Local ECM simulcrypt.
Publication Date: 2002-Feb-14
The IP.com Prior Art Database
Local ECM simulcrypt
Content received in a home network needs to be protected according to DRM rules.
One could use the proprietary CA system which was used for distribution of the content to the
home network. A more useful alternative is to provide a local "baseline" CA system, which is
less complex and full-featured and typically only provides protection against unauthorized
copying. ECMs in the content then need to be converted to the rules of the baseline system,
but now information in the original ECM that cannot be represented in the baseline ECM is
To overcome this problem, a copy of the original proprietary ECM is also provided
with the content after the conversion. It could be inserted in the stream, or provided
separately. The original ECM could also be maintained as-is in the stream. A receiving
apparatus that supports the proprietary CA rules can make use of this information, and other
devices can use the baseline ECM. The proprietary ECM could for instance be used in
advanced business models like pay-per-view that are not supported by the baseline system.
In an embodiment the "Simulcrypteur" equipment as known from US-B1-6,307,939 is
used to add a baseline ECM to the content stream. In the terminology of this patent, the SYSB
ECM comprises the baseline CA information, and the SYSA ECM the proprietary, fullfeatured
CA information. The Simulcrypteur, installed in the gateway, converts (a copy of)
the S YSA ECM to the local rules and thereby produces the SYSB...