An Audit Logic for Accountability
  We describe and implement a policy language. In our system, agents can distribute data along with usage policies in a decentralized architecture. Our language supports the specification of conditions and obligations, and also the possibility to refine policies. In our framework, the compliance with usage policies is not actively enforced. However, agents are accountable for their actions, and may be audited by an authority requiring justifications. 
J.G. Cederquist, R. Corin, M.A.C. Dekker, S. Etalle and J.I. den   Hartog