Under jamming and contested spectrum, standard tactical crypto cliffs — one flipped bit and an AEAD discards the whole command; a dropped packet and the handshake never completes, so the link dies. QSDP is a true bit-stream cipher with single-use, information-theoretic keys that degrades gracefully instead — holding command authority where every other protocol falls to zero.
QSDP — the QuStream Defence Protocol — is a cryptographic protocol for environments where the communications channel is degraded by noise, jamming, or contested-spectrum pressure. It runs as an inline bit-stream proxy between the transport and the host system, encrypting and authenticating every message under a single-use key derived from a mission-unique, high-entropy Q-Block and a per-message rotating Path Derivation Key (PDK).
It is format-agnostic — MAVLink, CRSF, SBUS, raw video — and adds just 8 bytes of overhead per packet. There is no block boundary, no full-message MAC, and no handshake to break.
Standard tactical crypto fails the moment bits get corrupted. AEAD protocols (AES-GCM, ChaCha20-Poly1305) discard the entire message on any tag-verification failure — one flipped bit and the whole command is lost. Block-mode protocols cannot decrypt until a full 16-byte block arrives intact. Rotating systems — ECDH, post-quantum KEMs such as ML-KEM — need multi-packet handshakes that cannot survive heavy EW, and the link dies entirely.
QSDP is a true bit-stream cipher with single-use, per-message keys carrying information-theoretic guarantees, plus an embedded dictionary of valid commands. Damaged bits are reconstructed from the nearest valid dictionary entry and prior message context — so the result is graceful degradation under noise where every other protocol cliffs.
Information-theoretic confidentiality — harvest-now-decrypt-later immune, resting on no conjectured hardness.
Native one-way and high-latency operation with forward secrecy — works on space and subsurface links where handshakes can't.
An authenticated frame ~20 B smaller than AES-GCM — a measured goodput and energy edge on constrained links.
0% wrong commands under corruption, where AES-PSK can accept up to 100% corrupted as valid.
Parity, stated plainly. On raw channel survivability against a properly-engineered AES stack carrying identical FEC and diversity, QSDP is at parity — not ahead. Its genuine edge is integrity, key model, and overhead, not raw error-correction. A comparison that hid that would not be credible.
| Property | AES-PSK | AES-GCM | ECDH + GCM | ML-KEM + GCM | QSDP |
|---|---|---|---|---|---|
| Goodput under combined attack — % commands delivered correctly | |||||
| Surface RF — light mixed attack2 | 44% | 26% | 12%1 | 0%1 | 66% |
| Surface RF — moderate mixed attack2 | 28% | 9% | 0%1 | 0%1 | 36% |
| Surface RF — heavy mixed attack2 | 0% | 2% | 0%1 | 0%1 | 14% |
| Subsurface acoustic UUV — sonar jamming3 | 35% | 23% | — | — | 44% |
| Subsurface acoustic UUV — heavy combined3 | 23% | 14% | — | — | 28% |
| Submarine VLF atmospheric — BER 0.5%3 | 57% | 27% | — | — | 74% |
| Submarine VLF jammed — 20% loss + BER 1%3 | 23% | 4% | — | — | 46% |
| Underwater optical — high turbidity3 | 30% | 22% | — | — | 34% |
| Protocol properties | |||||
| Per-message forward secrecy | No | No | Per session | Per session | Yes |
| Post-quantum secure | Yes | Yes | No | Yes | Yes |
| Capture exposure | Whole fleet? | Whole fleet? | One session | One session | One message |
| Wire overhead per packet | 8 B | 28 B | 29 B + HDSK | 29 B + 2.3 KB | 8 B |
| Forgery DoS amplification | 1.0× | 1.1× | n/a (dies) | n/a (dies) | 0.07× |