Need help to Decrypt a m3u8 stream - encryption

Question

I recently found some m3u8 videos on a website and all of them are AES 128 encrypted.
Some parts of the links/codes are removed in order to reduce the lenght of the question.
I tried to download them by using following ffmpeg command.
ffmpeg -i 'https://example.com/vod/61e0c7b08a8fd.mp4/chunk.m3u8?nimblesessionid=4475264&wmsAuthSign=c2VydmVyX3RpbWU9MS8yMS=' -c copy output.ts
It gives out an error,
ffmpeg version 4.4-essentials_build-www.gyan.dev Copyright (c) 2000-2021 the FFmpeg developers
built with gcc 10.2.0 (Rev6, Built by MSYS2 project)
configuration: --enable-gpl --enable-version3 --enable-static --disable-w32threads
--disable-autodetect --enable-fontconfig --enable-iconv --enable-gnutls --enable-libxml2
--enable-gmp --enable-lzma --enable-zlib --enable-libsrt --enable-libssh --enable-libzmq
--enable-avisynth --enable-sdl2 --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxvid
--enable-libaom --enable-libopenjpeg --enable-libvpx --enable-libass --enable-libfreetype
--enable-libfribidi --enable-libvidstab --enable-libvmaf --enable-libzimg --enable-amf
--enable-cuda-llvm --enable-cuvid --enable-ffnvcodec --enable-nvdec --enable-nvenc --enable-d3d11va
--enable-dxva2 --enable-libmfx --enable-libgme --enable-libopenmpt --enable-libopencore-amrwb
--enable-libmp3lame --enable-libtheora --enable-libvo-amrwbenc --enable-libgsm --enable-libopencore-amrnb
--enable-libopus --enable-libspeex --enable-libvorbis --enable-librubberband
libavutil 56. 70.100 / 56. 70.100
libavcodec 58.134.100 / 58.134.100
libavformat 58. 76.100 / 58. 76.100
libavdevice 58. 13.100 / 58. 13.100
libavfilter 7.110.100 / 7.110.100
libswscale 5. 9.100 / 5. 9.100
libswresample 3. 9.100 / 3. 9.100
libpostproc 55. 9.100 / 55. 9.100
'https://example.com/vod/61e0c7b08a8fd.mp4/chunk.m3u8?nimblesessionid=4475264: Invalid argument
'wmsAuthSign' is not recognized as an internal or external command,
operable program or batch file.
Look like the link is not requested properly or something else.
Then I manually downloaded the chunk.m3u8 file and all the ts files specified in it.
Here is the content from the .m3u8 file,
#EXTM3U
#EXT-X-VERSION:3
#EXT-X-TARGETDURATION:10
#EXT-X-MEDIA-SEQUENCE:0
#EXT-X-KEY:METHOD=AES-128,URI="https://example/test.php?nimblesessionid=4356176&wmsAuthSign=c2VydmVyX3RpbWU9MS8yMS="
#EXTINF:10,
https://example.com:443/vod/61d23fc612669.mp4/n_0_0_0.ts?
nimblesessionid=4356176&wmsAuthSign=c2VydmVyX3RpbWU9MS8yMS=
#EXTINF:10,
https://example.com:443/vod/61d23fc612669.mp4/n_1_0_0.ts?
nimblesessionid=4356176&wmsAuthSign=c2VydmVyX3RpbWU9MS8yMS=
#EXTINF:10,
https://example.com:443/vod/61d23fc612669.mp4/n_2_0_0.ts?
nimblesessionid=4356176&wmsAuthSign=c2VydmVyX3RpbWU9MS8yMS=
#EXTINF:10,
https://example.com:443/vod/61d23fc612669.mp4/n_3_0_0.ts?
nimblesessionid=4356176&wmsAuthSign=c2VydmVyX3RpbWU9MS8yMS=
#EXTINF:10,
https://example.com:443/vod/61d23fc612669.mp4/n_4_0_0.ts?
nimblesessionid=4356176&wmsAuthSign=c2VydmVyX3RpbWU9MS8yMS=
#EXT-X-ENDLIST
But the key uri to decrypt the ts files doesn't work.
So I copied the key from the test.php file and made a new file and pasted it.
And then created a m3u8 playlist locally with all the file names and key file
specified in it as below,
#EXTM3U
#EXT-X-VERSION:3
#EXT-X-TARGETDURATION:10
#EXT-X-MEDIA-SEQUENCE:0
#EXT-X-KEY:METHOD=AES-128,URI=test.php
#EXTINF:10,
n_0_0_0.ts
#EXTINF:10,
n_1_0_0.ts
#EXTINF:10,
n_2_0_0.ts
#EXTINF:10,
n_3_0_0.ts
#EXTINF:10,
n_4_0_0.ts
#EXT-X-ENDLIST
and tried to decrypt it using following ffmpeg command,
ffmpeg -allowed_extensions ALL -i chunk.m3u8 -c copy -bsf:a aac_adtstoasc output.mp4
It gives out this error,
ffmpeg version 4.4-essentials_build-www.gyan.dev Copyright (c) 2000-2021 the FFmpeg developers
built with gcc 10.2.0 (Rev6, Built by MSYS2 project)
configuration: --enable-gpl --enable-version3 --enable-static --disable-w32threads --disable-autodetect
--enable-fontconfig --enable-iconv --enable-gnutls --enable-libxml2 --enable-gmp --enable-lzma
--enable-zlib --enable-libsrt --enable-libssh --enable-libzmq --enable-avisynth --enable-sdl2 --enable-libwebp
--enable-libx264 --enable-libx265 --enable-libxvid --enable-libaom --enable-libopenjpeg --enable-libvpx
--enable-libass --enable-libfreetype --enable-libfribidi --enable-libvidstab --enable-libvmaf --enable-libzimg
--enable-amf --enable-cuda-llvm --enable-cuvid --enable-ffnvcodec --enable-nvdec --enable-nvenc
--enable-d3d11va --enable-dxva2 --enable-libmfx --enable-libgme --enable-libopenmpt --enable-libopencore-amrwb
--enable-libmp3lame --enable-libtheora --enable-libvo-amrwbenc --enable-libgsm --enable-libopencore-amrnb --enable-libopus
--enable-libspeex --enable-libvorbis --enable-librubberband
libavutil 56. 70.100 / 56. 70.100
libavcodec 58.134.100 / 58.134.100
libavformat 58. 76.100 / 58. 76.100
libavdevice 58. 13.100 / 58. 13.100
libavfilter 7.110.100 / 7.110.100
libswscale 5. 9.100 / 5. 9.100
libswresample 3. 9.100 / 3. 9.100
libpostproc 55. 9.100 / 55. 9.100
[hls # 000001fb9011dac0] Skip ('#EXT-X-VERSION:3')
[hls # 000001fb9011dac0] Opening 'test.php' for reading
[hls # 000001fb9011dac0] Opening 'crypto:n_0_0_0.ts' for reading
[hls # 000001fb9011dac0] Opening 'crypto:n_1_0_0.ts' for reading
[hls # 000001fb9011dac0] Error when loading first segment 'n_0_0_0.ts'
chunk.m3u8: Invalid data found when processing input
So what I have done wrong in this attempt to download the m3u8 stream?
Can't figure out what to do next.There wasn't anyhting help full out there.
The browser is able to do all the stuff and decrypted the video.
So I know the video is decypted somewhere in the browser.
Then I opened the network tab in developer panel an checked for all the files recieved
by the browser carefully.Then I noticed that every time the first segment of the video(0_0_0_.ts)
is recieved by the browser,a new url is requested,
<blob:https://example.com/447bc693-052f-4bf0-b8e6-aca3b9f95e10>
And there is a big java script response in it and look like a some sort of
player or a decrypter(didn't include here).
Then I found this code in the inspect element,
<div class="relative h-0 overflow-hidden" style="padding-top: 60%;">
<div id="player" class="class-vc " style="position: absolute;top:0;height:100%;width:100%"
data-feedback-url="https://example.com/session-eyJpdiI6ImZaKz="
data-m-source="https://example.com/vod/61e7581a1143e.mp4/playlist.m3u8?wmsAuthSign=c2VydmVyX3RpbWU9MS8yMS=">...................
..........</div><video data-html5-video="" muted="true" preload="metadata" playsinline="playsinline"
src="blob:https://example.com/678d6566-d2bd-4af3-bef8-7e39fe265115"></video>
I don't have much knowledge about this.I couldn't find any helpful reference on this
and I think this has somethng to with this video.
Above is the procedure I followed to try to download the
hls stream and all of the problems I encountered while doing that.
Some parts of the links/codes are removed in order to reduce the lenght of the question.
So my question is, is there something I've missed here or anything I've done wrong.
I have no idea what to next.I guess that the blob player has something to do with this.
Any help would be greatly appreciated.