encrypt.el in No Gnus 0.7 (was: New Emacs facilities from Gnus)

[Ted Zlatanov]

On Mon, 29 Oct 2007 08:49:10 +0100 Reiner Steib <address@hidden> wrote: 

RS> I'll provide a list of new files [in No Gnus 0.7] with some
RS> comments.  If you need to know more about these files, I'd suggest
RS> to make a _separate_ reply and cc the author or maintainer.

...

RS> * encrypt.el:

RS> ;;; encrypt.el --- file encryption routines
RS> ;; Author: Teodor Zlatanov <address@hidden>

(I haven't brought this up sooner due to lack of time, but this seems
like a good chance to discuss it)

This could go into mainline Emacs if people are interested.  For Gnus it
lets a user encrypt the .netrc file for example (I modified netrc.el
accordingly).  It can encrypt/decrypt any file (ciphers are matched with
the file path) and doesn't interfere with the regular Emacs file
facilities since it provides a separate API.  Software has to explicitly
use the encrypt.el API, e.g.

(let (encryption-model (encrypt-find-model file))
     (if encryption-model
            (encrypt-insert-file-contents file encryption-model)
          (insert-file-contents file)))

It uses password.el to manage passphrase caching.

I posted instructions on usage to the ding list, but they haven't gone
into the manual (partly because I didn't know if people would complain
about encrypt.el, or if it would eventually move to mainline Emacs).

FWIW, I think it's really nice to encrypt the .netrc file when you are
on a shared machine.  Then you can put IMAP passwords, etc. in the file
without the obvious plaintext risks; one passphrase decrypts the whole
thing and you don't enter any more passwords until the passphrase
expires.

Ted