The receipt detects revision, not invention
The strongest honest statement about a signed certificate is that committed inputs have not changed since they were committed. A producer who fabricates at capture signs a receipt that verifies perfectly.
It is tempting to describe a signing-and-replay pipeline as removing the need to trust the issuer. It does not, and the gap matters enough to state on every surface that carries the claim.
What the chain establishes is revision detection: an input committed at issuance cannot be altered afterwards without the alteration being visible. What it cannot establish is invention: a producer who writes a wrong number at capture, then certifies it honestly, produces a certificate that passes every check.
Two further conditions are load-bearing and are easy to omit:
- Replay needs your own inputs. Verifying against the copy of the data the issuer supplied establishes internal consistency and nothing else.
- The public key must be pinned out of band. A certificate that carries the key used to check it is self-referential. The verifier treats a pinned key as mandatory for a positive verdict for exactly this reason.
On the witness
The design includes a co-signing witness seam. The shipped witness runs co-located with the signer, which means it is not independent — independence here is a property of who operates it, not of the code. Calling it an independent witness would describe a deployment that does not currently exist.
On refusal
Refusal is a signed, first-class outcome carrying its real reason rather than a generic sentence. A system that always returns a number is not more useful than one that says when it cannot stand behind one; it is just less honest about the same underlying uncertainty.