Clipper and Traffic Analysis
Does anyone here have any thoughts as to whether Clipper enables traffic analysis or tracing more easy than it normally is under Switching System 7? The reason I ask is, I have this sense that one reason the government likes Clipper is that the Law Enforcement Access Field enables agents to draw inferences about who's talking to whom and what they're saying, even without decrypting the actual communications. What do you think? --Mike
-----BEGIN PGP SIGNED MESSAGE----- Mike Godwin asks whether one of Clipper's attractive points (well, not to us, anyway) is the increased ability of LE to do traffic analysis.
The reason I ask is, I have this sense that one reason the government likes Clipper is that the Law Enforcement Access Field enables agents to draw inferences about who's talking to whom and what they're saying, even without decrypting the actual communications.
Of course! Let's say that you call someone who's under Clipper surveillance. Of course, you use your Clipperphone(*). The feds can now go to a judge and say "Well, we know the holder of this key ID called the suspect we have under surveillance... we want to surveil _his_ line too." Guilt by association. The agents should ideally have lawful authorization to be monitoring the line, but think how easy it would be to do full-time, real-time traffic analysis based on LEAF information. - -Paul (*) Not meant to imply that Mike would be likely to use a Clipperphone. - -- Paul Robichaux, KD4JZG | PGP key via finger & keyservers. perobich@ingr.com | Be a cryptography user- ask me how. Intergraph Federal Systems | Of course I don't speak for Intergraph. -----BEGIN PGP SIGNATURE----- Version: 2.3a iQCVAgUBLWD0FiA78To+806NAQF8KgP+PNlaWhQeBKXZuMLnvAqX0PaPwpnY+R6g 3g1snyCjLNxOGYlCOO0y/NczPsSxyp0yMMvod/XWrVCZutx/aKaepzq6AXA4o8qh e0OnpgEKwkyfK49qTx5As7ajdRcDMIGSmiUvrKKodEZZhSB2+V3hKfN8Hdgq0A6b aDIUhxHPXFs= =1qsj -----END PGP SIGNATURE-----
Does anyone here have any thoughts as to whether Clipper enables traffic analysis or tracing more easy than it normally is under Switching System 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. Eric
Please pardon my error. I referred in my initial post in this thread to "Switching System 7." Of course, I meant to say "Signaling System 7." I knew I should have had some coffee this morning. --Mike
Mike Godwin says:
Does anyone here have any thoughts as to whether Clipper enables traffic analysis or tracing more easy than it normally is under Switching System 7? The reason I ask is, I have this sense that one reason the government likes Clipper is that the Law Enforcement Access Field enables agents to draw inferences about who's talking to whom and what they're saying, even without decrypting the actual communications.
What do you think?
Normally, one can only determine the endpoints of a conversation. With clipper, however, one can deduce a lot more, since when people move around, go to hotels, phone booths, etc, you can still track their clipper serial numbers. Perry
participants (4)
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hughes＠ah.com -
Mike Godwin -
paul＠poboy.b17c.ingr.com -
Perry E. Metzger