Zero-Knowledge Cryptographic Evidence Commitments and Merkle Inclusion Proofs for Continuous Enterprise Third-Party Security Assurance

Continuous third-party cyber risk mandates under EU NIS2 Article 21(2)(d), DORA Article 28, ISO/IEC 27001:2022, and AICPA SOC 2 Trust Services Criteria confront a fundamental security paradox: enterprise buyers demand verifiable, tamper-evident proof that a vendor's security controls (vulnerability remediation SLAs, key rotation epochs, encryption coverage, and penetration-test remediation states) continuously hold, yet transmitting raw infrastructure configurations, network topologies, and unredacted vulnerability scans to dozens of external customer portals creates catastrophic attack-surface concentration. Static PDF attestations suffer from point-in-time staleness, while naive unprefixed hash trees remain vulnerable to internal-node-as-leaf second-preimage forgeries and dictionary brute-forcing over low-entropy PASS/FAIL states. This technical note formalizes a zero-egress cryptographic assurance protocol combining 256-bit nonce-blinded RFC 8785 control commitments, RFC 9162 domain-separated binary Merkle inclusion and append-only consistency proofs, and non-interactive zero-knowledge (NIZK) threshold predicates enabling O(log n) selective audit verification without raw artifact disclosure. Reference Verification Implementation: https://titantrustcenter.com (Maintained by TITAN Capital Forensics LLC, Albuquerque, New Mexico, USA; D-U-N-S: 33-195-8002; UNGM: #1299169). Zero source code or executable software distributed.