The credibility problem

Every platform claims “immutable audit trails.” But an audit trail controlled by the operator is not independent proof. Any company can assert that its logs are tamper-proof — there is no external evidence to back that claim.

Blockchain anchoring changes the equation: instead of “trust us, we log everything,” it becomes “here is the cryptographic proof — verifiable on a public blockchain that neither we nor anyone else can manipulate.”

How it works

NeuraPay’s approach does not store data on a blockchain. Instead, it anchors cryptographic fingerprints of audit events on public chains:

  1. Event hashing — Every audit event (communication sent, payment recorded, AI decision made, legal filing submitted) is hashed using SHA-256. No personal data enters the hash input.

  2. Merkle tree aggregation — All event hashes from a given period are aggregated into a Merkle tree. This allows any single event to be verified later without revealing all other events.

  3. Dual-chain anchoring — The 32-byte Merkle root is written to two independent blockchains:

    • Ethereum via the Ethereum Attestation Service (EAS) — structured, schema-based attestations
    • Bitcoin via OpenTimestamps — the ultimate long-term timestamp on the most secure chain

What this proves

When an auditor or regulator wants to verify a specific event:

  • NeuraPay provides the event, its Merkle proof, and the period reference
  • The auditor independently recomputes the hash, verifies the Merkle proof, and checks the root against the public blockchain
  • The block timestamp proves the event existed in exactly that form at that point in time

This verification requires no NeuraPay access — only a standard blockchain explorer.

Why dual-chain

Ethereum provides structured attestations with schema metadata (event count, period, version). Bitcoin provides the longest-running, most secure timestamp chain in existence. Together, they form redundant, independent proof chains. If one chain experiences issues, the other still holds.

Cost and scalability

The Merkle tree approach means costs do not scale with event volume. Whether NeuraPay processes 10,000 or 10 million events per day, the blockchain cost remains the same: one transaction per anchoring period. Estimated monthly cost: CHF 95–365.

  • Swiss DLT Act (2021) — Legal framework for blockchain applications in Switzerland
  • ZertES — Qualified electronic timestamps with evidentiary value
  • eIDAS — EU interoperability for electronic trust services
  • French Court Marseille (03/2025) — Blockchain timestamps accepted as judicial evidence

No personal data on-chain

Only cryptographic hashes are written to the blockchain. Case IDs are internal references, actors are pseudonymized, and action payloads are hashed before inclusion. The approach is fully GDPR and Swiss DSG compliant.

What this means for NeuraPay clients

Every action in the platform — from the first reminder to the final legal filing — carries a cryptographic proof of existence that is independently verifiable, permanently stored, and legally meaningful. This is not a feature. It is a foundation for trust.