The IAEA is an international body, IF your interpretation was correct and my proposal were followed we'd see messages by Iran that verify such and such public k

The IAEA is an international body, IF your interpretation was correct and my proposal were followed we'd see messages by Iran that verify such and such public keys for such and such figures and functionaries in Iran (through IAEA), with Trump claiming without proof that they made concessions, since in your scenario it should be in Trumps proclaimed interest to publish such a signed message, so it would help in the case that Trump were lying. Protocol instructs to ignore any communications by counterparty that was not signed. Unsigned communications don't count as happened.