I told others d and e are "technically equivalent" and I just want to make sure that I am correct. You answer is more than I expected, thank you!

@kelalaka Yes this is exactly what I want to know, thanks!

It is not secure as long as you started to notice and to think about it. However, if I can generate a paragraph that is so natural, how would you even notice me among the millions of postings, say, on this website? This is my point.

@EllaRose If so, for each time I want to pass a secret, I would need to find a way to inform Bob what book and the location of each words in the book, which compromise the pre-requisite, i.e., I don't want any direct contact with Bob (of course we need to share a common secret at the beginning).

@mikeazo good suggestion. I ask it here because I started thinking this question when I was trying to understand steganography: instead of "squeezing" secret into the carrier, why not try to generate the carrier out of the secret? Another reason I ask it here is because I want to know if this is too crazy an idea that is not even being thought about by cryptographers.

Given the secret "let us attack tonight at ten", I want the AI to come up with a paragraph, which reads natural to human, whose first word start with 'l', 51-th word start with 'e', 101-th word start with 't', 151-th word start with 'u', and so forth.