SecPAL
SecPAL is a declarative, logic-based, security policy language that has been developed to support the complex access control requirements of large scale distributed computing environments.

Common access control requirements
Here is a partial-list of some of the challenges that SecPAL addresses:
 How does an organization establish a fine-grained trust relationship with another organization across organizational boundaries?
 How does a user delegate a subset of a user’s rights (constrained delegation) to another user residing either in the same organization or in a different organization?
 How can access control policy be authored and reviewed in a manner that is human readable - allowing auditors and non-technical people to understand such policies?
 How does an organization support compliance regulations requiring that a system be able to demonstrate exactly why it was that a user was granted access to a resource?
 How can policies be authored, composed and evaluated in a manner that is efficient, deterministic and tractable?