PaychainX seals every payment in a tamper-evident audit proof, then wraps it in a hybrid post-quantum envelope. The classical hash and signature are real and reproducible here today. Real ML-DSA arrives through the PQ sidecar on the roadmap. We clearly label what is live versus roadmap.
On June 22, 2026 the President signed an Executive Order, Securing the Nation Against Advanced Cryptographic Attacks, directing the move to NIST post-quantum standards. It calls out the harvest now, decrypt later threat, where adversaries capture encrypted data today to break it once a quantum computer exists. The deadlines are concrete:
PaychainX is built for this. The audit envelope already reserves the exact NIST slots, pq_sig: ml-dsa for signatures and pq_kem: ml-kem for key establishment, so the migration is wired into the architecture today, ahead of the federal timeline. A payments platform that can prove a quantum-resistant audit trail is years ahead of processors that have not started. Read the Executive Order.
Every payment commits to a tamper-evident proof: proof_hash = SHA‑256(canonical(payload)), where canonical JSON sorts keys recursively. This reproduces the gateway's real audit proof (hash_algorithm: sha256) in your browser.
Today's live proof is the SHA-256 audit above. The roadmap upgrade is drop-in and happens in two steps: widen the integrity digest to SHA‑512, then populate the reserved signature field with a post-quantum signature (pq_sig: ml-dsa, pq_kem: ml-kem) from a vetted sidecar. This panel demonstrates that upgraded envelope in your browser: it computes pq_hash = SHA‑512(canonical(pq, payload)) and an HMAC-SHA512 stand-in for the signature, with a hybrid_attestation block. The envelope shape never changes, which is what makes the migration drop-in.
Every payment emits a SHA-256 proof_hash over canonical JSON.
The proof record reserves the signature and signature_algorithm fields, ready for the PQ upgrade.
Swap the in-process fallback for a vetted ML-DSA provider via the PQ sidecar.
Set pq_mode to hybrid-enforced so every audit requires a valid PQ signature.
Rotate pq_key_id on schedule; old keys stay verify-only until events expire.
Backwards compatible at every step. The envelope shape never changes, so merchants integrate once and the PQ guarantees strengthen underneath them.