Robust watermarking of databases in order-preserving encrypted domain

Security of databases has always been a hot topic in the field of information security. Privacy protection can be realized by encrypting data, while data copyright can be protected by using digital watermarking technology. By combining these two technologies, a database’s copyright and privacy problems in the cloud can be effectively solved. Based on order-preserving encryption scheme (OPES), circular histogram and digital watermarking technology, this paper proposes a new robust watermarking scheme for protection of databases in the encrypted domain. Firstly, the OPES is used to encrypt data to avoid exposing the data in the cloud. Then, the encrypted data are grouped and modified by the use of a circular histogram for embedding a digital watermark. The common data query operations in database are available for the encrypted watermarking database. In receivers, the digital watermark and the original data can be restored through a secret key and a key table. Experimental results have shown that the proposed algorithm is robust against common database attacks in the encrypted domain.