Thursday, October 8, 2009

GAARDS Security implementation.

So, my next task for the coming months is to learn, tinker-with, and hopefully implement some cool bits of the GAARDS service as made by the folks up at Ohio State and their work with CaBIG and CaGrid. After a few preliminary readings of white papers and discussions with other people who have investigated various security models, I'm going to try and summarize things as I understand them, and invite people to correct my summarizations...

Globus works with X.509 certificates. To save a lot of complicated two-stepping, I'd say the easiest way to think of a certificate is as a licence with a special key embedded in them. Two nodes wanting to talk to each other have to present their certificates order to access services and establish secure communication, and the nodes have to "trust" each others certificates.

The way to get "automatic" trust without having to add keys into individual trust stores would be to have all the certificates issued by a trusted third party like Verisign or Thawte. This is like getting a passport or a drivers license as ID instead of having a business card with your name on it. It is also expensive, and to have to do it for every node on the grid beyond 5-node grids is pretty much unscalable.

Enter Dorian. Dorian is a GAARDS component and is essentially a Grid Service that allows other authentication methods to be used to access the grid. On one hand, it allows for someone to say "people authenticated by [method] at [node] are allowed to access these grid services". Thus, instead of having to have a certificate, one might just need to enter a username and password, or use their operating system credentials, or use a certificate issued by the Node itself instead of a larger third party.

The other critical component is Grid Trust Services (GTS) which allows for grids with different certificate sets to talk to each other and delegate which services on each grid are available to others. It also performs important syncing functions so that updates to access and authentication chains are propagated through the different grids.

There are other bits too, like GridGrouper which allows for simpler group paradigms (members of the group 'Gridviewer' would be able to access various gridviewers on different nodes... ) and Web Service Single Sign On which would allow an easy port for web applications to gain access to grid services... and you can read about it at the GAARDS website

Either way, I am at the periphery of understanding right now. I hope within a couple of days to have a really good grip on how security works now (and it's limitations) use cases for what we need, and a stronger correlation to how GAARDS will answer those use cases and which components are needed to do it.

Then, over the next couple of months, I'll need to implement those pieces and see what service modifications are needed to use them.

1 comment:

Jeremy Espino MD said...

Peter, feel free to look at our RODS GIPSE code to see how to access Dorian, Grid Grouper and Proxy Delegation Service.

Thomsun took some time to work it all out so hopefully you can benefit!

- Jeremy