The first practical implementation of Operational Perfect Secrecy (OPS) for data-plane confidentiality.
Most quantum-safe products protect the key exchange layer — the handshake before data flows. QuStream protects the data plane itself, using Operational Perfect Secrecy (OPS) to extend information-theoretic security (ITS) into every byte of traffic.
OPS is a formal generalisation of Shannon's 1949 perfect secrecy theorem. It bounds adversarial success probability to ≤ 2−t, independent of computing power — classical or quantum. Unlike PQC, whose security rests on computational hardness assumptions, OPS provides unconditional confidentiality.
Key exchange layer
PQC (ML-KEM) operates here
Q-Stream overlay layer
QuStream operates here — OPS encryption
Application layer
Standard protocols unchanged
QuStream deploys as a transparent overlay. It intercepts traffic at the data plane, applies OTP-based encryption using MEKs derived from public Q-Blocks, and passes traffic downstream. Integration is non-disruptive to existing TLS, AES, or QKD infrastructure.
The machinery behind Practical Information-Theoretic Security.
Large blocks of high-entropy quantum-random bits generated by QRNGs. They are distributed publicly and contain no secrets in isolation. Their combinatorial richness underpins OPS security.
Short Defragmentation Keys that reveal the location of the next session key inside a Q-Block. DFKs form a forward-linked chain: each used key reveal the location of its successor before being destroyed.
Message-Encryption Keys extracted from Q-Blocks via the extraction function F(D, Q). Each MEK is used exactly once for XOR encryption (C = M ⊕ K), ensuring strict Shannon-grade confidentiality.
Part of the trusted computing base. They generate Q-Blocks from QRNGs and maintain the minimal synchronization state required for device onboarding and session recovery.
Relay nodes that operate within your enterprise perimeter. They hold no cryptographic stateand cannot observe or derive MEKs from the traffic they relay. They provide transport-layer scalability without increasing the trust boundary.
PQC (ML-KEM, ML-DSA) handles authentication and key negotiation. QuStream handles confidentiality. Running both provides defence in depth: PQC for identity verification, OPS for unconditional data-plane secrecy.
QKD secures node-to-node links, but end-device delivery often reintroduces computational assumptions. QuStream embeds QKD keys into Q-Blocks, extending information-theoretic security to endpoints without trusted relay nodes.
By decoupling security logic from the data flow, QuStream achieves line-rate performance unreachable by computational algorithms.
Data Plane: Pure combinational XOR. Structural latency floor: ~4–6 ns at 100 Gbit/s.
Control Plane: Handles Q-Block sequencing, synchronization, and integrity on a separate channel.
Explore how Operational Perfect Secrecy fits into your existing network architecture. Download the implementation guide and review our reference architecture.