Kind Regards
There are a number of options and they tend to be split depending on
your intent to encrypt (DRM) the work or not.
In addition, if you will use firm to "publish" and/or distribute your
work, they will want to have input.
Some personal thoughts...
I really dislike any type of encryption... in most cases it will not
stop anyone from breaking the encryption anyway and it imposes
significant limits and problems on every legitimate reader of your work.
A few years back I republished a textbook my father wrote sixty some
years ago in ebook format and, after reviewing all of the options there
at the time, elected to go pdf format even though I really don't like
it. Why? It handles large (350 pages) works, searches well and
supports both internal and external hyperlinks.
Beverly Howard