How can I get a host computer unique ID in PHP?
<p>I need to come up with a way to uniquely identify computers. 
Something like the system id or info from CPU that can't be hacked easily
be obtained in php application run time and then sent over the internet to a central database to activate or validate license keys. </p>

<p>System Info:</p>

<ul>
<li>Web Shared Hosting or Local network</li>
<li>Linux(can be any  distribution)</li>
<li>Apache</li>
<li>PHP</li>
</ul>

<p>Thanks in advance for any reply</p>
