When an electronic document is made available for review by other entities, it is often convenient to store the document in a repository or database managed by a third party. A system is provided in which the originator of the document is able to ensure the integrity and security of its document filed...http://www.google.ca/patents/US6839843?utm_source=gb-gplus-sharePatent US6839843 - System for electronic repository of data enforcing access control on data retrieval
