[Enigmail] My Bad, Sorry About That

[Alexander Dahl]

Hi,

>> In PGP this Key Selection is handled transparently via the 'Group'
>> function and with Enigmail is easily accomplished with the Per-Recipient
>> Rules.  Upon Joining such a Group or List there is a certain amount of
>> Set-Up required on the part of the New Subscriber.  This is what I
>> referenced " _a List_ " in My Original Post.
> 
> I guess I do not understand this. (You are, of course, correct that the list
> server need get my public key only once and keep it on hand locally, not do
> this with every mailing.)

The list server doesn't need your public key, at least the mail server
does not. The other list members do. So one could put the keyring on a
webserver.

> To send me an encrypted message, it must be encrypted using my public key,
> right? To send you an encrypted message, it must be encrypted using your
> public key too. 

Right.

> So if there are 5000 members of a list, the message must be
> decrypted by the list server using its private key (this is a very small
> overhead) and then encrypted 5000 times, once for each recipient, right?

I think not. You have to encrypt the message to all of the members. I
suppose that's what John meant with »Upon Joining such a Group or List
there is a certain amount of Set-Up required on the part of the New
Subscriber.« I think the others also have to adjust their settings by
adding the new subscriber.

What you propose is a special key for the server itself and some magic
on server side. You encrypt the message with the servers public key, the
server decrypts it and then reencrypts it with all the public keys of
the members. I never heard about that, I would not say this is
impossible, but I think it's not what John meant.

> Now it may be that gpg can do some of that one time only (the compression
> for sure and possibly the symmetric cypher), but then the public key part
> must be done once per recipient, which could be a nuisance.

I didn't understand that.

> Furthermore, would it not be more secure to send each copy with a different
> key for the symmetric key? I do not know which would be done on a mailing list.

So the server should not send one message encrypted to all members but a
message to each only encrypted with his own key?

Greets
Alex

-- 
'With the first link, the chain is forged. The first speech censured,
the first thought forbidden, the first freedom denied, chains us all
irrevocably.' (Jean-Luc Picard, quoting Judge Aaron Satie)
*** GnuPG-FP: 02C8 A590 7FE5 CA5F 3601  D1D5 8FBA 7744 CC87 10D0 ***

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