Hiding data in blocks of Oracle Database

Abstract

In this paper, we explore the possibility of storing a hidden message in the physical data structures of the Oracle Database Management System (DBMS). We consider data blocks, the fundamental Oracle Database storage units for table data and other objects. As a result of normal usage, free space in data blocks gets fragmented. We devised a technique to form the desired fragmentation pattern in a data block. Assuming fragments of free space correspond to “0” bits, and fragments of data corresponding to “1” bits, we may store a secret message inside a block. In order to form the container, we need the object privileges to SELECT, DELETE and INSERT data. The SELECT object privilege is required to retrieve the message at a later time. The paper covers the technique of message embedding in detail. In conclusion we discuss various use causes for the technique. It should be noted that the operations of deleting and then adding rows lead to eventual damage to the steganographic container. In this regard, we studied the OLAP and OLTP database models. We conclude that OLAP databases are better suited for embedding secret messages due to the small number of the operations mentioned before.

Keywords

• steganography, data hiding, databases, database management systems, oracle database.