On Petri Net Representations of Cryptographic Workflows in Electronic Government

Cryptographic workflows are a concept with a high potential for electronic government. It has been developed in the literature on identity based cryptography. It allows a government as the issuer of an electronic document to enforce the recipient to carry out certain actions before the latter can read the document (policy enforcement). The present paper models the underlying processes by Petri nets and extracts the common features of these cryptographic workflow nets. It shows that they have a series of attractive properties. Further, the paper focuses on the fact that the complete workflow net is composed of a net PN₁, which models the production of the unencrypted document, and the cryptographic workflow net PN₂. It demonstrates that desirable properties of the Petri net PN₁ are inherited by the composed net. Hence, the incorporation of policy enforcements does not introduce constructs that would complicate the treatment of the arising Petri nets.