Who wrote the private key on whiteboard just by looking at the public certificate?

https://plus.google.com/118187272963262049674/posts/TSDhe5CvaFe

During his own Google interview, Jeff Dean was asked the implications if P=NP were true.
He said, "P = 0 or N = 1."
Then, before the interviewer had even finished laughing, Jeff examined Google’s public certificate and wrote the private key on the whiteboard.

Flag: Jeff Dean