Supply Chain Authentication Without PKI

1. Regulatory and Compliance Framework

Supply-chain authentication is no longer a discretionary security posture. It is a regulated obligation under a converging stack of federal and international rules. Executive Order 14028 on Improving the Nation's Cybersecurity directs federal agencies and their software suppliers to produce verifiable software bills of materials (SBOMs) and to authenticate the provenance of every component delivered into federal systems; NIST Special Publication 800-161 Revision 1 (Cybersecurity Supply Chain Risk Management Practices for Systems and Organizations) operationalizes that directive into control families covering supplier identity, component integrity, and tamper evidence across multi-tier supply networks. NIST SP 800-218 (the Secure Software Development Framework) and the related self-attestation form issued by CISA require software producers selling into the federal market to attest to specific provenance and integrity practices, and to do so in a manner that survives downstream redistribution.

In the physical-goods domain, the FDA Drug Supply Chain Security Act (DSCSA) reached its full enforcement posture in 2024, requiring interoperable, electronic, package-level traceability for prescription drugs from manufacturer through dispensing pharmacy. Authorized Trading Partner (ATP) verification under DSCSA is fundamentally an authentication problem: every transaction must demonstrate that the counterparty is licensed and that the product unit's identifier has not been cloned or substituted. The Uyghur Forced Labor Prevention Act (UFLPA) imposes a rebuttable presumption against goods with any nexus to the Xinjiang Uyghur Autonomous Region, which in practice forces importers to authenticate component-level origin claims back through multiple supplier tiers. The CHIPS and Science Act and Department of Commerce semiconductor supply-chain rules add similar provenance requirements for advanced node integrated circuits, and the Infrastructure Investment and Jobs Act (IIJA) Build America, Buy America (BABA) provisions require iron, steel, manufactured products, and construction materials in federally funded infrastructure to be authenticated as domestically produced.

On the international side, the EU Cyber Resilience Act, EU Digital Product Passport regulations under the Ecodesign for Sustainable Products Regulation (ESPR), and the EU Battery Regulation 2023/1542 each impose component-level authentication and lifecycle traceability that span jurisdictions. The common architectural demand across all of these regimes is the same: authenticate entities, components, and units across organizational and jurisdictional boundaries in a way that is verifiable by parties who do not share a trust anchor.

2. Architectural Requirement

Strip away the regulatory verbiage and a single structural requirement remains: every participant in a supply chain must be able to verify the identity and integrity of every other participant's contribution without depending on a trust authority that all participants share. The supply chain has no central operator. There is no equivalent of the federal government for a multinational pharmaceutical chain, no single regulator for a battery cathode that is mined in the DRC, refined in Indonesia, processed in Korea, and assembled into a pack in Tennessee. Each tier has its own jurisdictional regulator, its own certificate practices, and its own commercial sensitivities about disclosing supplier relationships.

What the regulator structurally requires is therefore boundary-spanning authentication: a property of the authentication system itself, not of the participants. The system must allow Tier-3 supplier authentication to be evaluated at Tier-0 (the brand owner or end user) without Tier-3 having any prior trust relationship with Tier-0, and without any intermediate tier acting as an unverifiable proxy. It must also permit the verification to survive participant churn — suppliers go bankrupt, get acquired, change names, change certificate authorities — without invalidating prior authenticated history. And it must produce verifiable artifacts that downstream regulators (FDA inspectors, CBP officers, EU market-surveillance authorities) can re-evaluate years later, after the original participants and their PKI infrastructure may no longer exist.

The architectural shape these requirements describe is identity that accumulates as a function of interaction history and is locally verifiable from that history, rather than identity that is asserted by a credential issued by an authority that all parties must trust. Whether the system uses cryptographic keys at all becomes a secondary question; what matters is that the verifiable identity property survives the failure or absence of any single trust authority.

3. Why Procedural Compliance Fails

The dominant response to supply-chain authentication regulation has been procedural: contractual flow-down clauses, supplier questionnaires, third-party audits, blockchain pilots, and bilateral PKI cross-certifications. None of these produce the structural property the regulators are reaching for, and the failure modes are well documented.

Contractual flow-down assumes that the party at Tier-N reads, understands, signs, and complies with provisions originating at Tier-0. Empirical evidence from DSCSA implementation, conflict-minerals reporting under Dodd-Frank Section 1502, and UFLPA enforcement actions all show that flow-down breaks within two tiers; by Tier-3 the original obligation is unrecognizable, and by Tier-4 the documents themselves are often forged. Supplier questionnaires are self-attestation; they detect honest suppliers but provide no defense against deliberate misrepresentation, and they are the standard vector for document-fraud audits to land. Third-party audits visit a defined site at a defined time; they are systematically gamed through ghost factories, rented production lines, and pre-staged inventory.

Cross-PKI authentication is technically rigorous but fails operationally because every additional cross-certification expands the attack surface to include every participating CA. A 2024 compromise of a mid-tier CA used by three semiconductor suppliers cascaded into questioned authenticity for thousands of downstream parts. Blockchain-based traceability platforms (IBM Food Trust's evolution, MediLedger, the various battery-passport pilots) replace the central CA with a consortium ledger but reproduce the same problem: the consortium becomes the trust authority, and any compromise of consortium key management compromises the whole chain. They also do not solve the core problem that whatever is written into the ledger must originate from some authenticated input event, and the authentication of that input event is still unsolved.

Procedural compliance, in short, produces records that satisfy auditors at the moment of audit and fails to produce evidence that survives later forensic examination. Regulators are increasingly asking the second question, and the procedural stack has no answer.

4. What the AQ Keyless-Identity Primitive Provides

The Adaptive Query keyless-identity primitive, disclosed under USPTO provisional 64/050,895, specifies that an entity's verifiable identity is a structural property of its accumulated interaction history rather than a credential issued by a trust authority. Every interaction between two entities extends each entity's hash chain with locally sourced entropy contributed by both parties; each chain extension is therefore co-authored, and the resulting trust slope of an entity is the cumulative consistency of its co-authored history with its claimed operational profile. The identity is not stored, not revocable in the certificate sense, and not transferable; it cannot be cloned by an attacker who lacks access to the actual interaction history of the device or organization.

Verification is local. Given an entity's claimed identity and a sample of its co-authored history, a verifier evaluates whether the trust slope is consistent with the claim. Counterfeit devices that present cloned identifiers but lack genuine co-authored interaction history fail verification regardless of how perfectly they replicate the public identifier. Compromised participants whose interaction history shows discontinuities relative to the expected operational profile fail verification regardless of whether their cryptographic credentials are formally valid. Post-quantum resilience is intrinsic because the verification depends on the structure of accumulated history, not on the hardness of factoring or discrete-log problems.

Boundary-spanning verification is the load-bearing property. Because the trust slope is locally evaluable from the co-authored interaction history, a Tier-0 verifier can evaluate a Tier-3 entity's identity without any shared CA, without any intermediate party vouching, and without any consortium ledger. Each intermediate interaction contributed a co-authored extension to both parties' chains; the resulting history is its own evidentiary substrate. The primitive is technology-neutral with respect to underlying hash and entropy primitives, composes hierarchically (component, assembly, shipment, consignment), and degrades gracefully under participant churn because prior co-authored history retains its evidentiary value even after a participant ceases to operate.

5. Compliance Mapping

The mapping from the AQ primitive to specific regulatory obligations is direct. NIST SP 800-161r1 controls SR-3 (Supply Chain Controls and Processes), SR-4 (Provenance), and SR-11 (Component Authenticity) all describe outcomes that the trust slope produces structurally rather than procedurally; the keyless-identity chain is the artifact a federal acquirer can require and a federal inspector can re-evaluate. EO 14028 and the CISA self-attestation form's provenance-verification requirements are satisfied by trust-slope verification of each component's accumulated history at each integration point, and the resulting verification record is itself a co-authored chain extension that downstream parties can re-verify.

For DSCSA Authorized Trading Partner verification and unit-level traceability, the trust slope of a packaged unit's serialization device authenticates both the unit identifier and the trading-partner identity in a single local evaluation, replacing the FDA-anticipated but operationally fragile network of bilateral GS1-based PKI exchanges. UFLPA rebuttable-presumption documentation is converted from a paperwork exercise into a structural showing: the importer can present trust-slope verification of each upstream tier's co-authored history, and CBP can re-evaluate that history without dependence on any specific tier's continued cooperation. BABA domestic-content authentication under IIJA-funded projects, EU Digital Product Passport content claims under ESPR, and EU Battery Regulation due-diligence obligations all reduce to the same structural showing.

Critically, the same chain that satisfies one regulator satisfies all of them. The trust slope is jurisdiction-neutral; FDA, CBP, EU market-surveillance authorities, and DOE BABA reviewers all evaluate the same evidentiary substrate against their respective rule sets. Operators no longer maintain parallel compliance stacks for parallel regulators.

6. Adoption Pathway

Operator deployment of keyless-identity authentication proceeds in three stages aligned with how supply-chain operators actually buy and integrate authentication technology. Stage one is component-level enablement. Device vendors — sensor manufacturers, RFID and 2D-barcode readers, programmable logic controllers, serialization printers, telematics units — embed trust-slope generation into the device firmware. Industry partners with the manufacturing scale to drive this stage include the established industrial-IoT vendors (Honeywell, Emerson, Siemens, Schneider Electric) for sensor and controller embedding, the auto-ID specialists (Zebra, Datalogic, Cognex) for scanning and reader embedding, and the serialization vendors (Systech, Antares Vision, Optel) for pharmaceutical and consumer-goods unit-level marking.

Stage two is platform integration. The supply-chain visibility, traceability, and procurement platforms that operators already use — SAP Ariba, Oracle Fusion SCM, Blue Yonder, e2open, project44, FourKites, Tive, the various GS1-based traceability networks, and the emerging digital-product-passport platforms — integrate trust-slope verification as a native input to their existing authentication and provenance workflows. The integration point is well defined: where these platforms today consume a digital signature or a CA-rooted certificate as proof of an event, they additionally consume a trust-slope verification artifact, and they propagate the artifact downstream as a co-authored chain extension. Existing PKI continues to work for participants who have it; trust-slope verification provides the boundary-spanning property that PKI cannot, without forcing a rip-and-replace.

Stage three is regulatory attestation. Operators deploy attestation gateways that translate trust-slope verifications into the specific report formats each regulator requires: DSCSA T3 (Transaction Information / Transaction History / Transaction Statement) packages for FDA, CBP Form 7501 supporting documentation for UFLPA and BABA, CRA conformity-assessment artifacts for EU market entry, ESPR Digital Product Passport entries, and federal-acquirer SBOM and provenance attestations under EO 14028 and CISA self-attestation. The gateway is thin; the evidentiary substrate is the trust-slope chain itself, and the gateway produces regulator-formatted views over it.

Commercial framing for the operator is straightforward. Existing authentication and provenance investments — PKI, blockchain pilots, supplier audits — continue to operate; the AQ primitive layers underneath as the structural substrate that makes those investments survive boundary crossings and participant churn. The operator gains a single evidentiary artifact that satisfies multiple regulators, post-quantum resilience for free, and forensic durability that no certificate-based system can match. The supply-chain authentication problem stops being a perpetual procurement and audit overhead and becomes a structural property of how the chain operates.