Chains and Layered Shards

Chains and Layered Shards

The part that makes UST more than "signed JSON": a single connected state does not have to be one document. It can be a chain of independently signed layers — each a full transcript with its own key, time frame and provenance, linked by content hashes (based_on + a recomputed seed). The existence, order and lineage of every layer are publicly provable, while each layer's content is disclosed only to whom it is meant for.

Graduated visibility

• Public observation — a normal captured layer anyone verifies at Assurance Tiers or above.
• Blinded (privacy: "blinded") — the value is replaced by a frame-bound commitment H(domain_shard, ust_id, nonce, name, value). Publish now, reveal later; the revealed {nonce, value} provably reproduces the original commitment, so it cannot be swapped, moved to another hour, or re-attributed. For embargoed results, private forecasts, positions, proof-of-priority.
• Encrypted (privacy: "encrypted") — ciphertext and commitment coexist; after decryption the verifier checks the plaintext reproduces the same commitment (E-COMMIT on mismatch). "The ciphertext really contains what was publicly committed" is a checked obligation, not a promise.
• Cross-party derivation (class: "derivation", based_on: [hash]) — a partner who receives a layer signs their own transcript on top, under their own key. An auditor later walks the whole chain, verifying each available layer independently.

Two rules that make it safe

• Trust composes, but is never inherited. Holding an outer layer does not vouch for the inner ones; each signature is checked on its own.
• Deletable without breaking the proof. Anchors commit to hashes, not contents — sensitive payloads can be destroyed later while "this existed, in this order, at this time" stays provable forever, and nothing can be forged back under the old hash. (This is also how the open protocol reconciles with paid/sealed data: a public, free hash bridges to private prior data without leaking it.)

Different consumers hold different depths of the same reality — the public sees L1, a client L1–L2, a partner L1–L3, an auditor the whole chain — and every one of them can verify exactly what they hold. That is the protocol's real subject: differentiated, provable access to a shared machine state.

This layer is being formalized as a first-class surface — Chains milestone.