Could not decrypt kdm

Anything and everything to do with DCP-o-matic.
nikola1
Posts: 6
Joined: Mon Aug 21, 2023 11:29 am

Could not decrypt kdm

Post by nikola1 »

Hi All, I need to open an encrypted DCP in order to burn in Czech subtitles and the distributor agreed that they will make a DKDM so I can open the DCP in my dcp-o-matic. I send them a certificate that I exported from my dcp-o-matic and they send me a DKDM back, howewer, it doesn´t load it. Instead it says " Could not decrypt KDM (error:02000072:rsa routines::padding check failed) (256/2048)" I am not an expert, I am just trying to help out this little festival (I am a projectionist) and I don´t know if there is something I did wrong or the lab that send me that key. They say the DKDM is correct.. Anybody has encountered a similar issue? Thanks a lot for any possible advise!

Nikola
Carsten
Posts: 2804
Joined: Tue Apr 15, 2014 9:11 pm
Location: Germany

Re: Could not decrypt kdm

Post by Carsten »

Maybe you can send the certificate you sent them, and their DKDM, to carl via email.


Which version of DCP-o-matic do you use?
nikola1
Posts: 6
Joined: Mon Aug 21, 2023 11:29 am

Re: Could not decrypt kdm

Post by nikola1 »

Hi Carsten, thanks for a quick reply, I am using the 2.16.50 version on Win10. In the meantime I am also trying to create my own encrypted dcp with dkdm to learn more about encryption, as you suggested in another thread...

I opened the DKDM in notepad and it shows that it was created in EASYDCP , but that shouldn´t be a problem, right?
Last edited by nikola1 on Mon Aug 21, 2023 1:41 pm, edited 1 time in total.
Carsten
Posts: 2804
Joined: Tue Apr 15, 2014 9:11 pm
Location: Germany

Re: Could not decrypt kdm

Post by Carsten »

You could post the DKDM here. Without access to your private key, it is useless for anyone else. Padding check failed may suggest a simple formal issue with the DKDM, but it could also be a bug.
nikola1
Posts: 6
Joined: Mon Aug 21, 2023 11:29 am

Re: Could not decrypt kdm

Post by nikola1 »

Here´s the DKDM
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carl
Site Admin
Posts: 2548
Joined: Thu Nov 14, 2013 2:53 pm

Re: Could not decrypt kdm

Post by carl »

Can you also attach the certificate that you sent to them?
nikola1
Posts: 6
Joined: Mon Aug 21, 2023 11:29 am

Re: Could not decrypt kdm

Post by nikola1 »

This is the certificate exported from my dcpomatic. I didn´t upgrade or changed anything after exporting it.
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carl
Site Admin
Posts: 2548
Joined: Thu Nov 14, 2013 2:53 pm

Re: Could not decrypt kdm

Post by carl »

It looks like the KDM has been made for the wrong certificate. The certificate's dnQualifier is

Code: Select all

g6tMT7e+eKlxzTPF9xqRqUI9l10=
but the KDM's recipient is

Code: Select all

KoeBY/pyD8s\+gNx6iGbGRAHUJis=,
. Maybe you could double-check with them that they are using the right certificate.
nikola1
Posts: 6
Joined: Mon Aug 21, 2023 11:29 am

Re: Could not decrypt kdm

Post by nikola1 »

Thank you so much, I will check with them!
RAY-NUE
Posts: 111
Joined: Mon Aug 21, 2023 4:18 am
Location: Ratchaburi, Thailand

Re: Could not decrypt kdm

Post by RAY-NUE »

nikola1 wrote: Mon Aug 21, 2023 1:43 pm Here´s the DKDM
<ContentKeysNotValidBefore>2023-10-18T17:49:48+00:00</ContentKeysNotValidBefore>

<ContentKeysNotValidAfter>2024-10-24T17:49:48+00:00</ContentKeysNotValidAfter>

movie theater to use Is it in this time zone?