HLS Stream : Encrypted TS

[Pozz]

Hi everybody,

I'm trying to download a video from a website wich uses hls stream protocol. I managed to get the playlist file and all the ts files, but when I try to concatenate them with ffmpeg, it doesn't works obviously.
In the playlist file, there a URI link to the key:

#EXT-X-KEY:METHOD=AES-128,URI="link to the key",IV=0x3838c5776a2114c7233d9099fb7d7bf2

There's a python script on the forum (Here) but when I execute it, it says to me this error:

AttributeError: 'M3U8' object has no attribute 'key'

The key given by the website is a 16 bytes incomprehensible word :

D×><
AiB?a±?U<Á

If you want more information about the website, send me a pm, I'm trying not to get the attention from them.
Thanks!