it is unlikely that network administrators would try to sniff packets as it would be much easier to simply check the files posted on a public share
in some cases such as a personal web page the public share is on a network server while in other cases such as in a P2P network the shared directory is on a client computer
on a network server it is easy for the network operator to scan the files on the public directory for copyright material.
on a P2P net all the files would have to be downloaded, — or — better — a crawler would be used
anyway you cut the cake they will put a stop to all this copyright violation activity the question in the air is how much collateral damage will occur
Unbreakable DVD encryption technology took three months before it was universally defeated, Microsoft’s DRM technology lasted 22 days, the Apple iPhone’s security measures were broken in about a month and a half. TIVO’s was smashed in six hours. SecureRun game protection lasted for 14 days.
At any one moment, there are probably a 4 trillion files available through the typical P2P network. About half of them are in the clear, the other half are wrapped in compression technology. To do what you suggest, network engineers would have to develop matching ‘digital fingerprints’ for known copyrighted works, and compare those digital fingerprints to files available in the public share.
When their first or second enforcement action is done, those digital fingerprints become meaningless as the slightest change to the data changes the digital fingerprint - if they’re going after 192k CBR mp3 files, change it to a VBR file, and it’s a completely different fingerprint, digitally considerably different than the originating piece of work.
Even shifting a couple bits in the header of the digital file, or changing the ID3 text embedded in the mp3 file, renders previous investigative work meaningless. Sure, the human ear can tell it’s a song by a well known artist, but to the digital eyes scanning the data, it’s nothing like what they’re looking for.