Another ECMS question

Hi there!

Just another ECMS question:

One problem of ECMS is that once a copy of a work has been sold and distributed over a network this copy could be used to make subsequent copies without any payments.

What are the possibilities to prevent this?

You can use digital watermarks, of course, but that only helps to identify the original from which the subsequent copies have been made, it doesn't prevent subsequent copies. Also encryption doesn't help because once it's decrypted you can distribute this copy just as you want; and so on...

What projects/techniques are used to prevent those subsequent copies (just like SCMS for DAT consumer tapes, e.g.)?

Any hints would be greatly appreciated...

Stefan

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+++++ Stefan Bechtold  ++++ stefan.bechtold[_at_]jura.uni-tuebingen.de +++++
++++++ http://www.jura.uni-tuebingen.de/student/stefan.bechtold/ ++++++
+++ Ist nicht Elektren hier, damit auch sie mit uns zugrunde gehe ? +++