Study On Digital Watermarking Protocol Of Information Security

The rapid development of web and multimedia technologies makes the multimedia products easy to be used and delivered. Meanwhile, due to digital products easily be duplicated and tampered, the pirate problem of digital products becomes more and more serious. As an effective technique of multimedia protection, digital watermarking technique has been researched widely because it doesn't affect the use of multimedia and prevents pirate.The paper focuses on the designs of watermarking protocols of information security. As most watermarking protocols are based on current cryptography and watermarking algorithm, we first describe the watermarking algorithm, such as time domains and discrete transform domains, and discuss the effectiveness of them. Secondly we mainly discuss the elliptic curve cryptography (ECC). As an important public-key cryptography, RSA depends on increasing the length of key to gain higher security. But this can bring inconvenience to distribution of vast multimedia. Elliptic curve cryptography, based on discrete logarithm problem, which has been proved to a difficult problem in math, has the merit of using shorter key size to provide high strength. The paper mainly introduces some contents of ECC, such as implement of secure elliptic curve, generation of key, key exchanged protocol and digital signature.The paper proposes a watermarking protocol derived from Sun's protocol based on ECC, which eases the burden of multimedia distribution in a certain extent. Meanwhile, the proposed scheme also solves the unconsidered two problems in Sun's protocol, one is that seller may embed the buyer's watermarking to anther higher value products to get higher compensation or frame the buyer;another is that the buyer must offer his private key in the course of arbitrage.