Controlled demo · fictional data · ephemeral test key
Change one character. Watch integrity fail.
This demonstration creates a controlled UDS state, computes its canonical SHA-256, signs that hash with an ephemeral Ed25519 test key, and keeps signer identity explicitly unverified. No production key or real identity is used.
What this proves
The original exact state passes integrity. A changed copy fails. The controlled signature can remain mathematically valid for the original hash while the identity behind the ephemeral key remains unverified.
It does not prove the document’s statements are true, establish trusted time, or claim a trusted signer.