The solution outlined below is believed to be obsolete & ineffective, but retained for historical interest. Phorm have changed their method of operation to hi-jack image requests. You should encrypt your web communications using SSL.

Dephormation Cookie Rewriter

When a cookie is 'phorged' by Phorm, it may be possible to 'rewrite' it in your client side code.

Phorm will be unable to hide the rewritten cookie from your server. Your server side code will then be able to detect unexpected 'phorged' cookies.

This page demonstrates a client side script which creates a new cookie, by rewriting the cookies received from the server.

The rewritten cookies will be sent back to the server and dumped into this page (see below).

The Client Side Cookies

The Server Side Cookies

The cookies visible to the server are also shown in the green box below.

After refreshing this page, you should expect to see a cookie with the name Dephormation, and value 'Example Cookie'.

You should also see a 'rewritten' cookie with today's date as a name.