High-bandwidth Digital Content
Protection (HDCP)
Along with the introduction of
DVI technology came the need to
prevent the digital video data
from being pirated, or copied
without authorization. In order
to address this issue
High-bandwidth Digital Content
Protection (HDCP) was derived.
HDCP, developed by the
Intel Corporation,
implements a key encryption
encoded into the DVI signal
which, without the proper HDCP
decoding mechanism, produces
either extremely low resolutions
or static. To avoid this, both
source and display devices must
have DVI connections that
support software key HDCP
decoding.
HDCP, also used by the new
HDMI technology, was
strongly endorsed by the
entertainment industry, for
obvious reasons. What makes
this technique of key encryption
possible is its renewability.
The
Digital Content Protection LLC,
an organization responsible for
licensing of the HDCP
technology, monitors the secret
keys used to encrypt the data.
If at any time they believe a
set of secret keys has been
compromised by an unauthorized
source, those keys are placed on
a revocation list and new keys
are provided to devices
authorized by license.
HDCP also uses a method of
authentication to ensure that
the receiving device is licensed
to receive HDCP encrypted data.
This authentication process
repeats itself every few seconds
in order to be certain that an
illegal device has not been
connected after the initial
authentication. If and when
this authentication fails, the
source device will immediately
end all encrypted transmissions.