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Re: Open Source implementations Re: Encrypted Media proposal (was RE: ISSUE-179: av_param - Chairs Solicit Alternate Proposals or Counter-Proposals)

From: Charles Pritchard <chuck@jumis.com>
Date: Tue, 28 Feb 2012 10:40:43 -0800
Message-ID: <4F4D1FAB.10108@jumis.com>
To: Mark Watson <watsonm@netflix.com>
CC: Glenn Adams <glenn@skynav.com>, "Tab Atkins Jr." <jackalmage@gmail.com>, Kornel Lesiński <kornel@geekhood.net>, "<public-html@w3.org>" <public-html@w3.org>
On 2/28/2012 10:34 AM, Mark Watson wrote:
>
> On Feb 28, 2012, at 10:27 AM, Charles Pritchard wrote:
>
>> On 2/28/2012 9:07 AM, Glenn Adams wrote:
>>>
>>> 2012/2/28 Tab Atkins Jr. <jackalmage@gmail.com 
>>> <mailto:jackalmage@gmail.com>>
>>>
>>>     In your other case (server is untrusted), DRM is unnecessary
>>>     baggage;
>>>     you only need JS encryption/decryption that can be inserted between
>>>     the server and a <video> element of the user.  This can be specified
>>>     and implemented without many of the concerns that people have been
>>>     raising about this proposal.
>>>
>>>
>>> A solution that requires decryption of the actual media content in 
>>> JS would be unacceptable from a performance perspective, 
>>> particularly on resource constrained devices. The solution must be 
>>> readily implemented with reasonable performance on devices at 
>>> different ends of the spectrum, including TV/STBs (resource 
>>> constrained).
>>
>> Citation needed.
>
> Do you mean some evidence is needed for the requirement that the 
> solution work on constrained devices, or for the claim that JS 
> decryption would not be sufficiently performant on such devices ?
>
> ...Mark
>

Yes, I'm sorry that wasn't clear.

I see no reason why stream ciphers written in JS and using Typed Arrays 
could not meet performance requirements.

-Charles
Received on Tuesday, 28 February 2012 18:41:08 GMT

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