[messaging] TOFU to ease PGP key discovery

[Daniel Roesler]

Interesting. Thanks for the reply!

FYI, keys.gnupg.net just CNAMEs pool.sks.keyservers.net, so you don't
need both in your list.

$ dig keys.gnupg.net ns +short
pool.sks-keyservers.net.

I'd also recommend https://keys.fedoraproject.org/, since they enable
TLS with a cert chained to a root CA.

-Daniel

On Tue, Feb 10, 2015 at 2:26 AM, Tankred Hase <tankred at whiteout.io> wrote:
> Hi Daniel,
>
>> 1. Are you using the sks-keyserver server or did you roll your own HKP
>> implementation. If you're using sks, can you elaborate on how you
>> setup your internal infrastructure and API to the core sks-keyserver?
>> If you rolled your own HKP, is there source code available? I'd love
>> to find an alternative implementation for HKP that's not written in
>> OCaml.
>
> Our key server is written in node.js, uses MongoDB and runs on AWS
> Elastic Beanstalk Infrastructure
> (https://aws.amazon.com/elasticbeanstalk/).
>
> Our server code is pretty specific to our service, so I don't know if
> it would make sense to open source that. Right now we are open
> sourcing only the client app.
>
>> 2. You mentioned on HN that you gossip with other keyservers[1]. Since
>> the gossip protocol is completely undocumented, do you know much about
>> how it works? I've been trying to read the OCaml, but have been
>> getting very lost. Hockeypuck[2] claims they can do this, but I don't
>> think it's the same gossip protocol, right?
>
> Our "gossiping protocol" is quite simple at the moment. We didn't
> implement a standard. It just act as a proxy to five common SKS
> servers. This is mainly because of the lack of CORS and reliability as
> mentioned in the blog post.
>
> If we don't find a verified public key in our directory, we proxy the
> following GET request:
>
> /pks/lookup?op=get&options=mr&search=<emailAddress>
>
> To these five servers and return the fastest response:
>
> 'https://pgp.mit.edu',
> 'http://pool.sks-keyservers.net',
> 'http://keys.gnupg.net',
> 'http://keyserver.ubuntu.com',
> 'http://pks.gpg.cz'
>
> These were the most reliable servers in my tests. Especially the
> ubuntu key server seems to be the fastest most of the time.
>
>> 3. When gossiping, do you accept new keys from other sources that have
>> a @whiteout.io domain? If I create a public key for "John Smith
>> <john.smith at whiteout.io>" and upload it to pgp.mit.edu, will that be
>> synced with your database?
>
> We don't sync. We proxy requests for fetches and uploads.
>
>> Third, FYI, there is CORS support for sks keyservers as of 1.1.5.
>> Also, many keyservers are mirrored on port 443 and using root CA
>> signed certs. I created an ajax publickey.js demo[3] using the
>> https://keys.fedoraproject.org/ keyserver. You're right, though, that
>> you can't just use hkps.pool.sks-keyservers.net, since the TLS
>> certificate in that pool must be signed by the SKS CA (which isn't a
>> root CA in pretty much every browser).
>
> Good to know thanks!
>
> Tankred
>
>
>> Thanks again!
>> Daniel
>>
>> [1]: https://news.ycombinator.com/item?id=9013852
>> [2]: https://hockeypuck.github.io/
>> [3]: https://diafygi.github.io/publickeyjs/
>>
>> On Mon, Feb 9, 2015 at 12:58 AM, Tankred Hase <tankred at whiteout.io> wrote:
>>> Hi,
>>>
>>> we've added HKP key server support to Whiteout Wail and have written a
>>> post about usability. Though I'd share it here:
>>>
>>> https://blog.whiteout.io/2015/02/06/making-pgp-key-management-invisible-so-johnny-can-encrypt/
>>>
>>> Thanks for any feedback!
>>>
>>> Tankred
>>>
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>
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