Re: [Sks-devel] Protocol Details for HKP\HKPS\Gossip

[Kristian Fiskerstrand]

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On 02/09/2014 07:00 PM, Benny Baumann wrote:
> Hi folks,
> 
Hi Benny,


> because I know this might get a bit complicated let's split this in
> 3 parts:
> 
> 1. HKP: AFAIK this is based on HTTP/1.0, but is there any
> documentation on what possible calls could arrive at the server (in
> the logs I noticed /pks/lookup, /pks/hashquery and /pks/add, but
> it's somehow a bit troublesome to re-engineer the whole API when
> one was going to write some own frontend or caching interface. How
> accurate is the description[1] linked at [2]?

The protocol description should be fairly accurate, although some
additional parameters might have been added since. In particular I'm
using /pks/lookup?op=stats to determine inclusion into the pool, which
isn't documented. I'm doing this by parsing the HTML, so any deviation
from SKS would make this difficult, although I'm open to adding e.g. a
json alternative e.g. at ?op=stats&options=json. I'd then check for an
expected format or do a fallback to the usual HTML parsing for these
servers.

> 
> 2. HKPS: Any difference from HKP aside from tunneling by SSL and
> the pinning of the CA of the certificate?

Indeed only TLS-layered HKP. As for the actual implementation in my
pools see [0]

> 
> 3. Gossip: Is there some documentation of the binary gossip
> protocol? Having a rough look at the TCP dump I made for testing
> this looks like the OpenPGP data is sent in the clear, but
> unfortunately I didn't manage to get any more out of the dump. But
> given only the algorithmic description [3],[4] it's not quite
> feasable to come up with a complying implementation.
> 

I can only recommend looking into SKSs implementation of this. In
addition you might want to look into Hockeypuck, see e.g. the thread
at [1] as I understand Casey et al is also working on an alternative
implementation.

References:
[0] https://sks-keyservers.net/overview-of-pools.php#pool_hkps
[1] http://lists.nongnu.org/archive/html/sks-devel/2012-11/msg00037.html

- -- 
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Kristian Fiskerstrand
Blog: http://blog.sumptuouscapital.com
Twitter: @krifisk
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