A data distributor or a Business Process Outsourcing (BPO) company distributes sensitive data to a set of trusted companies or a set of agents (third parties). Some data can be leaked and found in an unauthorized place. The distributor will be identified by the agent who receives the actual data. Although existing water marking techniques have been successfully utilized for copyright protection of multimedia data, the research of database water marking technique is still facing a lot of challenges due to the differences between the relational database and multimedia data. Sometimes water marks can be destroyed if the data recipient is malicious.