Post-Quantum Cryptography in immo.quick Core/Machine Law

This paper presents the first formally documented implementation of post-quantum cryptographic infrastructure within a production-grade institutional compliance enforcement system. It addresses a structural vulnerability endemic to the entire regulatory technology industry: every compliance record generated today under RSA or ECC encryption is potentially exposed to "Harvest Now, Decrypt Later" (HNDL) attacks — a documented, operationally active collection strategy confirmed by NSA, CISA, ENISA, and BSI — and will remain so until quantum computers capable of running Shor's algorithm at scale become available, currently projected between 2030 and 2035. Given mandatory regulatory retention periods of 5–30 years under DORA Art.10, GDPR Art.5(e), FinCEN BSA 31 CFR §103.33, Swiss OR Art.958f, and Solvency II, compliance records created today under classical cryptography will still exist — and may be decryptable — within their own legally mandated retention window. This paper documents the complete architectural response: the deployment of CRYSTALS-Kyber-1024 (NIST FIPS 203, 2024) as the primary cryptographic primitive for all compliance ledger operations in the immo.quick Core Machine Law Engine, combined with: A hybrid encryption architecture providing quantum security with full backward compatibility A Merkle Tree Batching scheme reducing post-quantum storage overhead by 99.99% (from 4.67 PB/year to 0.35 TB/year at Tier-1 clearing volumes) A multi-region HSM key hierarchy (EU/CH/US/UK) with Shamir Secret Sharing (3-of-5) and zero-downtime rotation A Zero-Knowledge Proof integration (Groth16, PLONK, Cairo zk-STARK) that resolves the structural contradiction between GDPR Art.17 erasure rights and immutable ledger requirements — by placing zero personal data on the ledger A crypto-agility policy engine enabling algorithm migration without application code changes or audit trail disruption Complete regulatory compliance mappings to DORA, GDPR, BSI TR-02102-1, and NIST FIPS 203 The immo.quick Core platform is presented as the first operational implementation of this architecture across fourteen regulatory frameworks and five institutional sectors (Real Estate, Banking, Insurance, Government, Cloud/FinTech). This paper is a standalone technical specification and supplements the immo.quick Core architecture series (DOI: 10.5281/zenodo.19301212 through 10.5281/zenodo.19457223). It provides the first focused, formally structured academic documentation of CRYSTALS-Kyber-1024 deployment within a deterministic gate enforcement environment with hardware TEE attestation and bi-temporal legal state management. The central argument: Post-Quantum cryptography is not a feature request for 2030. It is a structural prerequisite for any compliance system intended to produce legally defensible evidence chains beyond the quantum threat horizon. The architecture to achieve this exists, is formally specified, and is operationally deployed.