Research Of Information Hiding Technologies Based On Digital Signature

Digital multimedia has got a rapid development with the swift development of information technology and internet. The digitization of multimedia have provided enormous convenience for its deposits and greatly raised the efficiency and accuracy of information expression. But the following side effect is also getting more and more obvious because of lossless copy and distribution of digital media: the right infringement and distortion is getting easier and easier. So, the intellectual property protection of digital multimedia has already been taken seriously day and day.As a means of copyright protection, digital signature technology has been extensively studied. But the traditional signature technology only satisfies text information authentication, which is sensitive to every bit of the input message. However, the digital signature of multimedia is based on content, because multimedia can allow for lossy representations with graceful degradation such as moderate levels of filtering, geometric distortion and noise corruption.Then, according to the multimedia technology based on hash methods, this paper proposed following new schemes:1. Image signature technology based on hash schemes. The histogram image signature method could resist revolving and zooming, but was sensitive to other unchanged content operations such as filtering and compression. By means of a key image, the image signature technology based on single variable V system extracted low frequency coefficients of V transformated image as its feature to generate signature. The experimental results showed that the scheme had good performance of security and robustness. It was resilient to moderate filtering, noising, 20% of cropping and JPEG compression operation up to 95% .2. Video signature technology based on V-system over triangulated domains. Using another kind of new orthogonal function, the low frequency coefficient of key frames was extracted to generate the final video signature. This method grately reduced the hash bit, which was convenient for storage and applications.3. Information hiding technology based on audio signature. Unified digital signature technology and information hiding technology, the audio signature was embedded to itself as a watermark to achieve the purpose of copyright protection. This article used DCT transformation to generate signature and embedded the signature to audio with V transformation and then transmitted the audio. The receiver generated the signature with the same method and compared it with the watermark extracted. If they were same, the audio was authenticated. The experimental results showed that this algorithm could resist to the audio sampling, the Gauss noise, and cropping up to 50%. Therefore, embedding the signature to audio which could greatly increase the transmission security was an effective measure of assuring information security under the network environment.