Grid Security - Grid Computing: Infrastructure, Service, and Applications - page 317

FIGURE 12.1

VOTES portal showing cancer clinical data query.

The access to the portal is through Shibboleth following the interactions
described previously. Figure 12.1 (left) shows the interface to one study
where information on cancer patients is being returned (the names are for
demonstration purposes only and not real identities). The results of this
query are returned on the right of Figure 12.1. Key to this is the various
attributes that are returned (right-hand side of browser interfaces). These
are delivered via Shibboleth interactions and used to personalize the
access to different services through the portal; that is, the portlets that are
accessible are based upon having the roles to see them. This model corre-
sponds to security models along the lines of “what you can see is what
you can do.”
However, remote data providers are unlikely to simply allow access to
their datasets for someone who has authenticated and provided the right
roles to a remote portal. They will want to make their own authorization
decisions. To support this, the remote services providing access to data are
also protected with PERMIS and have their own local security policies on
access and usage. When a user issues a query is federated to a remote ser-
vice provider, their authorization infrastructure (PERMIS) is coni gured to
pull the X.509 attribute certii cate associated with that user request to
make their own local authorization decision. In supporting this, the attri-
butes delivered via Shibboleth are kept in a VO-specii c attribute authority
(LDAP server) associated with the portal. Thus all service providers know
where to go to obtain the attributes that they need and have agreed upon
when requests for secure access to their datasets are made. When pulled,
these attributes are checked for authenticity and validity, and if accept-
able, the query is run and resultant datasets are returned. We note that the
infrastructure does not allow arbitrary querying. Rather, the queries are