Encrypting and decrypting key and cert files about circe

[wasamasa]

I've looked into gnutls.c, apparently Emacs uses gnutls_certificate_set_x509_key_file instead of gnutls_certificate_set_x509_key_file2 (which is what the GnuTLS manual recommends). The latter supports a password argument for decrypting the key. This confirms my initial suspicion that this is best solved inside Emacs. If you happen to write/merge such a patch for Emacs or even convince the Emacs developers that this feature is important enough to bother with, feel free to let me know about it by submitting a link.

[wasamasa]

See irc.el for this. The key list is passed on as is to gnutls-boot-parameters. While it would be possible to write a function that generates a list of unencrypted file names, I doubt it makes much sense to leave unencrypted files on the disk to accomodate that interface. Instead the time would be better spent enhancing Emacs' gnutls integration to support encrypted files.

[wasamasa]

Relevant emacs-devel discussion: https://lists.gnu.org/archive/html/bug-gnu-emacs/2021-09/msg00858.html