Provenance of exposure: Identifying sources of leaked documents

We design a provenance system for documents on clouds. The system allows writing documents by several collaborating individuals. Provenance allows recovery of information about the sequence of significant events relevant to the documents. Existing provenance systems focus on editing events, such as creation or removal of document parts. In this work, we introduce provenance of exposure events, allowing identification of one, or more, individuals which are possible sources of the exposure to external source of a particular version of documents. Our design provides a practical solution for provenance of documents via not-fully-trusted cloud systems, with support for provenance of both exposure and editing events.