MPEG-CENC: Defective by Specification (2024)
5 hours ago
- DRM systems are 'defective by design', and MPEG-CENC is commonly used but flawed.
- DeCENC is a generic attack that exploits the lack of authentication in MPEG-CENC encryption.
- The attack uses I_PCM macroblocks to bypass video decoders, allowing decrypted data to be recovered from screen captures.
- It manipulates standard EME and MSE APIs, making it portable across different CDMs.
- Challenges include NAL emulation prevention, chroma subsampling, limited range color, and metadata constraints.
- Mitigations involve switching to authenticated encryption (AEAD), but rollout is slow.
- Proof-of-concept source code is available on GitHub.