file encryption in Gnus: a roadmap attempt

[Ted Zlatanov <tzz@lifelogs.com>]

After a lengthy discussion on emacs-devel, here's my plan for adding
encryption to Gnus:

1) move what I used to call "gnus-encrypt.el" to "gencrypt.el" which
   will be an ELisp package maintained by me and/or others.

2) write a gnus-file.el package, which will provide generic hooks for
   all interesting Gnus file I/O; for instance newsrc.el will use it.

3) write code in gencrypt.el which will install encryption hooks into
   the gnus-file hooks.

This has to be done because of Emacs export restrictions.

I am trying to avoid writing a user-transparent file I/O layer;
gencrypt.el should be an API and then the file I/O layer can be built
on top, possibly inside gencrypt.el as well.

The most common question was, "why not just use file handlers"?  An
API allows much more control than file handlers, and can be
guaranteed not to interfere with other file handlers.  My experience
with crypt++.el has led me to avoid file handlers as a baseline
feature for encryption specifically.

Please let me know if you have questions and/or comments.

Ted