Every envelope in the AXIOM ledger is Ed25519-signed by the observer key published in trust_root.json. The ledger is Merkle-sealed hourly; the root is published in latest_seal.json; each new root is stamped with OpenTimestamps and listed in ots_anchors.json once confirmed in Bitcoin.

The claim is therefore: an envelope covered by an anchored root existed no later than the Bitcoin block that confirms the root, and has not been changed since.

• That an observation is true about the provider. It records fetched bytes, a hash over the assessed fields and a verdict; it does not infer intent.
• That a failed fetch is an absence. Collection failure is recorded as indeterminate and excluded from every absence count.
• Anything about time between observations. Streaks are bounded by the observation window (first_seen/last_seen).
• Resistance to a compromised observer key. The key is a trust anchor; if it leaks, historical anchored roots remain valid but new envelopes could be forged. Rotation is by publishing a new trust_root.json with the retiring key's fingerprint and its last sealed root.

Email info@croviatrust.com with a description and reproduction steps. Do not open a public issue for an exploitable problem. Acknowledgment within 72 hours; fix or public statement within 30 days.

Highest severity: a way to produce an envelope that verifies against the published key without the key, or a ledger modification that leaves a sealed root unchanged.