x402 V2 / Vauban Claim Algebra / FIPS 204
Cryptographic proof layer for regulated AI and agent payments
Post-quantum, EU-compliant, audit-grade. No facilitator round-trip needed.
Three independent axes over one shared payment_hash.
Three independent verification axes, one shared anchor
Each axis is produced and verified independently.
All three bind to the same payment_hash and action_ref.
Axis 1 -- STARK proof of payment conditions
Vauban
Circle STARK (Stwo M31) receipt proves amount, currency, payer attestation,
and nullifier without revealing them. Post-quantum by construction. No trusted
setup. Bound to the same payment_hash as the other axes.
Axis 2 -- Hybrid post-quantum signature
FeedOracle coalition
ES256K + ML-DSA-65 (FIPS 204) over canonical JCS bytes per RFC 8785. NIST IR 8547 transition-compliant. EU PQC Roadmap-aligned. Dual signature: one classical, one lattice-based -- both required for acceptance.
Axis 3 -- Work-receipt binding
andysalvo coalition
action_ref = SHA-256(JCS(preimage)) per RFC 8785.
Pure 32-byte hash binding the payment to whatever the agent produced after.
No ZK overhead. Verifiable by any HTTP client without a prover.
What regulators actually need
Vauban Pay produces machine-verifiable receipts that map directly to record-keeping obligations in four regulatory frameworks.
EU AI Act Art. 12
Logging obligations for general-purpose AI
Art. 12 requires general-purpose AI systems to log operations with sufficient granularity for post-hoc audit. Vauban Pay's STARK receipt provides a tamper-evident, cryptographically bound record of each payment action.
MiCA Art. 76
Record-keeping for crypto asset service providers
MiCA Art. 76 mandates that CASPs maintain records of all services and transactions for five years. The composite receipt (STARK + hybrid-PQC signature + action-ref) provides a self-contained, verifiable record that survives long-term storage.
DORA (EU 2022/2554)
Operational resilience for financial services
DORA requires financial entities to maintain resilient ICT systems and retain logs for forensic investigation. Vauban Pay receipts are offline-verifiable: no live RPC call needed to confirm a historical payment.
NIST IR 8547
Post-quantum cryptographic transition
NIST IR 8547 documents the deprecation timeline for classical algorithms against quantum adversaries. Axis 2 uses ML-DSA-65 (FIPS 204) alongside ES256K. Axis 1 (Circle STARK) is post-quantum by construction.
Reproducible across four independent implementations
Each coalition member independently produced a fixture against the same
payment_hash and action_ref. No shared code.
Early access for regulated institutions
Vauban Pay is in Phase 0 design partner selection. We are looking for EU-regulated AI providers, payment service providers, and fintech platforms subject to EU AI Act, MiCA, or DORA obligations who need audit-grade payment receipts for AI agent operations. No production deployment yet; design partners shape the specification and get first integration access.
No web form ; direct email keeps the conversation auditable on both sides. We aim for a human reply within two working days. For founders : if you prefer Signal or a video call, mention it in the message.