Film-Tech Forum ARCHIVE: KDM trouble: invalid signature

This is topic KDM trouble: invalid signature in forum Digital Cinema Forum at Film-Tech Forum ARCHIVE.

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Posted by Nader Ali (Member # 8013) on 10-01-2014, 05:48 AM:

I'm not even sure I know how to formulate my question, let alone understand any answers you guys might have - but I'll give it a go.

When loading the KDMs i get this message:
”Invalid signature – could not verify KDM signature”.

Usually I get only one kdm-file, but for this particular film (with only one screening) I got 2 zipped packages, each containing three files:

Package 1

cert_chain_Dolby256-CAT862-619620.pem.75848e20-2711-4abf-8121-787470219446.kdm

cert_Dolby256-CAT862-619620.der.crt.1fc08a43-02e8-4f46-9979-aa007b36044f.kdm

cert_Dolby256-CAT862-619620.pem.crt.e62609fa-bc51-4c7b-bc43-5abbd64fc813.kdm

Package 2

cert_chain_Dolby256-CAT862-619620.pem.3a03b91f-a5fd-4351-aa6f-c4c2bcb05f3e.kdm

cert_Dolby256-CAT862-619620.der.crt.dab05ff5-8d05-47c9-85ef-ba2469903afa.kdm

cert_Dolby256-CAT862-619620.pem.crt.b5a0bccf-8824-4a56-bc8a-b13db449c66c.kdm

Does anyone here know what might be the problem?

Here's a pic with one of the six error messages from the dolby server.

Thank you for your time,
Nader

Posted by Dave Macaulay (Member # 813) on 10-01-2014, 01:29 PM:

Whoever issued the KDM screwed up. I've seen similar problems when independent film producers bypass the major distributors here (who have pretty much figured out KDMs) and make their own DCPs and KDMs using Cineasset or something else. I believe the "signature" should be verified by a trusted issuer, you can "self sign" stuff but that's considered insecure.