Order of lookup methods in --auto-key-retrieve

[Andre Heinecke]

Hi,

On Sunday 30 June 2019 21:36:56 CEST Wiktor Kwapisiewicz via Gnupg-devel 
wrote:
> The code checks first the keyserver and then the WKD domain. I guess 
> this is to limit the number of IP-leaking queries and prefer trusted 
> keyserver.

I do not think that this is really the reason. As we have the fingerprint when 
we verify a signature it is more accurate to look for a key with that 
fingerprint on the keyserver instead of only matching the sender address with 
WKD.

> I'm wondering if reversing the order (first WKD, then keyserver) 
> wouldn't be a better option. The current mechanism is not perfect, so 
> that the IP-leaking could still be triggered by attacker by using a 
> brand new key (that is not published on keyservers).

I am fully with you. I've complained about this in the past, but It is not so 
important to me anymore because in GpgOL I no longer use "auto-key-retrieve" 
until I can show the unverified mail while the key is fetched.

For me it is even more important because GpgOL assigns keys that were fetched 
through WKD some additional trust (Level 2) by using the key origin, because 
the mail domain owner asserted this key. So if you have a key both on the 
keyservers and WKD you will get a different trust level if you receive the key 
by verifying a mail or if you receive the key by a "locate-key" when entering 
the sender address.


I thought we had an issue for that already but I did not find it. So i've 
cerated a new one. https://dev.gnupg.org/T4595


Best Regards,
Andre

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