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» Film-Tech Forum   » Operations   » Digital Cinema Forum   » Erased the DCP O MATIC file, can I still make up a KDM?

   
Author Topic: Erased the DCP O MATIC file, can I still make up a KDM?
Cameron Glendinning
Jedi Master Film Handler

Posts: 844
From: West Ryde, Sydney, NSW Australia
Registered: Dec 2005


 - posted 10-11-2018 11:58 PM      Profile for Cameron Glendinning   Email Cameron Glendinning   Send New Private Message       Edit/Delete Post 
I just realized I have erased the DCP O MATIC programme file, I have kept the encryption code numbers involved as a text file. Is it somehow possible to make up a new KDM for the DCP that I have stored on a hard drive?

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Leo Enticknap
Film God

Posts: 7034
From: Loma Linda, CA
Registered: Jul 2000


 - posted 10-12-2018 11:22 AM      Profile for Leo Enticknap   Author's Homepage   Email Leo Enticknap   Send New Private Message       Edit/Delete Post 
quote: DCP-o-Matic Manual
You must be careful when using encryption not to lose important keys.

If you are making KDMs from a DCP-o-matic film you must ensure that you have a backup of the metadata.xml file from the project, as well as the DCP itself.

If you are using a DKDM you must ensure that you have a backup of DCP-o-matic's config.xml file, since it contains the only key which can decrypt the DKDM. The config.xml file location depends on your operating system; possible locations are listed in Chapter 18, Configuration files


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Ioannis Syrogiannis
Expert Film Handler

Posts: 104
From: Athens, Hellas (Greece)
Registered: Jun 2005


 - posted 10-12-2018 11:28 AM      Profile for Ioannis Syrogiannis   Email Ioannis Syrogiannis   Send New Private Message       Edit/Delete Post 
Wouldn't that have a faster answer in the DCP-o-matic forum?

You can head to dcpomatic.com and click on help, then follow the forum link. For some reason, the forum link is not on the first page...

P.S. Leo gave a full response while I was searching the way to not use a link...

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Cameron Glendinning
Jedi Master Film Handler

Posts: 844
From: West Ryde, Sydney, NSW Australia
Registered: Dec 2005


 - posted 10-12-2018 04:03 PM      Profile for Cameron Glendinning   Email Cameron Glendinning   Send New Private Message       Edit/Delete Post 
Thank you for the reply's, I kinda knew I was wishful thinking when I posted but it was worth asking
.

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Carl Hetherington
Film Handler

Posts: 88
From: York, North Yorkshire, England
Registered: Jul 2012


 - posted 10-12-2018 04:12 PM      Profile for Carl Hetherington   Author's Homepage   Email Carl Hetherington   Send New Private Message       Edit/Delete Post 
As others have said, the DCP-o-matic forum would probably get you a quicker answer!

What do you mean by "encryption code numbers"? You might be able to make a KDM with them, depending on what they are...

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Carsten Kurz
Film God

Posts: 3774
From: Cologne, NRW, Germany
Registered: Aug 2009


 - posted 10-12-2018 05:58 PM      Profile for Carsten Kurz   Email Carsten Kurz   Send New Private Message       Edit/Delete Post 
Cameron - you may have erased your DCP-o-matic installation, but your config file including the certs is probably still there. Do you still have the project directory where the encrypted DCP was created?

- Carsten

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Randy Stankey
Film God

Posts: 6425
From: Erie, Pennsylvania
Registered: Jun 99


 - posted 10-12-2018 05:58 PM      Profile for Randy Stankey   Email Randy Stankey   Send New Private Message       Edit/Delete Post 
What, exactly, did you delete?

If you simply deleted the application file but not the prefs/settings folder(s) then you should be able to find those folders, temporarily rename them, reinstall the application then move the original files back to their rightful place and you should be okay.

Think of what you would have to do when you want to reinstall an application like Firefox without losing all your bookmarks, passwords and settings. The process would be similar.

However, if you deleted everything, including your prefs folder, you will have a tougher problem to solve. You’ll have to recover all your encryption keys and reinstall them before you can encrypt files or play back encrypted files.

If you can’t recover your keys, you’re basically hosed.

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Cameron Glendinning
Jedi Master Film Handler

Posts: 844
From: West Ryde, Sydney, NSW Australia
Registered: Dec 2005


 - posted 10-14-2018 04:06 PM      Profile for Cameron Glendinning   Email Cameron Glendinning   Send New Private Message       Edit/Delete Post 
Hi all

I have only created one file that needed a KDM, I still have DCP O Matic as working software on my computer. I kept the file that actually ingests and plays in the projector but erased the rest of the files for that project.

I did keep a text file of the actual code used for the encryption which I suspect is worthless.

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Carl Hetherington
Film Handler

Posts: 88
From: York, North Yorkshire, England
Registered: Jul 2012


 - posted 10-14-2018 05:50 PM      Profile for Carl Hetherington   Author's Homepage   Email Carl Hetherington   Send New Private Message       Edit/Delete Post 
What do you mean by "actual code used for the encryption"? The 32-digit code from the metadata.xml?

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Carsten Kurz
Film God

Posts: 3774
From: Cologne, NRW, Germany
Registered: Aug 2009


 - posted 10-15-2018 03:51 AM      Profile for Carsten Kurz   Email Carsten Kurz   Send New Private Message       Edit/Delete Post 
I guess he wrote down the encryption data string that he either input or had generated manually under the DCP tab (and that went to the - lost - metadata file). So, technically, he has everything he needs to decrypt that DCP, but which tools will allow him to create a KDM from that?

asdcplib will allow to decrypt the assets using the raw key, but that process is a bit cumbersome.

Can he create a fake metafile for an encrypted DCP and edit that key into it? Then how can he assign the CPL/UUID of the existing DCP in order to see it as target for KDM creation?

- Carsten

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