The security model
Recognitium’s security does not rest on our honesty, our servers, or our survival. It rests on the arithmetic of SHA-256 — which is the same for everyone, everywhere, at any power level.
What a receipt proves — and what it does not
A receipt proves that a specific hash was settled at a specific position in an append-only sequence, at a specific time. It is proof of when, bound to proof of integrity. It does not certify that the content behind the hash is true, lawful, or authentic — that boundary is stated plainly in the Proof Policy. A system that overclaims is a system you cannot audit; we prefer the smaller, provable claim.
SHA-256 only. No keys in the sealing path.
The core settlement path contains no asymmetric cryptography — no signing keys, no certificates, no key ceremony. There is no private key whose theft would let anyone forge a receipt, no rotation schedule to miss, and no authority whose compromise cascades. Verification is pure recomputation: anyone with the receipt’s public fields recomputes one SHA-256 digest and compares. The arithmetic either agrees or it does not.
SHA-256 preimage resistance is categorized by NIST at Category 5 — the highest security level it defines for post-quantum evaluation.
Collision-indifferent, not collision-immune
We do not claim SHA-256 collisions are impossible. We claim something more defensible: the design does not lean on their impossibility. A receipt commits to the specific preimage its holder possesses. To exploit the scheme an attacker needs a second preimage for a hash that is already fixed on the chain — which is exactly the preimage-resistance property, not the easier collision game. That distinction is deliberate, and we state it precisely.
Post-quantum posture
Shor’s algorithm breaks RSA and elliptic curves. The sealing path uses neither, so there is nothing for it to attack. A quantum adversary is left with unstructured search against a 256-bit preimage — the problem class NIST rates Category 5. We state this as a posture, not a slogan: no cryptography is “quantum-proof”, but hash-based settlement is the conservative position available today.
Verify without us
Every receipt is verifiable with the internet off. The client verifier runs from a local file on your machine; the online verifier checks the live chain; and the specimen receipt on our homepage verifies itself in your browser with WebCrypto. No account, no permission, no us. If Recognitium disappeared tomorrow, every receipt ever issued would still verify.
Your content never reaches us
Hashing happens on your side, before anything is sent. The rail receives fingerprints — 32 bytes of SHA-256 — never documents, messages, or data. We cannot leak, sell, or be compelled to disclose content we never held. Client chains stay in their owners’ custody; we do not take third-party custody of them.
What a receipt proves, and what it does not
Recognitium sells proof capacity. A tick is spent when an approved fingerprint is settled, and a receipt is issued. The document, file, image, prompt, record or private data behind the fingerprint never has to leave your environment.
Hash-only settlement. You hash locally and approve only the resulting SHA-256 for settlement. Recognitium receives the fingerprint, never the material behind it.
An issued receipt records a settled event. It binds the approved fingerprint, the sequence position, the timestamp, the previous chain state and the new chain state into a portable proof.
Verification is public. It needs no login, no account and no disclosure of the original. A third party can check the receipt, or a Proof Certificate, without ever receiving the private data.
Account status changes nothing already issued. Unused balance, suspension, expiry or closure of an account does not alter the verifiability of its receipts.
A receipt does not certify content. It proves that this exact fingerprint was settled at that position and time. It says nothing about what the data means, unless the holder discloses the original and shows that it hashes to the settled value.
Tick balance is spent. Issued receipts remain verifiable. Private data remains private.
Reporting a vulnerability
If you believe you have found a security issue, write to security@recognitium.com (fallback: jose@recognitium.com). Machine-readable coordinates live at /.well-known/security.txt (RFC 9116). Every report is read and answered by the founder.