to HKP and Hockeypuck on his blog here.]
Anyone who has ever used Ubuntu, Debian, Launchpad, or apt-get has implicitly trusted a sophisticated public key distribution protocol called "HKP" or, HTTP Keyserver Protocol. Originally designed for encrypting and signing email, asymmetric key pairs are used to sign, encrypt, decrypt and check signatures of thousands of packages on almost any Linux system.
Many (most?) public key servers today, such as keyserver.ubuntu.com, use an open source package called SKS (synchronizing key server) to distribute public keys.
Within Gazzang's zTrustee product, we rely on HKP to exchange public keys between client's and server. In our first implementation, we simply used SKS as installed from the Ubuntu repositories. SKS worked well in some environments, but it didn't scale well to larger environments, where hundreds of thousands of clients running on cloud servers were exchanging public keys in an automated fashion.
Moreover, we envisioned a system where user and host public SSH keys and server public SSL certificates might be exchanged in the same fashion, using the same protocol. We considered trying to extend SKS to improve the scalability and feature set.
In the end, we decided a new HKP implementation, leveraging a modern, high performance NoSQL key-value store -- MongoDB -- and written in modern language -- The Go Programming Language -- would enable us to build a more efficient, type-safe, memory-safe, concurrent, garbage-collected, fast implementation of HKP. We could also extend the feature set with a nice user interface and natively support other public keys.
With the general ideas fleshed out, my esteemed colleague, Casey Marshall, got to work on Hockeypuck -- his implementation of HKP in Golang and MongoDB -- freely available under the AGPL. All credit for the development of Hockeypuck up to this point goes entirely to Casey :-) That said, he's really quite interested in outside contributions and help at this point, so if you're proficient in Golang and looking to contribute to an awesome security project, here's your bogey!
We at Gazzang are hosting a reference Hockeypuck server at:
$ sudo apt-get install hockeypuck
in Ubuntu 13.04 to get your Hockeypuck server up and running. For other Ubuntu releases, Casey is publishing backports to a stable and an unstable PPA.
We're really, really interested in your feedback at this point! You can file bugs against the project and packages here. We're also looking for your feature requests... How would you like to use a public key server? Would you find it useful to import your SSH server or host public keys from a key server? Would you find it useful to see "badges" by keys, indicating that key's level or trust? Or perhaps that a key has been "verified"? What about linking public keys to OpenID or OAuth logins? Or what about [insert your idea here!]...
Comments? Bring 'em on!