On June 13, 2010 at 15:19, Brentm said...
If what you are asking is...
Does the source, AVR &/or other inline device in any way change the actual video data (other than to overlay OSD) that is on the disc (or other media) to provide a measure of security?
No, nothing changes the data as it is written.
OK. So, my uneasiness comes from reading material from DCP that seems to state otherwise. The material seems to state that the TMDS stream is bit for bit encrypted using the keys of the transmitter and receiver. And, that in the link between AVR and display, the AVR would be considred the transmitter. Might I be misreading this material? Of course!
I hope I don't offend trying to reconcile the apparent difference between these two trusted sources of info (i.e. you and DCP.) Perhaps you could have a peak and reconcile this apparent difference. The first of the following links does not specify that the encryption is on the TMDS line, but the second one does:
[Link: digital-cp.com]Page 5
After authentication, the transmitter uses its HDCP cipher engine and the shared session key to create a stream of encrypted data that can only be decrypted by the receiver. The receiver uses its HDCP cipher engine and its copy of the session key to decrypt the content.
[Link: digital-cp.com]Page 35
HDCP Encryption is applied at the input to the T.M.D.S. Encoder and decryption is applied at the out of the T.M.D.S. Decoder (Figure 3-1).
Why?
And how does this effect what you do on the job?
Because, if the HDCP content sent between the source and the AVR is encrypted using one set of keys (i.e. that of the source and AVR), and then that HDCP content is sent from the AVR to the display using a different set of keys (i.e. that of the AVR and display), then the two streams are not the same set of bits. This means that the AVR is sending a new stream (i.e. and not just repeating an existing stream.) That means it is reconstuting any parsable signal.
BTW: I think that Bob L is referring to all of the batch header info (such as Clock, Row, Column, pixil number etc) which is digital by nature.
That has nothing to do with content protection.
What is sent is what is received (not accounting for line loss).
OK, let's see if this is what Bob L means? Or, if he means that the content is in fact encrypted?
The HD Fury should be a good indicator about this.
It spoofs HDCP and does a video Digital to Analog down conversion and Viola!
From what I understand, it doesn't just spoof the HDCP - it uses illegally obtained keys that have not been revoked to perform the authentication and decryption.
Here's one account of this from an old thread (see second paragraph of lined post):
[Link: curtpalme.com]
Last edited by crosen on June 13, 2010 16:03.
