Digital representation provides improved efficiency and accuracy in copying, storing and distributing content over the Internet. This improvement in digital technology has helped data to be easily duplicated and delivered quickly to a large number of users with minimal expense. This technology has become the most popular way to distribute multimedia content. Digital Rights Management (DRM) is a technology used by publishers and copyright holders to limit the illegal creation, copying and redistribution of media. But sometimes it's not enough to protect your media data. Here is the actual use of digital watermarking technology. Watermarking is a technology in which digital data is hidden within the host signal. Therefore it will help to verify the authority or integrity of the host signal. The traditional two-party digital rights management system only contains owner and consumer. But it's not enough to meet today's business and content delivery needs. Therefore, a multi-party and multi-level digital rights management architecture has been proposed [3]. The term multiparty refers to the multiple parties in the architecture such as owner, distributors, sub-distributors and consumers and multilevel refers to the multiple levels of distributors/sub-distributors, involved in the distribution chain. The DRM system manages media data in a compressed and encrypted format. The owner distributes this compressed and encrypted domain to the buyer through the multi-tier distribution network, where the distributors do not have access to the original content. However, to provide media authentication, track down traitors, or prove distribution, distributors must watermark this media content. This document works on the compressed watermark......half of the paper......[9]. There are two main disadvantages. They are 1) If encryption is performed on a message of a few bits in size, the size of the ciphertext may expand and will cause a loss of compression efficiency. 2) If encryption is performed on a large message of a few hundred bits in size bits, by compensating for the compression loss, the payload capacity decreases, where the payload capacity is the number of embedded watermark signal bits per encrypted message. So we select secure symmetric stream cipher with homomorphic property over secure asymmetric encryption with homomorphic property for the following two reasons. Symmetric ciphers with homomorphism can be applied on a smaller message size, such as a byte, without increasing the size of the compressed data and achieve better payload capacity than asymmetric counterparts. So we are using RC4 stream cipher with homomorphism property.
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