Sdde-721 -

The SDDE-721 boasts an impressive array of features that set it apart from other digital signage solutions in the market. Some of its key features include:

| Test | Description | |------|-------------| | | Verify HKEX completes with both classic + PQ components. | | Cipher‑Suite Negotiation | Confirm both peers agree on a suite supported by each device’s capability table. | | Replay Test | Send a captured data frame with an older sequence number – receiver must reject. | | Policy‑Enforcement Test | Deploy a policy that denies a specific topic; ensure the data is dropped and an error is logged. | | Fragmentation Test | Transmit a 5 MiB payload over a 127‑byte MTU link – verify correct reassembly without state loss. | sdde-721

| Component | Recommended Practice | |-----------|----------------------| | | Store in a Trusted Platform Module (TPM) or Secure Element; rotate annually. | | Session Keys | Derive via HKDF‑SHA‑384; store only in volatile RAM. | | Policy Keys | Use ECDSA‑P‑256 signatures; maintain a revocation list at the edge gateway. | | KMS Integration | SDDE‑721 defines a REST‑ish KMS API (JSON‑Web‑Key format) for cloud‑backed key retrieval. | The SDDE-721 boasts an impressive array of features

| Feature | | TLS 1.3 (RFC 8446) | DTLS 1.3 (RFC 9146) | OSCORE (RFC 8613) | |---------|--------------|-------------------|---------------------|----------------------| | Transport‑agnostic | ✅ (MFL can sit on any transport) | ❌ (TCP‑only) | ✅ (UDP only) | ✅ (CoAP‑specific) | | Hybrid PQ KEM | ✅ (Kyber + X25519) | ❌ (classic only) | ❌ | ❌ | | Adaptive Cipher Suite | ✅ (runtime selection) | ✅ (via negotiation) | ✅ | ❌ (fixed AEAD) | | Stateless Replay Protection | ✅ (DRP) | ❌ (requires per‑session state) | ✅ (but stateful) | ✅ (sequence numbers, needs memory) | | Policy Language | ✅ ( | | Replay Test | Send a captured

The specification a specific transport‑layer protocol; instead, it defines a Message‑Format Layer (MFL) that can be encapsulated in any byte‑stream.