Windows CardSpace provides the ability for websites to request identity information. The support for using it is built into Internet Explorer. CardSpace is one of the elements of the .Net Framework 3.0, which Microsoft introduced alongside Windows Vista and has back-ported to Windows XP and Windows Server 2003.

One of the most common questions asked about CardSpace is "does Firefox support CardSpace" (or vice-versa). Until now, the answer has been "not yet". But now a new plug-in providing Firefox support for Microsoft's CardSpace digital-identity framework is available for public download.

Solution architect Kevin Miller, who played an instrumental role in developing the technology, announced the availability of his Firefox add-on for Windows via his blog. This is a fabulous step forward on the path of taking CardSpace mainstream and all of you Firefox fans out there should download and install the Firefox extension.

Here a list with the features that this extension has by now:

- Support for both the <object> and <ic:informationcard> syntax.

- Support for both JavaScript invocation (using xmlToken.value) and <form> posting (both implicit and using form.submit() ).

- Supports object parameters required for the selector . These are scriptable, and most are read/write. I've tried to validate these as much as possible. I'm sure testing will turn up cases I've missed, so I expect this code will need to be updated as items are found. See more details in my post containing samples.

- This should support all certificates that Firefox supports.

- Pluggable identity selector. The extension creates an XPCOM Interface for Identity Selectors, of which I’ve implemented one that calls Windows CardSpace, and the end user can switch between them (right now, you have to change a pref in about:config , but I’ll add in an options dialog soon).

- Error objects should be identical to the IE implementation (for ease of cross-platform web development)

- Uninstalls!

written by Robert M.