bug#8474: 23.2; smime feature requests

[Arik Mitschang]

I have two feature requests for the smime package included in gnus
shipped with emacs. The first is trivial and simply adds the AES
encryption standard to that which is supported by emacs smime (openssl
supports these, if there are many versions which don't perhaps adding a
note the the doc string to check before changing would be appropriate in
addition to the change). This change is implemented in the first
attached patch.

The second is somewhat less trivial, some folks will have there RSA
private key not encrypted for whatever reason and it can be fairly
annoying to have to enter a password for such keys each time (and in
cases where it would not be appropriate to change the password cache
time, one would have to). Since I found no real easy way to determine if
a key is encrypted other than to open the file and check every time, I
added another bit to the smime-keys variable allowing the user to
specify if that key is clear or not, and added optional args to the
signing and decryption functions along with a helper function that will
determine if the key (by email) needs a password or not. This is
implemented in the second attached patch.

Thanks,
-Arik

smime-new-sym.diff
Description: Patch adding AES cypher specs

smime-with-clearky.diff
Description: Patch allowing specification of clear RSA private keys