Cloud computing is gaining tremendous momentum in both academia and industry, with more and more people and enterprises migrating their data and applications into the cloud. Cloud computing provides a new computing model with elastic scaling, a resource pool of unprecedented size, and the on-demand resource provisioning mechanism, which bring numerous challenges in implementing workflow management systems (WfMSs) in the cloud. Establishing scalable and cross-enterprise WfMSs in the cloud requires the adaptation and extension of existing concepts for process management. This paper presents a framework for how cross-enterprise processes can be implemented, secured, controlled, and scaled. We also explain why existing engine-based centralized and distributed WfMSs cannot guarantee the no repudiation requirement. The proposed framework is a document-routing system that implements major required security features such as authentication, confidentiality, data integrity, and nonrepudiation in the cloud computing environment. Its security framework is built by applying element-wise encryption and a cascade-based method of embedding digital signatures. The implementation and experimental results demonstrate the feasibility of the proposed framework.