[FFmpeg-devel] ASF file decryption

Vladimir Pantelic pan
Mon Apr 7 17:55:23 CEST 2008

Ruchika Chaddha wrote:
> Hi,
>  I have to decrypt a DRMed ASF file (.wma), I want to know which portion of
> ASF file is protected? Is it the entire data object (excluding data object
> header)?  I have the keys to decrypt but don't know where to start
> decrypting data from. Also, is the whole content decrypted with same
> symmetric key?
>  Your reply would be highly appreciated,

First of all this is the wrong list, this is not related to ffmpeg development!

Then, for ASF every audio and video payload (=frame) is encrypted on it's own.
Yes, it is most likely a fixed key, but there is some IV magic to be done per

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