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Amit Chandel
Guest
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 Posted:
Sat Sep 18, 2004 12:27 am Post subject:
Change KeyID and Seed (reHeader) |
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Is is possible to change KeyID, Seed when streaming the download using
the reHeader object ? From preliminary tests I've noticed it
scrambles the video if the KeyID <> the original header KeyID.
Is there another way to slap on an entirely new header (without having
to save to disk).
Also why are we forced to use a pre-DRM'd source when using reHeader,
it would be so much easier if we could have a RAW wmv, and protect it
on the fly.
Thanks,
Amit Chandel.
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Amit Chandel
Guest
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| Posted:
Sat Sep 18, 2004 12:45 pm Post subject:
Re: Change KeyID and Seed (reHeader) |
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Scrib,
Ok it makes sense, the wmv data packets are encoded with the KeyID +
Seed so naturally, the header Key would have to stay the same.
In this model, every customer that downloads video.wmv will have the
same
KeyID and Seed. That is nice, but it bothers me security wise, that
we are in essence issuing the same KEY per Content that is the same
for everyone. If we were able to change the KeyIDs and generate a
different key, now everyone has a different key, even for the same
content.
The key was to take advantage of reHeader. We can make a script to
re-encode but we are dealing with 700MB wmv's, and saving to disk will
just tax the hardware and create all sorts of limitations.
Is there a way to re-encode, and use the reHeader to distribute on the
fly ?
Thanks,
Amit Chandel
| Quote: | The encryption key used to actually encrypt the contents
is generated using the key id and seed. So if you change
these it isn't going to work. (If you randomly hack teeth
off your house key it won't work either, same principal),
it was locked using those items, you can't change it.
If you want to use Raw wmv and encrypt on the fly, why not
make a script that encrypts the raw wmv file using the
Rights Manager encoding routines prior to download? |
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scrib
Guest
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| Posted:
Sun Sep 19, 2004 2:55 am Post subject:
Re: Change KeyID and Seed (reHeader) |
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Yup, you're out of look on trying to issue one new key for
already encoded content.
Exactly what are your worries security-wise as long as
you're using Individualization?
Movielink, CinemaNow, Napster, Musicmatch, and a ton of
other huge corporations seem happy with the security, and
ever since the patch fro FreeMe came out 3 years ago the
DRM security hasn't been compromised.
If you're looking for a higher standard of security than
that you may be getting a little too picky.
As long as each piece of content has a different key
you've maxed out your security. To unlock your content a
brute force attack would have to be done on each piece.
If the Microsoft DRM is cracked period. it won't matter
how many keys you have either, it will all be wide open
anyhow.
So basically my recomendation is not to worry, if MS-drm
gets cracked you're screwed regardless, but for now your
security is fine.
| Quote: | -----Original Message-----
Scrib,
Ok it makes sense, the wmv data packets are encoded with
the KeyID +
Seed so naturally, the header Key would have to stay the
same.
In this model, every customer that downloads video.wmv
will have the
same
KeyID and Seed. That is nice, but it bothers me security
wise, that
we are in essence issuing the same KEY per Content that
is the same
for everyone. If we were able to change the KeyIDs and
generate a
different key, now everyone has a different key, even for
the same
content.
The key was to take advantage of reHeader. We can make a
script to
re-encode but we are dealing with 700MB wmv's, and saving
to disk will
just tax the hardware and create all sorts of limitations.
Is there a way to re-encode, and use the reHeader to
distribute on the
fly ?
Thanks,
Amit Chandel
The encryption key used to actually encrypt the
contents
is generated using the key id and seed. So if you
change
these it isn't going to work. (If you randomly hack
teeth
off your house key it won't work either, same
principal),
it was locked using those items, you can't change it.
If you want to use Raw wmv and encrypt on the fly, why
not
make a script that encrypts the raw wmv file using the
Rights Manager encoding routines prior to download?
.
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