Milk is a Chrome extension designed to limit cross-site tracking without reducing functionality for the user.
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We created Milk to illustrate the concept of functional privacy. Milk is designed to limit cross-site tracking without reducing functionality for the user. The general idea is to restrict, or bind, cookies to the first-party site from which they were created rather than disabling cookies entirely.

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#Algorithm Overview

Milk implements cookie binding by intercepting cookies both before they are stored and before they are sent. Imagine this simplified example using a single first-party site. When the user visits, the server responds with an HTTP Set-Cookie header instructing the browser to store a cookie. Milk will rewrite the cookie before it is stored, appending the key "!!!" to the cookie’s name. For subsequent web requests to, Milk will rewrite the HTTP Cookie header to both remove the domain-specific keys and ensure that only cookies with the appropriate key are sent back to the server.

See for more information.

#Loading the Extension (from source)

Load the extension by clicking (Wrench)->Tools->Extensions to bring up the extensions window. Make sure the "Developer mode" box is checked. Click the "Load unpacked extension" button and navigate to the directory holding the extension source.

#Before first use

For best results, make sure to remove all existing cookies. You can do this by selecting (Wretch) -> History -> Clear all browsing data... -> Check the box for "Delete cookies and other site and plug-in data" -> Clear browsing data.

#View the console

On the Extensions tab, select the arrow to the left of the extensions name to view additional information and options. Click the link "_generated_background_page.html".


Copyright (C) 2012 Robert Walls and Shane Clark

This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program. If not, see