Firefox) an additional item will be added to the Tools menu and the right click menu. Right click anywhere or select some text and then right click to start the process.

Public key type encryption

This is ideal for exchanging emails with people without having to meet or devise another secure strategy to exchange keys before the time.

Generating Keys

Before sending or receiving encrypted emails, you will need to create public and private keys. Key Generation is available here as well. Note that when using the script you will need to use the full key generated. E.g. paste or type pub:101:11 or priv:123:9 into the appropriate input boxes.

My public key

pub:2219717:17 (See notes above on entering the keys in the input boxes.)

Below is an example showing a new public key being added in the preferences section

Here the key is being selected by the user. Only the name has to be remembered now and the public key will be automatically entered in the public key area. This is only advisable for people that you wish to send to on a regular basis. For one-off situations it is better to simply paste the public key into the area provided.

Passphrase type encryption

This method is really useful when sending emails to a group of people as it would be a very tedious operation to encode and send each email individually with every person's public key. The drawbacks, however, are as follows;


There are a number of preferences that can be adjusted. Most of the changes will require the main window containing the encryption area to be closed down and restarted for them to have effect.


The image below shows the public key encryption in action. Notice the public key which was entered automatically.

The image to the right shows the passphrase encryption in action. The passphrase itself is clearly visible as I figured it would be too risky turning it into a "password style" entry field. If enough users want this changed then I could do so.


In addition to the scripts used in the original Greasemonkey script, I also used the work done by John Walker on the passphrase encryption.

Version control

0.1.42008/06/21Firefox 3 compatibility
0.1.32007/02/03Fixed AES variable declaration issue with Firefox 2.0
0.1.22006/10/06Fixed help link
0.1.12006/09/21Initial Version


Suggestions? Improvements?
mailencrypt at langenhoven.com