My solution to this also addresses the scaling issue, something we are
going to have to face up to in the next few years. Distributed caching
helps to avoid network bottlenecks as people try to down load documents
from key servers. For copyrighted material, this means you have also need
to distribute the security mechanisms that ensure only "licensed" users
can get access to the material as intended by the publisher.
So one approach is to allow unlimted distributed caching of encrypted
copyrighted material, and for publishers to use trusted "book shops" to
handle the end-user access mechanism. In otherwords, an end-user can
pay a bookshop for per-use or unlimited use of some book or magazine.
The bookshop is instructed by the publisher as to what licence schemes
are acceptable, and pays the publisher in the traditional manner. The
distributed cache acts as an analog of the traditional distribution
channel, but in this case, the book shop can get copies immediately rather
than having to wait days or weeks for the next shipment.
As for the encryption mechanism, publishers could use DES or similar and use
public key technology to authenticate book shops and pass them the DES key
and sales policy info. End users can still cache documents for which they
have paid, and in the long term we still would benefit from hardware based
security mechanisms to enforce licence terms at the client's site. The above
scheme is relatively easy to implement using Secure HTTP. Scaling and
copyright concerns will soon give birth to the tiered distribution channels
on the Internet that are so familiar to us in the everyday world.
-- Best wishes,Dave Raggett
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