So it read the last 48bytes Then do a 0x2E xor on it.
hxxps://i.ibb.co/bWtK403/ecrypt-decrypt.jpg
Note that the user_id and the video_id is embedded within the file (also stored at the end of the file)
So here is the data structure starting from the end:
48bytes xored with 0x2E corresponding to the header of the file.
8 null bytes(delimiter?)
UnknowInt32
8 null bytes(delimiter?)
UnknowInt32
UnknowInt32
8 null bytes(delimiter?)
UnknowInt32
video_id (int32)
user_id (int32)
EOF (for the video file)
x bytes[FileContent]
48bytes[] that needs to be replaced by the end bytes xored for the moment they seem to be useless.
So by applying that I was able to retrieve your mp4 files which are from https://fr.tuto.com/after-effects/gratuit-initiation-complete-d-after-effects-after-effects,49795.html (I didn't remove your user_id/video_id)
https://www.sendspace.com/filegroup/RMqSpPbmzMobgzR7U5kRGg
Btw you can get your user_id, just connect to tuto.com, inspect the src code and at the bottom, there is your user_id
Next step create a python script to automate this, but should be trivial will probably have more time next weekend
Enjoy
BTW hxxps://www.relyze.com/beta3.html is amazing and free for non-commercial project