Quantum Key Distribution Patents

Quantum key distribution patents cover single photon source and detector innovations; QKD protocol implementation and decoy state innovations; continuous variable CVQKD modulation and reconciliation innovations; and quantum network quantum repeater and memory innovations — with IP held by quantum optics companies, national labs, and defense contractors: MAJOR QKD PATENT HOLDERS: ID QUANTIQUE: 500+; specific QKD innovations (specific specific Clavis3 QKD platform: specific specific BB84 weak coherent pulse WCP decoy state from specific specific 1,550 nm C-band telecom from specific specific InGaAs SPAD clock 100 MHz from specific specific detector efficiency 25% at 1,550 nm from specific specific dark count rate 1 kHz at 100 MHz gating from specific specific channel: specific specific QBER quantum bit error rate 2-3% from specific specific 80 km SMF standard single-mode fiber from specific specific secure key rate SKR 10-100 kbps 80 km from specific specific privacy amplification: specific specific universal hashing from specific specific Toeplitz matrix from specific specific SKR = (1-2h(e_b))-h(e_b) from specific specific Cerberis server: specific specific QRNG quantum random number generator from specific specific PCIe board integration from specific specific 1 Gbps random output); TOSHIBA: 300+; specific QKD innovations (specific specific DPS differential phase shift: specific specific train of pulses from specific specific 200 MHz clock 1,550 nm from specific specific InGaAs InP SPAD 200 MHz from specific specific TF-QKD twin-field: specific specific 300+ km distance from specific specific midpoint detection Charlie from specific specific √N scaling loss vs. N repeat.; specific specific T12 system); BATTELLE MEMORIAL INSTITUTE: 200+; MAGIQ TECHNOLOGIES: 100+; QUANTINUUM: 200+.

BB84 photon polarization or phase encoding and measurement basis choice innovations; continuous variable CVQKD Gaussian modulation and homodyne detection innovations; and decoy state method and photon number splitting attack mitigation innovations represent core QKD patent domains: BB84 PROTOCOL PATENTS: ID QUANTIQUE; MIT LL; LOS ALAMOS; BBN TECHNOLOGIES; TOSHIBA: specific BB84 innovations (specific specific BB84 original protocol: specific specific BB84 Bennett Brassard 1984 prior art expired from specific specific decoy state method: specific specific Hwang 2003 Lo Ma Chen 2004 patent active from specific specific vacuum+weak decoy multi-intensity from specific specific n=0,1,2 photon number fraction from specific specific multi-decoy 3 intensities μ ν ω from specific specific finite-key security bound from specific specific photon number resolving PNR: specific specific TES transition edge sensor from specific specific 98% efficiency 1,310 nm from specific specific 1 μK superconducting from specific specific SNSPD: specific specific NbN 2.5 nm NbTiN from specific specific 93-98% efficiency 1,550 nm from specific specific 70-100 ps jitter from specific specific 1,000 Hz dark count from specific specific measurement device independent MDI-QKD: specific specific star topology from specific specific Bell state measurement at Charlie from specific specific removes detector side channel from specific specific HOM interference V 99%+ from specific specific 50 km each arm 200 km total); CVQKD PATENTS: QUINTESSENCE LABS; XANADU; SEQURENET/SORBONNE; CEA: specific CVQKD innovations (specific specific Gaussian-modulated CVQKD: specific specific coherent state displacement α from specific specific Gaussian modulation σ²: 2-40 shot noise from specific specific homodyne heterodyne detection from specific specific shot noise unit SNU normalization from specific specific composable security finite size from specific specific LLO local local oscillator from specific specific pilot tone 2% frame from specific specific 20-30 km reconciliation efficiency β 0.95 from specific specific LDPC low-density parity check from specific specific Slepian-Wolf information reconciliation from specific specific excess noise ε 0.01-0.02 SNU from specific specific CV-MDI-QKD: specific specific Gaussian post-selection from specific specific 40 km each arm metropolitan); DECOY STATE PATENTS: LO/TORONTO; HWANG/KOREA; TOSHIBA; ID QUANTIQUE: specific decoy innovations (specific specific 4-intensity decoy: specific specific signal μ=0.6 decoy ν=0.1 vacuum ω=0 + calibration from specific specific Poissonian WCP photon statistics from specific specific gain Q_μ yield Y₁ from specific specific phase random from specific specific SKR = q[Q₁(1-h₂(e₁))-f Q_μ h₂(E_μ)] from specific specific infinite-key finite-key correction from specific specific 10^10 pulses per second clock from specific specific Shor-Preskill security proof 2000).

Quantum network quantum repeater and entanglement distribution innovations; quantum memory and matter qubit interface innovations; and post-quantum cryptography lattice-based and code-based algorithm innovations represent additional quantum cryptography patent domains: QUANTUM NETWORK PATENTS: DELFT UNIVERSITY; MIT; STANFORD; CALTECH; AT&T RESEARCH: specific quantum network innovations (specific specific quantum repeater: specific specific entanglement purification: specific specific distillation protocol 2→1 Bell state from specific specific quantum error correction QEC from specific specific CNOT+measurement from specific specific quantum memory: specific specific alkali vapor Rb Cs SEOP from specific specific EIT electromagnetically induced transparency from specific specific storage time 1 ms 300 K from specific specific AFC atomic frequency comb from specific specific Pr:YSO crystal 1 μs at 2 K from specific specific DLCZ protocol: specific specific probabilistic write-read Raman from specific specific collective excitation from specific specific heralded entanglement from specific specific entanglement swapping: specific specific Bell state measurement BSM at repeater from specific specific EPR pair distribution rate from specific specific satellite QKD: specific specific Micius satellite 2016 China from specific specific 600 km LEO from specific specific BBM92 entanglement-based from specific specific 10⁻²¹ W/m² signal 1,200 km from specific specific quantum network stack: specific specific photon-to-matter qubit interface from specific specific NV center diamond Si V center from specific specific neutral atom Rb Cs trapped-ion Ca⁺ from specific specific quantum internet alliance QIA protocols); POST-QUANTUM CRYPTOGRAPHY PATENTS: MICROSOFT; PQSHIELD; QUANTINUUM; NIST PARTNERS; SRI: specific PQC innovations (specific specific NIST PQC 2024 selected standards: specific specific ML-KEM CRYSTALS-Kyber lattice KEM from specific specific Module-LWE ring-LWE hardness from specific specific Kyber512 128-bit quantum 1,632 byte public key from specific specific ML-DSA CRYSTALS-Dilithium signature 2,420 byte from specific specific SLH-DSA SPHINCS+ hash-based 8,080 byte from specific specific FN-DSA FALCON NTRU 897 byte from specific specific lattice hardness: specific specific LWE learning with errors from specific specific RLWE ring-LWE n=256 q=3329 from specific specific quantum cryptanalysis: specific specific Grover 2× symmetric key length from specific specific Shor breaks RSA ECC completely from specific specific AES-256 secure post-quantum from specific specific hybrid scheme: specific specific ECDH+ML-KEM combined from specific specific X25519MLKEM768 NIST transition).

Quantum cryptography startup IP strategy must navigate ID Quantique (500+) and Toshiba (300+) QKD implementation IP; understand that BB84 original protocol has expired prior art, but decoy state methods and CVQKD implementations have active IP; identify whitespace in quantum network protocols, quantum memory integration, post-quantum cryptography hardware acceleration, and hybrid classical-quantum key management systems — while understanding that post-quantum cryptography (NIST 2024 standards) is a massive commercial opportunity that requires implementation IP rather than algorithm IP: QUANTUM CRYPTOGRAPHY STARTUP IP STRATEGY: UNDERSTAND THE QKD PATENT LANDSCAPE — ID QUANTIQUE AND TOSHIBA HOLD CORE QKD IMPLEMENTATION IP: ID Quantique (500+) and Toshiba (300+) hold broad QKD system implementation IP covering specific hardware configurations, QBER management, and key management protocols; BB84 core protocol is public domain (expired prior art) — the commercial IP is in specific fast detector gating, decoy state parameter optimization, and SNSPD integration; POST-QUANTUM CRYPTOGRAPHY HARDWARE ACCELERATION IS THE HIGHEST-VALUE LEAST-CONSOLIDATED IP DOMAIN: NIST 2024 standards (ML-KEM, ML-DSA, FALCON) are now finalized — implementation IP for hardware acceleration (FPGA ASIC ML-KEM lattice arithmetic NTT number theoretic transform) and embedded systems PQC represents a rapidly growing patent domain; Microsoft, PQShield, and SRI hold early hardware PQC IP but there is significant whitespace; QUANTUM NETWORK PROTOCOLS AND MEMORY INTERFACES ARE THE FRONTIER: Delft, MIT, and Caltech quantum repeater and memory IP represents early-stage work — commercial quantum network nodes integrating NV center diamond or neutral atom qubits with telecom photons represent genuinely novel IP territory with few granted commercial patents; WHEN TO PATENT IN QUANTUM CRYPTOGRAPHY: NOVEL QKD SYSTEM OR PQC HARDWARE WITH MEASURED SECURITY METRICS: specific novel quantum cryptography invention (specific specific protocol/system + specific specific hardware platform + specific specific security level) with specific measured performance (specific specific secure key rate kbps at specific specific distance km + specific specific QBER % at specific specific loss dB + specific specific NTT operations per second for PQC + specific specific energy per operation pJ for embedded PQC + specific specific key generation rate keys/sec) vs. specific specific ID Quantique Clavis3 80 km 10-100 kbps or specific specific PQShield ASIC ML-KEM 1,000 ops/sec 0.1 mJ or specific specific SNSPD 93-98% efficiency 70 ps baseline — measured SKR at distance or PQC throughput vs. commercial benchmark is the critical quantum cryptography IP metric; KEY FTO CHECKLIST: ID Quantique BB84 decoy WCP 100 MHz InGaAs SPAD 25% 1 kHz 80 km 2-3% QBER 10-100 kbps privacy amp Toeplitz; Toshiba DPS 200 MHz TF-QKD 300 km midpoint Charlie √N scaling; SNSPD NbN 93-98% 70 ps 1,000 Hz dark 1,550 nm TES 98% PNR 1,310 nm; MDI-QKD star BSM HOM V 99% 200 km; CVQKD Gaussian homodyne SNU LLO pilot β 0.95 LDPC ε 0.01 SNU 40 km; Micius 600 km LEO BBM92 10⁻²¹ W/m²; ML-KEM Kyber512 1,632 byte LWE 128-bit quantum; ML-DSA Dilithium 2,420 byte; FALCON NTRU 897 byte; SLH-DSA SPHINCS+ hash 8,080 byte; AES-256 Grover secure; X25519MLKEM768 hybrid NIST transition.