Now GO CHECK for proof.  An email = transaction.  The year was 2008.  The year I married my lovely wife 💕   I was just a young 21 year old in college at Southern Oregon University.  The paper was just an assignment that I wrote and I couldn't find the reference for W. Dai.  So my prof. told me he couldn't except the draft until I found the reference.  He suggested I email Wei Dai.  And you know some of the rest of the story.