David, I believe that I understand your point; however, I fear we are missing the more important issue--business process. It is my view, and the view of many others, that the MSH is intended to support business processes. There are valid business processes where the security services applied to the payloads must persist beyond the MSH to the application. There are financial and mortgage models where the signatures must persist, and be added to, over time. The confidentiality requirements are just as real--especially with HIPAA on the horizon. I must agree with Arvola that we carefully explore the use of XML-Enc and XML-DSig. I do not believe that encrypting the MIME package provides the persistent security that is demanded by the business processes. Ralph Berwanger