A technique for efficient representation of dependencies between electronically-stored documents, such as in an enterprise data processing system. A document distribution path is developed as a directional graph that is a representation of the historic dependencies between documents, which is constructed in real time as documents are created. The system preferably maintains a lossy hierarchical representation of the documents indexed in such a way that allows for fast queries for similar but not necessarily equivalent documents. A distribution path, coupled with a document similarity service, can be used to provide a number of applications, such as a security solution that is capable of finding and restricting access to documents that contain information that is similar to other existing files that are known to contain sensitive information.