Towards secure, optimistic, distributed, open systems

This thesis is about DODA, a Distributed Office Document Architecture, designed to facilitate secure, yet cooperative, document development. It is an object-oriented system, based on the abstraction of document objects and functionaries. A document object is a structured entity composed of sub-components called folios, which may be textual or hold document methods. A document's folios may be processed in parallel, through transactions that may produce document versions. DODA combines, in a novel yet coherent manner, well-known techniques from the fields of data protection, access and concurrency control. DODA offers a unified approach to providing mandatory access control, concurrency control, version control, semantic consistency, protection against tampering and an unforgeable audit trail, in a way which facilitates the replication and local processing of document folios by a number of users in parallel.