TradeReady seals each e-signature record with a digital key. Checking a record tells you whether it is still exactly as it was when it was signed.
This checks that the record is intact. It doesn't confirm who signed it: the record shows who had the signing link, when, and from where.
Choose the signature record (JSON) you downloaded from your signing link. Your browser checks it on this device; the file isn't uploaded.
Seals are Ed25519 signatures over the 32-byte SHA-256 of the record's canonical JSON (keys sorted, no spaces). Anyone can check them with these public keys.