The Vulnerable Moment
Bootstrap is the moment when FHE re-encrypts to refresh noise -- the ciphertext boundary is briefly exposed. Every FHE system has this exposure window. NINE65 v7 protects it with three independent, nested security layers that must ALL be broken simultaneously.
Three Locks
Shannon Mask
(Outermost)
Information-theoretic protection. Even with unlimited computational power, masked values reveal zero bits about the plaintext. Grounded in one-time pad theory -- the gold standard of theoretical cryptography.
RLWE Outer Encryption
(Middle)
Computational hardness barrier. Even if the Shannon mask were compromised, the ciphertext remains protected by lattice-based encryption. Security reduces to the Ring Learning With Errors problem -- a foundation of post-quantum cryptography.
Clockwork Inner
(Core)
The re-encryption mechanism itself. A depth-1 homomorphic operation that refreshes noise budget for unlimited depth. During execution, it is shielded by both outer layers -- never exposed directly.
Conjunction Security
An attacker must break all three locks simultaneously -- information-theoretic certainty AND computational hardness AND algebraic structure. Compromising one layer reveals nothing useful because the remaining locks still protect the plaintext. This is defense-in-depth applied to cryptographic protocol design.
Three Bootstrap Paths
Derived Key Bootstrap
boot_sk derived from work_sk. Verified -- exact plaintext recovery across all test messages.
Independent Key Bootstrap (KSK)
Independent boot_sk with gadget key switch. No circular security assumption required. Verified -- exact plaintext recovery.
Automatic Trigger
Fires automatically when noise budget drops below threshold. Verified -- 10+ chained multiplications with exact results. Unlimited computational depth.
Verification
Bootstrap Tests
78 bootstrap-specific tests, all passing. Covers circular security, modswitch correctness, and key generation.
Formal Proofs
Formal proofs covering circular security, modswitch correctness, and key generation. Verified in Coq and Lean4.
Pending formal external cryptographic audit.
Interested in Licensing?
NINE65 v7 with Three-Lock conjunction security is available for licensing. Get in touch to discuss integration, security requirements, and commercial arrangements.