Silence you can verify.
Every hour, a public randomness beacon opens an epoch. Crovia fetches the model cards of the AI systems under watch, runs a published predicate over the bytes — does this card name its training data? — commits every answer to a sparse Merkle map, signs the sheet and anchors it in Bitcoin. When a lab stays silent, the silence stops being an opinion and becomes a proof anyone can verify offline.
Silence is the evidence nobody keeps.
The model card that named nothing
A lab ships a frontier model. The card never names a single training source. A year later, in discovery, counsel argues they "always disclosed responsibly." Who holds the hourly, Bitcoin-anchored record that says otherwise?
The disclosure that quietly appeared
A training-data paragraph shows up on a card the week a lawsuit is filed. Their git history is theirs to rewrite. Crovia's map isn't — the hour the card first said it, and every hour before when it didn't, are committed under a root that Bitcoin already timestamped.
Article 53 wanted a summary
The EU AI Act requires a public summary of training content. For the models we observed between January and June 2026, that summary was mostly absent — and Crovia can name the exact hours it stayed absent.
FMTI rates what companies choose to disclose. Ranking sites rank what's popular. Both measure presence.
Crovia certifies, with a public randomness beacon on one side and a Bitcoin block on the other, what a company did not disclose — and for exactly which hours. We call the protocol TACET: verifiable silence.
Presence is easy: it's already published. Absence is the hard part — you have to prove a negative, contemporaneously, in a way that survives cross-examination. It's the only part that holds up in court.
The LACUNA certificate
A LACUNA certificate states one cryptographically defensible fact: during a defined window, Crovia fetched a model's public surfaces hour by hour, ran the published predicate, and found no training-data disclosure — each observation signed, each hour opened by drand and closed by a Bitcoin anchor. The opposing party can verify it without trusting Crovia.
How a silence becomes evidence
The epoch starts with a drand beacon round nobody can predict. Anything committed under it provably happened after that hour began.
Crovia fetches each model card over TLS, keeps the bytes, and runs the public predicate. Result, hash of the page, certificate and IP are signed as a snapshot.
Every snapshot updates one slot in a sparse Merkle map. The new root, the previous sheet and the beacon go into a signed epoch sheet. Slots move forward only.
The sheet hash is timestamped on Bitcoin via OpenTimestamps. Now the hour is sandwiched: after the beacon, before the block. A silence proof is the chain of those sandwiches.
Don't trust us. Verify us.
- Read the log. Every epoch sheet, snapshot and map change is public JSON under
/registry/data/tacet/. Start with latest.json. - Verify a silence proof offline.
pip installthe reference implementation, download a.seal.jsonfrom proofs/, runtacet-operator verify. It recomputes every root, checks the drand round, the Bitcoin anchors and the signatures — with no Crovia server in the loop. Step by step → - Re-run the predicate. The predicate is versioned and hashed into every snapshot. Fetch the same card and run it yourself; if you disagree with the verdict, the disagreement is about public code, not about Crovia.
- Check the 2026 archive. The AXIOM ledger is public at
/registry/data/substrate/, with its Bitcoin anchor manifest and an in-browser signature check. Silence figures cover January–June 2026. Envelopes issued after that day stay in the same file as continued collection.
Proofs are wrapped in a Crovia Seal — an open standard, IETF Internet-Draft draft-crovia-seal. Apache-2.0 + CC0.
One cryptographic spine
The 2026 archive
Before TACET, Crovia ran a first generation of collectors that produced an append-only, Ed25519-signed ledger of disclosure observations. Silence figures on that ledger paused on 2026-06-01 and do not accrue. Collection continued after that date and stays in the same file, dated, apart from TACET epochs. The ledger and its Bitcoin anchors remain public and verifiable.
The ledger total above is the whole file. Silence figures use the January–June 2026 window. Envelopes issued after 2026-06-01 are continued collection, not a silence proof and not a TACET epoch.
Source: _home_pulse.json · silence_index.json · substrate/ots_anchors.json · explore at /registry/explore/
When "we observed silence" isn't enough
For active litigation and regulatory work, Crovia produces court-ready forensic dossiers: the TACET proof for your model and window, the archived surface copies, the predicate source, memorization probes on closed models, and a per-model EU AI Act Art. 53 timeline — every claim backed by a signed, anchored object.
Confidential · engagement letter before any work · info@croviatrust.com