# DRM with a CDN

**URL:** <https://community.wowza.com/t/drm-with-a-cdn/37664>\
**Category:** Wowza Streaming Engine\
**Created:** [January 31, 2012, 4:46pm UTC](https://community.wowza.com/t/drm-with-a-cdn/37664 "2012-01-31T16:46:48Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![Nick\_Doyle](https://avatars.discourse-cdn.com/v4/letter/n/9fc348/32.png) [@Nick\_Doyle](https://community.wowza.com/u/Nick_Doyle)\
**Post date:** [January 31, 2012, 4:46pm UTC](https://community.wowza.com/t/drm-with-a-cdn/37664/1 "2012-01-31T16:46:48Z")

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I’m wondering - in a “per-user” on-the-fly encryption scenario, would there be no use in edges caching the encrypted fragments; they’re not going to be useful to any users except the one intended recipient right? Am I missing something here, are there some other recommended practices?

Cheers

Nick

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**Author:** ![Charlie\_Good](https://sea2.discourse-cdn.com/flex002/user_avatar/community.wowza.com/charlie_good/32/383_2.png) [@Charlie\_Good](https://community.wowza.com/u/Charlie_Good)\
**Post date:** [January 31, 2012, 4:13am UTC](https://community.wowza.com/t/drm-with-a-cdn/37664/2 "2012-01-31T04:13:36Z")

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If you are doing unique keys per-session then you are correct. Caching will have no benefit. If you are doing per-file, per-stream encryption then caching will be effective.

Charlie

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**Author:** ![Richard\_Lanham](https://avatars.discourse-cdn.com/v4/letter/r/c68b51/32.png) [@Richard\_Lanham](https://community.wowza.com/u/Richard_Lanham)\
**Post date:** [July 18, 2013, 8:29pm UTC](https://community.wowza.com/t/drm-with-a-cdn/37664/3 "2013-07-18T20:29:35Z")

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Larc,

There is nothing built-in to Wowza that will help. If the data is in a structured file or database you should be able to write a script to create it.

Richard

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**Author:** ![Lionel\_Gattegno1](https://avatars.discourse-cdn.com/v4/letter/l/3bc359/32.png) [@Lionel\_Gattegno1](https://community.wowza.com/u/Lionel_Gattegno1)\
**Post date:** [July 18, 2013, 4:42pm UTC](https://community.wowza.com/t/drm-with-a-cdn/37664/4 "2013-07-18T16:42:46Z")

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Hi,

how to set up a per-file encryption with BuyDRM AddOn?

We have a 10,000+ video library so it’s a little hard to create buydrmstreammap.txt file containing all the keys…

Thanks for our help.

Regards,

Larc

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**Author:** ![Lionel\_Gattegno1](https://avatars.discourse-cdn.com/v4/letter/l/3bc359/32.png) [@Lionel\_Gattegno1](https://community.wowza.com/u/Lionel_Gattegno1)\
**Post date:** [August 23, 2013, 1:01pm UTC](https://community.wowza.com/t/drm-with-a-cdn/37664/5 "2013-08-23T13:01:47Z")

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OK thanks,

I created my own class implementing IBuyDRMStreamNameToKeyInfo to do the job, works perfectly !

Larc