From: smb@research.att.com
Date: Tue, 15 Feb 94 08:18:28 PST
To: hughes@ah.com (Eric Hughes)
Subject: Re: Clipper and Traffic Analysis
Message-ID: <9402151609.AA13123@toad.com>
MIME-Version: 1.0
Content-Type: text/plain


	 >Does anyone here have any thoughts as to whether Clipper enables traf
	fic
	 >analysis or tracing more easy than it normally is under Switching Sys
	tem
	 >7? 

	 SS7 uses out-of-band signalling.  The clipper LEAF is an in-band
	 signal.  Therefore a tap for clipper yields two kinds of information,
	 content and identities.

	 Tapping an SS7 signalling network is more expensive and more difficult
	 to justify.  More expensive because it runs packet-switched, more
	 difficult because it's not the conversation of any particular party
	 except the phone company.

Also, it probably goes via a different physical path.  And at least some
SS7 trunks are encrypted with DES.