The hoaxer encoded nonsense letters by scanning forward through a physical printing of the Declaration of Independence.
The smoking gun: both ciphers' max values land on exact page boundaries of a 4-page octavo (p ≈ 0.0001), they never once reference the 11 words that spill past the last page break, AND they got sloppier as each encoding session wore on, something no hoaxer would ever think to deliberately reproduce.