An enhanced watermarking protocol for electronic copyright management

In Piva et al\u27s watermarking scheme for electronic copyright management system (ECMS), authors were considered trusted potentially, so a dishonest author could authorize more than one distributor to sell her one document, named &quot;One Document to Multi-distributor&quot; problem, which would damage the benefit of the distributors. To resolve the problem, in this paper, we propose an enhanced watermarking protocol based on Piva et al\u27s scheme by introducing document nature code (DNC) and register records table. In addition, our protocol offers the distributor an efficient means to verify his right to an authorized digital document.<br /