get device physical identity through web application
<p>For legal purposes, I need to find a way to obtain a "one-to-one" identity of a device that logs in to my web application.</p>

<p>Typically, Ill post a url through SMS or email and the end user opens the link in his/her default browser.</p>

<p>I know Phone number cant be retained consistently.
Also, I wouldn't get my hands into flash/active-X objects.</p>

<p>Are there any other ways?
Thanks.</p>