What a receipt proves

Every SIMON job returns an Ed25519-signed receipt. It is checked in your browser by the same Rust verifier the command line uses. Here is exactly what a valid receipt does and does not tell you.

It proves

• The holder of one Ed25519 key signed this exact text for this job (the output digest is in the signature).
• Change one character of the text, or one signed field, and verification fails.
• If that key is on the plant's list of nodes (plant-listed node), the text came from that machine's key.

It does not prove

• Who the signer is, unless you pin the key. A receipt carries its own public key, so anyone can mint a key and sign any text. A valid signature from a key that is not listed shows as unknown node.
• Which model, quantization or precision ran. The node declares them; it can lie (see the verifier pilot for detection research).
• That the answer is correct or safe. Industrial tickets are also checked against the rules and reviewed by a technician.

How to use it

• Pin the keys of your own nodes (node_id in the gateway's nodes.json, or simon verify --signer).
• Treat unknown node as unverified, even when the signature is valid.

See it on real tickets: /industry · tamper with a receipt yourself: /demo