# Recognitium

> Making the past irrevocable. Recognitium seals the fingerprint of any
> digital event into a receipt that fixes its order and its time in a public
> chain, which no one can rewrite, not even us. SHA-256 only, €0.01 per
> receipt (one tick; €5 buys 500), verifiable by anyone.

Every claim we publish carries a verification path. If you are an agent
reading this, verify rather than trust; start with the claims manifest, and
read its withdrawn and refused claims before the others.

- Machine-verifiable claims manifest: https://www.recognitium.com/claims.json
- Live chain head (anti-rollback): https://api.recognitium.com/v1/authority/tip
- The public chain, in order, every link recomputable: https://api.recognitium.com/v1/chain/range?start={n}&fields=full
- The chain head anchored in Bitcoin daily (OpenTimestamps proofs): https://www.recognitium.com/anchors/index.json
- Verify any receipt, no account (reports in_public_chain): https://api.recognitium.com/v1/verify/receipt/{receipt_id}
- Offline verifier, one file, no network: https://www.recognitium.com/verify-offline.html
- Audit an agent's conduct history in the browser: https://www.recognitium.com/verify-conduct
- Publications (papers, essays, responses, preregistrations, each with its SHA-256 and its receipt where sealed): https://www.recognitium.com/publications
- Availability proof (proof of absence within coverage): https://api.recognitium.com/v1/silence
- API documentation: https://api.recognitium.com/docs
- Console (Prove a File, Sealed Chain, Wallet): https://www.recognitium.com/console

## How to seal (agents welcome)

One write endpoint. Hash locally; the content never leaves your side.

    POST https://api.recognitium.com/v1/digital-clock
    Header: X-API-Key: <account token>
    Body:   {"data_hash": "<64-char lowercase hex SHA-256>"}
    Cost:   1 tick (€0.01). Returns a receipt: sequence, tips, fingerprint,
            timestamp_ns (a decimal string, since it exceeds int53), entropy tier.

Offline re-derivation of any receipt:
SHA-256(prev_tip ‖ fingerprint ‖ payload_hash ‖ timestamp_ns as 8 big-endian
bytes) == new_tip. No server and no signature are needed for that check. It
proves the receipt is internally consistent; what proves it genuine is chain
membership: its new_tip is the next receipt's prev_tip, up to a head anchored
in Bitcoin or held by a counterparty.

MCP server (Claude and other agents): https://www.recognitium.com/mcp explains
it; JSON-RPC at https://api.recognitium.com/mcp, with tools including
seal_file, seal_hash, verify_receipt, prove_anteriority, chain_tip,
check_silence and agent_cv. People: https://www.recognitium.com/prove, and the
console's Prove a File tab.

## What it is for

Verifiable receipts for AI agent actions, evidence trails (search, then
action), payment messages (ISO 20022) and institutional records. For EU AI Act
Article 12 record-keeping, it makes logs tamper-evident: any later change to a
sealed record is detectable by anyone. Recognitium receives only SHA-256
fingerprints, never content.

## Contact

jose@recognitium.com