Attested Artifact Subject Binder

Computes the SPEC.md section 27.4 attested-artifact subject identifier for the sealed output of a pinned non-OCG producer: a spreadsheet, a reconciliation export, a report builder's PDF, anything with a content-addressed manifest but no kernel, no node and no chain. The identifier is sha256 over the JCS canonicalisation of exactly three members, tool_ref plus inputs_digest plus artifact, on the single canonical hash path; there is no fourth member and no wall clock, run identifier, host or session state enters it, so a verifier that never executed the producer recomputes the same value offline from the echoed preimage. tool_ref.manifest_digest is the chainless analogue of the section 17 kernel_digest and is what makes the producer tamper-evident rather than merely its output; its absence is reported, never assumed. Digest strings are hashed verbatim as declared and are never rewritten, so a malformed digest is named rather than silently normalised. Stated limit, normative: an attested-artifact subject carries no section 18 compute proof and no section 16 or 17 re-execution claim, it never evidences that the producer's arithmetic is correct, and the artifact omits replay_verified entirely rather than setting it false because no replay was attempted. This node identifies a subject so that separately signed section 27 approval records can name it; it signs nothing itself and asserts no regulator acceptance or filing sufficiency.

Tool URL: https://ainumbers.co/chaingraph/art-502-bind-attested-subject.html