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Windows 7: How to restore WMC digital cable DRM after reinstalling Windows?

16 Apr 2013   #1

Windows 7 Pro 64-bit
How to restore WMC digital cable DRM after reinstalling Windows?

My SSD died recently taking Windows with it. I managed to save my data, but the Windows installation is trashed. Now I find that after reinstalling Windows 7 on the exact same hardware (minus the hard drive) I can no longer access any of my recorded digital cable TV files. I've tried everything I can think of - copying over the Windows activation tokens, all the eHome and DRM folders, but Media Center still won't play the files because it thinks they came from a different PC.

The suggestions on Microsoft's site don't help - they assume that the DRM keys can be reacquired from a central source, but as far as I can tell there is no central source for digital cable DRM. It's all built into the client when the CableCard and PlayReady are set up. Help please?

My System SpecsSystem Spec

19 Apr 2013   #2

Windows 7 Pro 64-bit

Well, it appears that the keys are tied to a number of files in C:\Windows\System32\spp\tokens\channels\OCUR and C:\Windows\System32\spp\tokens\ppdlic. I tried replacing them with the old versions but they were overwritten with the new ones again. It didn't stick even when when I copied them outside Windows. This suggests to me that 1) there's a watchdog service monitoring these files and 2) the real keys are elsewhere, and these files are the output rather than the source.
My System SpecsSystem Spec
26 Apr 2013   #3

Windows 7 Pro x64 (1), Win7 Pro X64 / WinXP Pro x86 on (2)

If the original recordings were from programs provided by your cable service as "copy once" then it appears in your recordings list with info that shows "copy protected".

This type of WTV content cannot be played back on anything except the very original machine hardware and installed Windows 7 OS that did the original recording. This is not a matter of copying a file from your old system to your newly reinstalled system... the encryption/decryption keys are based on actual hardware/software information that cannot be hacked or overcome in any way known to man.

If you've reinstalled Windows 7, and if these are copy-protected "copy once" programs, you will never ever be able to view them again.

Now if you have a "system image" backup of your old installed Windows 7 system, you can restore it to what hopefully is still your original (or primarily original) hardware, and you WILL be able to play those recordings which were made using the original Windows 7 reflected in that "system image". But a reinstalled Windows 7? Done. You're doomed. You will NOT be able to play those old recordings.

Just to give a little more understanding of the depth of the DRM encrypt/decrypt key mechanism built into Windows 7, if you do restore a "system image" from say a week ago, but you'd made some copy-protected recordings in the past week, you will be able to play copy-protected recordings made prior to the date of the "system image" you just restored. But you will NOT be able to play any of the copy-protected recordings made in the last week, i.e. newer than the date of the "system image" you reverted to with your restore.

The reason for this is the time-based nature of the encryption key built into DRM, and implicit in the date/time of the "system image" backup. The key present in that "system image" is only good to decrypt recordings made prior to that backup's date/time. It cannot be used successfully to decrypt any newer recordings even though it is still the same machine hardware and effectively the identical original installed OS. But the date/time nature of the encryption key used when recordings are made makes it unusable to decrypt any copy-protected recordings made after its implicit date/time. Very sophisticated encryption method.

Sorry... there is no workaround.
My System SpecsSystem Spec

27 Apr 2013   #4

Windows 7 Pro 64-bit

Well that sucks. I find it more than a little strange and irritating that Windows activation can be restored with only two files, but Media Center is an absolute mess. Even when it works it's a pain. Ah well. Thanks for the reply. I don't suppose you know of any good non-Media Center recording software for cablecards?
My System SpecsSystem Spec
27 Apr 2013   #5

Windows 7 Pro x64 (1), Win7 Pro X64 / WinXP Pro x86 on (2)

Quote   Quote: Originally Posted by Mogster View Post
I don't suppose you know of any good non-Media Center recording software for cablecards?
None exist other than Windows Media Center and Microsoft. That's who made the deal with Cablelabs to allow them to record copy-protected content through cablecard-enabled tuners like Ceton (internal or external USB), or SilconDust HD Homerun Prime (network based tuners). It really was Cablelabs and their "suits" who laid down the rules, and Microsoft had to agree, so blame Cablelabs not Microsoft.

These cablecard tuners wouldn't exist if Microsoft hadn't agreed to this bullet-proof DRM scheme to absolutely prevent 100% digitally bit-for-bit perfect copies of copy-protected content which gave birth to the hardware manufacturers who provide what WMC then runs on. Then blame your cable company (e,g, TWC) for copy-protecting pretty much EVERYTHING THEY CARRY, including basic cable channels, not just the premium channels.
My System SpecsSystem Spec

 How to restore WMC digital cable DRM after reinstalling Windows?

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