Research On Algorithm Of Database Watermarking Based On Error Control

Digital-watermarking technology is an effective technology for digital product copyright protection and data security management. We set a special significant marker(watermarking) in the digital product by some way for notifying copyright. Nowadays, requires of data sharing and data exchanging are increasing, safety control for database and copyright protection become especially important. However, because of low redundancy and frequent update of database, watermarking of database is hard to be embedded and easy to be attacked. In recent years, Watermarking of database becomes focus and hotspot in watermarking algorithm research field.The third chapter of the article puts forward a database watermarking algorithm based on Reed-Solomon (RS) code. Reed-Solomon error correct code can rectify more than one-bit error, it is a very ideal error-correct code, which improves recoverability of the watermarking. And it adopts watermarking sharing -algorithm based on Lagrange interpolation formula, which improves the security of watermarking. Even if the attackers get the watermarking embedded algorithm, they could only take out part of the sharing-watermark, and could not recover the original watermarking information. The watermarking algorithm based on Reed-Solomon code has the characteristic of low arithmetic complexity, little extra watermarking information, high security, which can be used for low capacity database.In order to reduce the probability of false-normal decoding of RS code, and improve more robustness of the watermarking, the fourth chapter of the article puts forward cross-RS error-correct code, and according to its feature, we propose embedded and extracted algorithm of cross-RS error-correct. By encoding the watermarking block with cross-RS algorithm, there are two groups of error-correct code for each bit of the watermarking information. When we are decoding, the two groups of error-correct code can monitor each other, so that, the probability of false-normal decoding is reduced. The watermarking algorithm based on cross-RS error-correct code has more arithmetic complexity, but better robustness, which can be used for the database that have more data, more embedded capacity, and higher requirement of robustness.By emulating experiment of the algorithm, we simulated three kind of typical attack, and analyzed the experiment results. Theory analysis and emulated experiment results showed that the proposed algorithm is robust, have good application.