Algorithms for tractable compliance problems

in Frontiers of Computer Science (2015), 9(1), 55-74

In general the problem of verifying whether a structured business process is compliant with a given set of regulations is NP-hard. The present paper focuses on identifying a tractable subset of this ... [more ▼]

In general the problem of verifying whether a structured business process is compliant with a given set of regulations is NP-hard. The present paper focuses on identifying a tractable subset of this problem, namely verifying whether a structured business process is compliant with a single global obligation. Global obligations are those whose validity spans for the entire execution of a business process. We identify two types of obligations: achievement and maintenance. In the present paper we firstly define an abstract framework capable to model the problem and secondly we define procedures and algorithms to deal with the compliance problem of checking the compliance of a structured business process with respect to a single global obligation. We show that the algorithms proposed in the paper run in polynomial time. [less ▲]

Design and formal verification of a certified email protocol with transparent TTP

in Frontiers of Computer Science (2013), 7(2), 279-297

In certified email (CEM) protocols, trusted third party (TTP) transparency is an important security requirement which helps to avoid bad publicity as well as protecting individual users’ privacy ... [more ▼]

In certified email (CEM) protocols, trusted third party (TTP) transparency is an important security requirement which helps to avoid bad publicity as well as protecting individual users’ privacy. Cederquist et al. proposed an optimistic certified email protocol, which employs key chains to reduce the storage requirement of the TTP. We extend their protocol to satisfy the property of TTP transparency, using existing verifiably encrypted signature schemes. An implementation with the scheme based on bilinear pairing makes our extension one of the most efficient CEM protocols satisfying strong fairness, timeliness, and TTP transparency. We formally verify the security requirements of the extended protocol. The properties of fairness, timeliness and effectiveness are checked in the model checker Mocha, and TTP transparency is formalised and analysed using the toolsets mCRL and CADP [less ▲]