Abstract
Securing data is becoming a crucial need for most internet-based applications. Whereas the problem of data confidentiality
has been widely investigated, the problem of how to ensure that data, when moving among different parties, are modified
only according to the stated policies has been so far not deeply investigated. In this paper, we propose an approach supporting
parallel and distributed secure updates to XML documents. The approach, based on the use of a security region-object
parallel flow (S-RPF) graph protocol, is particularly suited for all environments requiring cooperative updates to XML documents.
It allows different users to simultaneously update different portions of the same document, according to the specified
access control policies. Additionally, it supports a decentralized management of update operations in that a subject can
exercise its privileges and verify the correctness of the operations performed so far on the document without interacting, in
most of the cases, with the document server.
