Image Authentication with Dual Watermarks and Block Wavelet Transform for IP Networks
碩士 === 國立清華大學 === 資訊工程學系 === 89 === Digital watermarks have been proposed recently as a means for copyright protection of multimedia data. In this paper we emphasize that security of an image. A timestamp can record the original message’s digest and authentication time to prove...
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| Format: | Others |
| Language: | en_US |
| Published: |
2001
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| Online Access: | http://ndltd.ncl.edu.tw/handle/61112237079322381932 |
| Summary: | 碩士 === 國立清華大學 === 資訊工程學系 === 89 === Digital watermarks have been proposed recently as a means for copyright protection of multimedia data. In this paper we emphasize that security of an image.
A timestamp can record the original message’s digest and authentication time to prove the ownership of the original message. This is already used widely in many applications. In this paper we combined timestamp and encryption algorithm such as ECC for watermark embedding to prevent some attack like multi-watermarks and IBM attack. Besides this we also used adaptive block wavelet transform to search the significant coefficients in the LL band in order to increase watermark robustness.
Experimental result shows the watermark extraction after attacks like JPEG compression, noise corruption, cropping and edge sharpening. We also show a watermark that extracted with illegal timestamp or key.
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