Abstract: A system in which a sending entity creates a structured document and communicates that document to a receiving entity includes a transform to ensure that document elements are not moved during communication. The structured document is typically XML, and the document comprises a root element and a set of one or more child elements. At least one child element is protected, for example, by a digital signature, prior to being positioned within the XML document. This “signed” element includes a sending entity security policy, preferably in the form of a position dependent or absolute path expression. The receiving entity includes a transform that determines whether the signed element is in a given position within the received XML document. Typically, the given position is the position at which the signed element was placed within the structured document by the sending entity.