In a way, he has already done it. When talking about the Xerox machine, he said this :
.... throwing up the nonsense Xerox machine, is what got us where we are today (referring to the criminal investigation.)
You can hear it here ( starts about 3:35 in ) :
Yup cypher. And likely much much more.
That is the “tell”
Once you go back, study what the Obots were saying, then realize what Zullo had in his hands a year ago, you have the answer. Zullo did not know what he had in his possession a year ago. Obots gave a key to identifying all whitehouse forgeries. Not just the longform of Soebarkah. I think we we are about to witness the unveiling of multiple forgeries.