Universal HLS Decryptor & Downloader Autor: Ömer Bilal Yay

Universal HLS Decryptor & Downloader

A powerful Firefox extension that fully automates the downloading and decryption of AES-128 encrypted HLS (HTTP Live Streaming) video streams (.m3u8). It perfectly handles complex streaming platforms that utilize dynamic key rotation.
🔑 Segment-Level Encryption & Key Rotation

The core challenge this extension solves is dynamic key rotation mid-stream.

Segment-Level Encryption: Each #EXT-X-KEY tag applies to all subsequent #EXTINF segments until a new #EXT-X-KEY tag is encountered.


Example M3U8:

EXTM3U

EXT-X-KEY:METHOD=AES-128,URI="https://example.com/key.php?id=1"

EXTINF:10.0,

https://example.com/segment1.ts

EXTINF:10.0,

https://example.com/segment2.ts

EXT-X-KEY:METHOD=AES-128,URI="https://example.com/key.php?id=2"

EXTINF:10.0,

https://example.com/segment3.ts

(In this example, Key 1 decrypts segments 1 and 2. Key 2 decrypts segment 3.)
🛡️ Multi-Layer Key Extraction

To combat DRM and obfuscation, the extension guarantees key acquisition using three fallback strategies:

Direct URI Fetch: Scrapes auth tokens from local storage and fetches keys directly via HTTP.
Network Sniper: Intercepts live network traffic to extract raw AES bytes on the fly.
Crypto Hooking: Injects a CSP-bypassing script to monkey-patch crypto.subtle.importKey, capturing keys exactly when the video player uses them.


🔥 Key Features

In-Browser Decryption: Merges and decrypts TS segments automatically. No FFmpeg needed.
Brute-Force Matcher: Tests captured keys against segments by verifying the MPEG-TS Sync Byte (0x47), ensuring perfect key-to-segment mapping.
Web Crypto No-Padding Workaround: Bypasses strict PKCS7 padding requirements of the Web Crypto API using synthetic padding.