Forensic Readiness for Cloud-Based Distributed Workflows

摘要

Distributed workflows in the physical world can be documented by so-called process slips, where each action in the process is assigned to the responsible person and progress or completion of sub-tasks are confirmed using signatures on the process slip. The paper version creates a paper-based audit trail that documents who has done which part of the process and when. In the digital world, electronic process slips have been proposed that use digital signatures to achieve a similar behaviour in distributed service-based processes. This also provides a trail of linked digital signatures to represent the process. When moving such distributed workflows to the cloud (at least partly), steps might be fully automatic or only initiated by the user without any clear control on the execution of the process. Therefore, documenting the user interaction is not sufficient. This paper proposes to extend the idea of electronic process slips by hardware-based security to control the cloud server and to securely document the execution of particular steps in the process. The concept is based on Trusted Platform Modules (TPM) as specified by the Trusted Computing Group (TCG).The result is an electronic audit trail that provides reliable and secure information on the execution of the electronic process that ensures the satisfaction of specific requirements for forensic readiness in distributed workflows including cloud-based services. The composition concept remains as powerful as in the original version of the electronic process slip.