There is known an information processing device which detects an illegal stored document in an electronic document database. This information processing device automatically selects a highly confidential document from among electronic documents, and confirms whether or not it is stored in a place of low importance.
An example of technology for detecting an illegal stored document is described in Patent Document 1.
A confidential document search system described in Patent Document 1 divides a document into headers, footers and body texts.
Then, on the basis of whether or not a language characteristic to each of the divided parts is contained, the confidential document search system identifies whether the document is confidential information or not. Simultaneously, the confidential document search system identifies what kind of confidential information the document is.
The confidential document search system also determines importance of the document in accordance with the importance of the category of the confidential information.