Entropy observation
A captured record of unpredictable public entropy from the NIST Randomness Beacon, the Stellar ledger, or the Bitcoin blockchain, hashed, Ed25519-signed, folded directly as a Merkle leaf into a Truestamp block, and named as a witness by the items submitted after it.
Overview
An entropy observation is Truestamp’s record of one captured value from an external entropy source: a NIST Randomness Beacon pulse, a Stellar ledger close, or a Bitcoin block. The observation stores the raw source data exactly as published, a deterministic SHA-256 hash of its canonicalized form, and a per-observation Ed25519 signature over a composite hash that binds the observation’s id, data hash, metadata hash, and signing key id. Because the captured value could not have been known before the public source published it, an observation is evidence that a moment had already passed, which strengthens the submission window guarantee. Observations are public data readable by anyone.
An observation carries that evidence into a proof by two independent routes.
- As a Merkle leaf. The composite hash becomes a Merkle leaf directly in a Truestamp block’s tree, alongside the item hashes in the same block, with no wrapper record in between. That makes the block itself provably not precomputed.
- As a witness. When an item is submitted, the data hash of the newest captured observation from each source is recorded in the item’s system-generated metadata and hashed into its composite fingerprint. A source with nothing captured yet contributes no entry. Here the observation binds to the individual item rather than to the block, and a proof bundle can carry that observation’s captured payload in full, so the submitted-after edge can be confirmed against the public source directly.
See entropy sources for how observations are captured and verification levels for how anyone can independently check one.