o-regan.org

Available from the download page.
Version 1.6

Fixed FileNotFound exception for xpi output file that doesn’t exist (yet). XPISigner now creates the file entry so the jar operation can use it.
Updated the unix script
Readme now correctly refers to the unix script as xpisigner.sh

When running XPISigner with a PFX generated from SPC & PVK files you may run into the following error…
“unwrapping private key - java.security.InvalidKeyException: Illegal key size”
This may have two causes:

The unlimited strength policy files are not installed in your %JAVA_HOME%/jre/lib/security folder.
The PFX that was generated is not well formed. See below for instructions on how to export [...]

I’ve been working on a firefox extension in my spare time, a little something that’s not quite ready for primetime yet. Having worked in the security industry for the last 7 years I was conscious that my extension probably wouldn’t be accepted by very many people if it wasn’t signed.[1] The closest thing to ‘official’ [...]

A random sampling of the extensions available on addons.mozilla.org shows that the majority of extensions available for download are unsigned. The only signed extension found in the search was the Google Toolbar.
The use of unsigned extensions encourages the end user to ignore the Unsigned warning in the corner.

(I’m not picking on Adblock specifically, it was [...]

XPISigner creates signed extensions or plug-ins for Firefox and Thunderbird.
It is a replacement for signtool.exe
Requirements:

Java 5 or higher
PKCS#12 (PFX) file containing your signing key and certificate
Your unpacked xpi directory structure

To sign the xpi file you need to point XPISigner at the directory containing your unpacked xpi.
XPISigner processes each file in the directory calculating the MD5 [...]

Let’s take a signed XPI apart and see what’re required to build a tool like XPISigner
We’ll use the Google Toolbar for Firefox as an example. It’s already signed and we can see it works when we download it.

Save off the xpi file from http://dl.google.com/firefox/google-toolbar.xpi