Automatic proxy-based watermarking for WWW

With the appearance of digital libraries and information archive centers on the Internet, copyright issues are becoming very concerning. Unlike hardco pies, digital data can be modified and distributed very easily. Watermarkin g is the solution to this copyright problem. By embedding a secure, identif iable mark on the digital data, ownership and content integrity can be ensu red. Currently, the watermarking process is usually done manually and off-l ine. This makes updating of watermarking techniques and watermark logo cont ent difficult. Enforcement of watermarking policies within an organization for providing content on the Internet is also not easy. Furthermore, instal ling watermarking software on each workstation of an organization is not ve ry cost effective. In this paper, we propose a novel approach to address th e copyright issues of digital data on the Internet. The basic idea is to mo ve the watermarking process from the content developers to a reverse proxy server that is usually close to the organization's gateway. Data will be wa termarked only when it is retrieved through this proxy. The main advantages of this approach are that: (i) it is cost effective as being independent o f the amount of data on the web server and also independent of the number o f content developers in the organization, (ii) it makes updates and mainten ance tasks easy, being an one-for-all solution, and (iii) the reverse proxy effectively enforces the watermarking guideline. Both design consideration s and implementation details of watermarking in a fully functional, Squid-b ased reverse proxy server are presented and its performance is analyzed. Al l results show that automatic watermarking in a reverse proxy server is a p ractical, cost efficient and enforcement effective solution for handling co pyright issues in Internet digital Libraries. (C) 2001 Published by Elsevie r Science B.V.