The wor cryptex is a neologism coined by the author Dan Brown for his 2003 novel The Da Vinci Code, denoting a portable vault used to hide secret messages. It is a combination of the words cryptology and codex; "an apt title for this device" since it uses "the science of cryptology to protect information written on the contained scroll or codex" (p. 199 of the novel). Brown implies that a scroll and a codex are the same thing; however a scroll is a book that is unrolled a page at a time; and a codex is a book that can be opened to any page at will, two very different things. It is claimed in the novel that the original design came from the secret diaries of Leonardo da Vinci. In reality, though there is little doubt he possessed the mechanical skill to design such a device, there is no record of him actually doing so.